MAXM17903AMB+T

**EVALUATION KIT AVAILABLE** 

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## **MAXM17903** 

## **General Description** 

The _Himalaya_ series of voltage-regulator ICs and power modules enable cooler, smaller, and simpler powersupply solutions. The MAXM17903 is a high-efficiency, synchronous step-down DC-DC module with integrated circuit and inductor that operates over a wide input-voltage range. The module operates from 4.5V to 24V input and delivers up to 300mA output current over a programmable output voltage from 0.9V to 3.3V. The module is an easy-to-use, step-down power module that significantly reduces design complexity, manufacturing risks, and offers a true plug-and-play power-supply solution, reducing time-to-market. The device employs peak-currentmode control architecture through the MODE pin that can be used to operate the device in pulse-width modulation (PWM) or pulse-frequency modulation (PFM) control schemes. To reduce input inrush current, the device offers an internal soft-start. 

The MAXM17903 module is available in a low profile, compact 10-pin, 2.6mm × 3mm × 1.5mm, uSLIC™ package. The device can operate over a wide temperature range from -40°C to +125°C. The package passes Vibration Standard JESD22-B103B and passes Mechanical Shock Standard JESD22-B104. 

## **Applications** 

- Industrial Sensors and Process Control 

- 4-20mA Current-Loop Powered Sensors 

- LDO Replacement 

- Battery-Powered Equipment 

- HVAC and Building Control 

- General Purpose Point-of-Load 

- USB Type-C Powered Loads 

_**Ordering Information** appears at end of data sheet._ 

_uSLIC is a trademark of Maxim Integrated Products, Inc._ 

## **4.5V to 24V, 300mA Compact Step-Down Power Module** 

## **Benefits and Features** 

- Easy to use 

   - Wide 4.5V to 24V Input Range 

   - Adjustable 0.9V to 3.3V Output 

   - ±1.44% Feedback Accuracy 

   - Up to 300mA Output-Current Capability 

   - Internally Compensated 

   - Requires Only 5 External Components 

   - All Ceramic Capacitors 

- High Efficiency 

   - Selectable PWM- or PFM-Mode of Operation 

   - Shutdown Current as Low as 2.2μA (typ) 

- Flexible Design 

   - Prebias Startup 

   - Open-Drain Power Good Output ( RESET Pin) 

   - Programmable EN/UVLO Threshold 

- Robust Operation 

   - Hiccup Overcurrent Protection 

   - Overtemperature Protection 

   - High -40°C to +125°C Ambient Operating Temperature Range / -40°C to +150°C Junction Temperature Range 

## **Typical Application Circuit** 

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12V 3.3V, 300mA<br>VIN OUT<br>1µF 10µF<br>EN/UVLO GND<br>200kΩ<br>MAXM17903<br>RESET FB<br>VCC LX<br>75kΩ<br>1µF<br>MODE<br>**----- End of picture text -----**<br>


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_19-100225; Rev 0; 12/17_ 

## MAXM17903 

## 4.5V to 24V, 300mA Compact 

## Step-Down Power Module 

## **Absolute Maximum Ratings** 

VIN to GND ..............................................................-0.3V to 29V EN/UVLO to GND....................................................-0.3V to 29V LX, OUT and GND .....................................-0.3V to (VIN + 0.3V) VCC, FB, RESET to GND ..........................................-0.3V to 6V MODE to GND .......................................... -0.3V to (VCC + 0.3V) 

Output Short-Circuit Duration ....................................Continuous Junction Temperature (Note 1) ........................................+150°C Storage Temperature Range ............................ -55°C to +125°C Lead temperature (soldering,10s) ...................................+245°C Soldering Temperature (reflow) .......................................+245°C 

_Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability._ 

## **Package Information** 

|**Package Information**|**Package Information**|
|---|---|
|**PACKAGE TYPE: 10-PIN uSLIC**||
|Package Code|M102A3+2|
|Outline Number|**21-100094**|
|Land Pattern Number|**90-100027**|
|**THERMAL RESISTANCE, FOUR-LAYER BOARD (Note 2)**||
|Junction to Ambient (θJA)|41.56 ºC/W|



For the latest package outline information and land patterns (footprints), go to **www.maximintegrated.com/packages** . Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 

**Note 1:** Junction temperature greater than +125°C degrades operating lifetimes. **Note 2:** Package thermal resistance is measured on an evaluation board with natural convection. 

## **Electrical Characteristics** 

(VIN = VEN/UVLO = 12V, VGND = 0V, CVCC = 1μF, FB = 1V, LX = MODE = RESET = OUT = unconnected; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted.) (Note 3) 

|**PARAMETER**|**SYMBOL**|**CONDITIONS**|**MIN**<br>**TYP**<br>**MAX**|**UNITS**|
|---|---|---|---|---|
|**INPUT SUPPLY (VIN)**|||||
|Input-Voltage Range|VIN||4.5<br>24|V|
|Input-Shutdown Current|IIN-SH|VEN/UVLO= 0V, shutdown mode|2.2<br>4|μA|
|Input-Supply Current|IQ-PFM|MODE = unconnected,<br>FB = 1.03 × VFB-REG|95<br>160|μA|
||IQ-PWM|Normal switching mode, VIN= 12V,<br>MODE=0|3.2|mA|
|**ENABLE/UVLO (EN/UVLO)**|||||
|EN/UVLO Threshold|VENR|VEN/UVLOrising|1.19<br>1.215<br>1.28|V|
||VENF|VEN/UVLOfalling|1.06<br>1.09<br>1.16||
||VEN-TRUESD|VEN/UVLOfalling, true shutdown|0.75||
|EN/UVLO Input-Leakage<br>Current|IEN/UVLO|TA= +25°C|-100<br>+100|nA|



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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Electrical Characteristics (continued)** 

(VIN = VEN/UVLO = 12V, VGND = 0V, CVCC = 1μF, FB = 1V, LX = MODE = RESET = OUT = unconnected; TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted.) (Note 3) 

|**PARAMETER**|**SYMBOL**|**CONDITIONS**|**MIN**<br>**TYP**<br>**MAX**|**UNITS**|
|---|---|---|---|---|
|**LDO (VCC)**|||||
|VCCOutput-Voltage Range|VCC|6V < VIN< 21V, 0mA < IVCC< 10mA|4.75<br>5<br>5.25|V|
|VCCCurrent Limit|IVCC-MAX|VCC= 4.3V|13<br>30<br>50|mA|
|VCCDropout|VCC-DO|VIN= 4.5V, IVCC= 5mA|0.15<br>0.3|V|
|VCCUVLO|VCC-UVR|VCCrising|4.05<br>4.18<br>4.3|V|
||VCC-UVF|VCCfalling|3.7<br>3.8<br>3.95||
|**SOFT-START (SS)**|||||
|Soft-Start Time|tSS||3.8<br>4.1<br>4.4|ms|
|**FEEDBACK (FB)**|||||
|FB-Regulation Voltage|VFB-REG|MODE = GND|0.887<br>0.9<br>0.913|V|
|||MODE = unconnected|0.887<br>0.915<br>0.936||
|FB-Leakage Current|IFB||-100<br>-25|nA|
|**TIMING**|||||
|Switching Frequency|fSW||465<br>500<br>535|kHz|
|FB Undervoltage Trip Level to<br>Cause Hiccup|||62.5<br>64.5<br>66.5|%|
|Hiccup Timeout|||131|ms|
|Minimum On-Time|tON-MIN||90<br>130|ns|
|Maximum Duty Cycle|DMAX|FB = 0.98 × FBREG|89<br>91.4<br>94|%|
|**RESET**|||||
|FB Threshold forRESET<br>Rising||FB rising|93.5<br>95.5<br>97.5|%|
|FB Threshold forRESET<br>Falling||FB falling|90<br>92<br>94|%|
|RESETDelay After FB<br>Reaches 95% Regulation|||2|ms|
|RESETOutput-Level Low||IRESET= 5mA|0.2|V|
|RESETOutput-Leakage<br>Current||VRESET = 5.5V, TA= +25°C|0.1|μA|
|**MODE**|||||
|MODE Internal Pullup<br>Resistor|||500|kΩ|
|**THERMAL SHUTDOWN**|||||
|Thermal-Shutdown<br>Threshold||Temperature rising|166|°C|
|Thermal-Shutdown Hysteresis|||10|°C|



**Note 3:** Electrical specifications are production tested at TA = +25°C. Specifications over the entire operating temperature range are guaranteed by design and characterization. 

Maxim Integrated │ 3 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Operating Characteristics** 

(VIN = VEN/UVLO = 12V, VGND = 0V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted. The circuit values for different output-voltage applications are as in Table 1, unless otherwise noted.) 

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EFFICIENCY vs. LOAD CURRENT  EFFICIENCY vs. LOAD CURRENT  EFFICIENCY vs. LOAD CURRENT<br>(VOUT = 0.9V, PWM MODE) (VOUT = 1.5V, PWM MODE) (VOUT = 2.5V, PWM MODE)<br>100 toc01 100 toc02 100 toc03<br>90 90 90<br>80 80 80<br>70 70 70<br>60 60 VIN = 5V 60 VIN = 5V<br>50 50 50<br>40 VIN = 5V 40 VIN = 12V 40 VIN = 12V<br>30 VIN = 12V 30 30<br>20 20 VIN = 20V 20 VIN = 20V<br>10 10 10<br>0 0 0<br>0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300<br>LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA)<br>EFFICIENCY vs. LOAD CURRENT  EFFICIENCY vs. LOAD CURRENT EFFICIENCY vs. LOAD CURRENT<br>(VOUT = 3.3V, PWM MODE) (VOUT = 0.9V, PFM MODE) (VOUT = 1.5V, PFM MODE)<br>100 toc04 100 toc05 100 toc06<br>90 90 90<br>VIN = 5V<br>80 80 80<br>70 70 70<br>VIN = 5.5V<br>60 60 60<br>VIN = 12V<br>50 50 50<br>VIN = 20V<br>40 VIN = 20V 40 VIN = 12V 40 VIN = 12V<br>VIN = 5V<br>30 30 30<br>20 20 20<br>10 10 10<br>0 0 0<br>0 30 60 90 120 150 180 210 240 270 300 1 10 100 1 10 100<br>LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA)<br>EFFICIENCY vs. LOAD CURRENT EFFICIENCY vs. LOAD CURRENT OUTPUT VOLTAGE vs. LOAD CURRENT<br>100 (VOUT = 2.5V, PFM MODE) toc07 100 (VOUT = 3.3V, PFM MODE) toc08 0.904 (VOUT = 0.9V, PWM MODE) toc09<br>90 VIN = 5V 90 VIN = 5.5V 0.903<br>80 80<br>0.902<br>70 70 VIN = 12V<br>60 60 0.901<br>50 50 0.900<br>40 40<br>VIN = 20V VIN = 12V VIN = 20V 0.899<br>30 30<br>20 VIN = 12V 20 0.898 VIN = 5V<br>10 10 0.897<br>0 0 0.896<br>1 10 100 1 10 100 0 30 60 90 120 150 180 210 240 270 300<br>LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA)<br>EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%)<br>EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%)<br>EFFICIENCY (%) EFFICIENCY (%)<br>OUTPUT  VOLTAGE (V)<br>**----- End of picture text -----**<br>


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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Operating Characteristics (continued)** 

(VIN = VEN/UVLO = 12V, VGND = 0V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted. The circuit values for different output-voltage applications are as in Table 1, unless otherwise noted.) 

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OUTPUT VOLTAGE vs. LOAD CURRENT OUTPUT VOLTAGE vs. LOAD CURRENT OUTPUT VOLTAGE vs. LOAD CURRENT<br>(VOUT = 1.5V, PWM MODE) (VOUT = 2.5V, PWM MODE) (VOUT = 3.3V, PWM MODE)<br>toc10 toc11 toc12<br>1.508 TTTTTIIITI I 2.523 ee 3.298 Piet EE EE Ey<br>2.514<br>1.504 VIN = 5V VIN = 5V 3.295 VIN = 5.5V VIN = 12V<br>VIN = 12V 2.505<br>1.500 FEF jy) PEE P HH  | 3.292 Athy eH<br>ty TT 2.496 B E E ERREEB GREE<br>1.496 3.289<br>2.487<br>1.492 tt VIN = 20V 2.478 SESSER000 VIN = 20V VIN = 12V 3.286 {TT VIN = 20V CATS<br>1.4881.484 PETPCCP 2.4692.460 PETPCCP TTT 3.2833.280 PPCCP T T<br>0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300<br>LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA)<br>OUTPUT VOLTAGE vs. LOAD CURRENT  OUTPUT VOLTAGE vs. LOAD CURRENT  OUTPUT VOLTAGE vs. LOAD CURRENT<br>(VOUT = 0.9V, PFM MODE) toc13 1.55 (VOUT = 1.5V, PFM MODE) toc14 (VOUT = 2.5V, PFM MODE) toc15<br>2.58<br>0.934<br>PTT TT ey yy 1.54 FT] i tL LLL c H+<br>0.925 VIN = 5V VIN = 5V 2.56<br>1.53<br>P OT VIN = 12V ) ee VIN = 20V e 2.54 po<br>0.916 re |  I 1.52 4 2.52 VIN = 5V<br>0.907 aL | 1.51 PN VIN = 12V S ot VIN = 20V<br>PPSRCCCEEE} «= PR R} 2.50 RAH, |<br>0.898 1.50 2.48 VIN = 12V<br>0.889 PCACPITT TTT 1.49 |SEA| |  UHEREEE 2.46 POR PT<br>0.880 PCCP 1.48 PCCP 2.44 PCCP<br>0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300 0 30 60 90 120 150 180 210 240 270 300<br>LOAD CURRENT (mA) LOAD CURRENT (mA) LOAD CURRENT (mA)<br>OUTPUT VOLTAGE vs. LOAD CURRENT  OUTPUT-VOLTAGE RIPPLE OUTPUT-VOLTAGE RIPPLE<br>(VOUT = 3.3V, PFM MODE) (VIN = 12V, VOUT = 1.5V FULL LOAD, PWM MODE) (VIN = 12V, VOUT = 3.3V FULL LOAD, PWM MODE)<br>toc16 toc17 toc18<br>3.39 P| | | | | ft ft tt v i rf<br>3.37 POCA | :<br>VIN = 5.5V<br>3.35 C EC E | |<br>3.33 ea | |<br>VIN = 20V VOUT (AC) 10mV/div VOUT (AC) 10mV/div<br>3.31<br>ShGeennnne Paine VAAADAANIA<br>3.29 PORE<br>3.27 VIN = 12V<br>3.25 SanPCO a/Q unnnCorr :|: :||<br>0 30 60 90 120 150 180 210 240 270 300 2µs/div 2µs/div<br>LOAD CURRENT (mA)<br>OUTPUT  VOLTAGE (V) OUTPUT  VOLTAGE (V) OUTPUT  VOLTAGE (V)<br>OUTPUT  VOLTAGE (V) OUTPUT  VOLTAGE (V) OUTPUT  VOLTAGE (V)<br>OUTPUT  VOLTAGE (V)<br>**----- End of picture text -----**<br>


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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Operating Characteristics (continued)** 

(VIN = VEN/UVLO = 12V, VGND = 0V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted. The circuit values for different output-voltage applications are as in Table 1, unless otherwise noted.) 

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LOAD TRANSIENT RESPONSE<br>INPUT-VOLTAGE RIPPLE, INPUT-VOLTAGE RIPPLE (VIN = 12V, VOUT = 1.5V, PFM MODE)<br>(VIN = 12V, VOUT = 1.5V FULL LOAD, PWM MODE) toc19 (VIN = 12V, VOUT = 3.3V FULL LOAD, PWM MODE) toc20 (LOAD CURRENT STEPPED FROM 5mA to 150 toc21 mA)<br>VOUT (AC)<br>20mV/div<br>VIN (AC) 100mV/div VIN (AC) 100mV/div<br>IOUT 100mA/div<br>2µs/div 2µs/div 100µs/div<br>LOAD TRANSIENT RESPONSE LOAD TRANSIENT RESPONSE LOAD TRANSIENT RESPONSE<br>(VIN = 12V, VOUT = 1.5V, MODE = PWM) (VIN = 12V, VOUT = 3.3V, PFM MODE) (VIN = 12V, VOUT = 3.3V, PWM MODE)<br>(LOAD CURRENT STEPPED FROM 150mA TO 300mA) (LOAD CURRENT STEPPED FROM 5mA TO 150mA) (LOAD CURRENT STEPPED FROM 150mA TO 300mA)<br>toc22 toc23 toc24<br>VOUT (AC) 20mV/div 100mV/div VOUT (AC) 50mV/div<br>VOUT (AC)<br>100mA/div 100mA/div<br>IOUT IOUT 100mA/div IOUT<br>Hee<br>100µs/div 100µs/div 100µs/div<br>Pre fay A r e<br>STARTUP THROUGH ENABLE SHUTDOWN THROUGH ENABLE STARTUP THROUGH ENABLE<br>(VIN = 12V, VOUT = 1.5V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 1.5V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)<br>toc25 toc26 toc27<br>5V/div 5V/div<br>EN/UVLO EN/UVLO 5V/div EN/UVLO<br>LX 10V/div LX 10V/div LX 10V/div<br>1V/div 2V/div<br>VOUT 5V/div VOUT 1V/div VOUT 5V/div<br>RESET RESET 5V/div RESET<br>o s a S<br>1ms/div 100µs/div 1ms/div<br>**----- End of picture text -----**<br>


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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Operating Characteristics (continued)** 

(VIN = VEN/UVLO = 12V, VGND = 0V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted. The circuit values for different output-voltage applications are as in Table 1, unless otherwise noted.) 

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SHUTDOWN THROUGH ENABLE STARTUP THROUGH ENABLE - 2V PREBIAS<br>(VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 3.3V, PWM MODE, NO LOAD)<br>toc28 toc29<br>5V/div<br>EN/UVLO 5V/div EN/UVLO<br>LX 10V/div<br>LX 20V/div<br>2V/div<br>VOUT 2V/div VOUT 5V/div<br>RESET 5V/div RESET<br>*<br>100µs/div 1ms/div<br>**----- End of picture text -----**<br>


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STARTUP THROUGH ENABLE - 2V PREBIAS STARTUP THROUGH VIN<br>(VIN = 12V, VOUT = 3.3V, PFM MODE, NO LOAD)IN = 12V, VOUT = 3.3V, PFM MODE, NO LOAD) = 12V, VOUT = 3.3V, PFM MODE, NO LOAD)OUT = 3.3V, PFM MODE, NO LOAD) = 3.3V, PFM MODE, NO LOAD) (VIN = 12V, VOUT = 1.5V, PWM MODE, FULL LOAD)<br>toc30 toc31<br>10V/div<br>5V/div<br>VIN<br>LX 20V/div LX 10V/div<br>2V/div<br>500mV/div<br>2V/div<br>OUT 5V/div VCC<br>VOUT<br>=<br>1ms/div 1ms/div<br>SHUTDOWN THROUGH VIN STARTUP THROUGH VIN<br>(VIN = 12V, VOUT = 1.5V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)<br>toc32 toc33<br>10V/div<br>VIN 10V/div VIN<br>LX 10V/div LX 10V/div<br>2V/div<br>2V/div<br>VCC 2V/div VCC<br>VOUT 500mV/div VOUT<br>=<br>1ms/div 1ms/div<br>**----- End of picture text -----**<br>


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STARTUP THROUGH ENABLE - 2V PREBIAS<br>(VIN = 12V, VOUT = 3.3V, PFM MODE, NO LOAD)IN = 12V, VOUT = 3.3V, PFM MODE, NO LOAD) = 12V, VOUT = 3.3V, PFM MODE, NO LOAD)OUT = 3.3V, PFM MODE, NO LOAD) = 3.3V, PFM MODE, NO LOAD)<br>toc30<br>5V/div<br>EN/UVLO<br>LX 20V/div<br>2V/div<br>VOUT 5V/div<br>RESET<br>=<br>1ms/div<br>**----- End of picture text -----**<br>


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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Operating Characteristics (continued)** 

(VIN = VEN/UVLO = 12V, VGND = 0V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to GND, unless otherwise noted. The circuit values for different output-voltage applications are as in Table 1, unless otherwise noted.) 

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SHUTDOWN THROUGH VIN OUTPUT SHORT IN STEADY STATE<br>(VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)<br>toc34 toc35<br>5V/div<br>VIN 10V/div SHORT<br>LX 10V/div<br>VOUT 2V/div<br>LX 20V/div<br>VCC 2V/div<br>VOUT 2V/div IOUT 200mA/div<br>a<br>1ms/div 20ms/div<br>**----- End of picture text -----**<br>


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OUTPUT SHORT DURING STARTUP BODE PLOT<br>(VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD) (VIN = 12V, VOUT = 1.5V, PWM MODE, FULL LOAD)<br>toc36 80 toc37 90<br>— | 10V/div 60 Uo<br>60<br>VIN ae 40 SoA PHASE<br>30<br>20<br>| PSST THTTIN<br>VOUT | 2V/div 0 S S 0<br>GAIN<br>-20<br>-30<br>LX C opp 10V/div -40 ee s<br>IOUT EERE 200mA/div -60 a CROSSOVER FREQUENCY = 59.55kHzPHASE MARGIN = 51.03° -60<br>-80 -90<br>nen a 20ms/div EE RAEDERS 1k coe 10k iM 100k<br>FREQUENCY (Hz)<br>BODE PLOT OUTPUT CURRENT<br>(VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)IN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD) = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)OUT = 3.3V, PWM MODE, FULL LOAD) = 3.3V, PWM MODE, FULL LOAD) vs. AMBIENT TEMPERATURE<br>80 toc38 90 350 toc39<br>60 Poo 60 300 TTT T_<br>40 CSS PHASE ARSIII 250 TVS<br>30<br>20<br>PPT TTS 200 en<br>0 O SEE 0 ae<br>-20 C c GAIN 150 — VOUT = 3.3V “\_|<br>-30<br>-40 C oAi 100 — < VOUT = 2.5V pJA<br>-60 CROSSOVER FREQUENCY = 46.25kHz -60 50<br>PHASE MARGIN = 56.7°<br>-80 peer mil -90 0 Pe e e n<br>1k 10k 100k 50 70 90 110 130<br>FREQUENCY (Hz) AMBIENT TEMPERATURE ( ° C)<br>) °<br>GAIN (dB) PHASE MARGIN (<br>) ° PHASE MARGIN (<br>OUTPUT CURRENT (mA)<br>**----- End of picture text -----**<br>


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BODE PLOT<br>(VIN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)IN = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD) = 12V, VOUT = 3.3V, PWM MODE, FULL LOAD)OUT = 3.3V, PWM MODE, FULL LOAD) = 3.3V, PWM MODE, FULL LOAD)<br>80 toc38 90<br>60<br>Poo 60<br>40 CSS PHASE ARSIII<br>30<br>20<br>PPT TTS<br>0 O SEE 0<br>GAIN<br>-20 C c<br>-30<br>Ai<br>-40 C oAi<br>-60<br>-60 CROSSOVER FREQUENCY = 46.25kHz<br>PHASE MARGIN = 56.7°<br>-80 peer mil -90<br>1k 10k 100k<br>FREQUENCY (Hz)<br>) °<br>GAIN (dB)<br>PHASE MARGIN (<br>**----- End of picture text -----**<br>


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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Pin Configuration** 

**==> picture [505 x 255] intentionally omitted <==**

**----- Start of picture text -----**<br>
TOP VIEW<br>+<br>LX 1 10 VIN<br>GND 2 MAXM17903 9 VIN<br>RESET 3 8 EN/UVLO<br>MODE 4 7 VCC<br>OUT 5 6 FB<br>‘+’ INDICATES PIN 1 OF THE MODULE<br>**----- End of picture text -----**<br>


## **Pin Description** 

|**PIN**|**NAME**|**FUNCTION**|
|---|---|---|
|1|LX|Switching Node of the Inductor. No external connection to this pin.|
|2|GND|Ground Pin. Connect GND to the ground plane. See the_PCB Layout Guidelines_ section for more details.<br>Refer to the MAXM17903 EV kit for a sample layout.|
|3|RESET|Open-Drain Power-Good Output. Pull upRESETto an external power supply with an external resistor.<br>RESETgoes low if FB drops below 92% of its set value.RESETgoes high impedance 2ms after FB rises<br>above 95.5% of its set value. See the_Electrical Characteristics_ table for threshold values.|
|4|MODE|PFM/PWM Mode-Selection Input. Connect MODE to GND to enable fxed-frequency PWM operation at all<br>loads. Leave MODE unconnected for PFM operation at light load.|
|5|OUT|Module Output Pin. Connect a capacitor from OUT to GND. See the _PCB Layout Guidelines_ section for<br>more details.|
|6|FB|Output Feedback Connection. Connect FB to a resistor-divider between OUT and GND to set the output<br>voltage.|
|7|VCC|Internal LDO Power Output. Bypass VCCto GND with a minimum 1µF ceramic capacitor.|
|8|EN/UVLO|Active-High, Enable/Undervoltage-Detection Input. Pull EN/UVLO to GND to disable the module output.<br>Connect EN/UVLO to VINfor always-on operation. Connect a resistor-divider between VIN, EN/UVLO, and<br>GND to program the input voltage at which the module turns on.|
|9–10|VIN|Power-Supply Input. Connect the VINpins together. Decouple to GND with a capacitor; place the capacitor<br>close to the VINand GND pins. See Table 1for more details.|



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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Functional Diagrams Internal Diagram** 

**==> picture [506 x 517] intentionally omitted <==**

**----- Start of picture text -----**<br>
MAXM17903<br>VCC VIN<br>LDO<br>HIGH-SIDE<br>DRIVER<br>EN/UVLO + LX<br>-<br>1.215V 33µH<br>OUT<br>PEAK<br>CURRENT-MODE<br>OSCILLATOR<br>CONTROLLER<br>LOW-SIDE<br>DRIVER<br>SOFT-START GND<br>MODE<br>MODE SLOPE<br>SELECTION<br>COMPENSATION<br>LOGIC<br>RESET<br>FB RESET<br>LOGIC<br>**----- End of picture text -----**<br>


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## MAXM17903 

## **Detailed Description** 

The MAXM17903 module is a high-voltage, syn chronous step-down DC-DC module with integrated MOSFETs and inductor, that operates over a wide 4.5V to 24V inputvoltage range. The module delivers an output current up to 300mA over a programmable output-voltage range of 0.9V to 3.3V. When EN/UVLO and VCC UVLO are ascertained, an internal power-up sequence ramps up the error-amplifier reference, resulting in an output-voltage soft-start. 

The FB pin monitors the output voltage through a resistordivider. The RESET pin transitions to a high-impedance state 2ms after the output voltage reaches 95.5% of regulation. The devices select either PFM or forcedPWM mode depending on the state of the MODE pin at power-up. By pulling the EN/UVLO pin to low, the devices enter shutdown mode and consumes only 2.2μA (typ) of standby current. 

The module uses an internally compensated, fixed-frequency, current-mode control scheme. On the rising edge of an internal clock, the high-side pMOSFET turns on. An internal error amplifier compares the feedback voltage to a fixed internal refer ence voltage and generates an error voltage. The error voltage is compared to a sum of the current-sense voltage and a slope-compensation voltage by a PWM comparator to set the on-time. During the on-time of the pMOSFET, the inductor current ramps up. For the remainder of the switching period (off-time), the pMOSFET is kept off and the low-side nMOSFET turns on. During the off-time, the inductor releases the stored energy as the inductor current ramps down, providing current to the output. Under over load conditions, the cycle-by-cycle current-limit feature limits the inductor peak current by turning off the high-side pMOSFET and turning on the low-side nMOSFET. 

## **Mode Selection (MODE)** 

The logic state of the MODE pin is latched after VCC and EN/UVLO voltages exceed respective UVLO rising thresholds and all internal voltages are ready to allow LX switching. If the MODE pin is unconnected at power-up, the part operates in PFM mode at light loads. If the MODE pin is grounded at power-up, the part operates in constant-frequency PWM mode at all loads. State changes on the MODE pin are ignored during normal operation. 

## **PWM Operation** 

In PWM mode, the module output current is allowed to go negative. PWM operation is useful in frequency sensitive applications and provides fixed switching frequency operation at all loads. However, PWM-mode of operation 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

gives lower efficiency at light loads compared to PFMmode of operation. 

## **PFM Operation** 

PFM mode operation disables negative output current from the module, and skips pulses at light loads for better efficiency. In PFM mode, the module output current is forced to a fixed peak of 130mA in every clock cycle until the output voltage rises to 102.3% of the nominal value. Once the output voltage reaches 102.3% of the nominal value, the high-side switch is turned off and the low-side switch is turned on. Once the module output current hits zero cross, LX goes to a high-impedance state and the module enters hibernate operation until the load current discharges the output voltage to 101.1% of the nominal value. Most of the internal blocks are turned off in hibernate operation to save quiescent current. When the output voltage falls below 101.1% of the nominal value, the module comes out of hibernate operation, turns on all internal blocks, and commences the process of delivering pulses of energy until the output voltage reaches 102.3% of the nominal value. The module naturally comes out of PFM mode and serves load requirements when the module output demands more than 130mA peak. The advantage of PFM mode is higher efficiency at light loads because of lower quiescent current drawn from supply. 

## **Internal 5V Regulator** 

An internal regulator provides a 5V nominal supply to power the internal functions and to drive the power MOSFETs. The output of the linear regulator (VCC) should be bypassed with a 1μF ceramic capacitor to GND. The VCC regulator dropout voltage is typically 150mV. An undervoltage lockout circuit that disables the buck converter when VCC falls below 3.8V (typ). The 400mV, VCC-UVLO hysteresis prevents chattering on power-up and power-down. 

## **Enable/Undervoltage Lockout (EN/UVLO), Soft-Start** 

When EN/UVLO voltage is above 1.215V (typ), the device’s internal error-amplifier reference voltage starts to ramp up. The duration of the soft-start ramp is 4.1ms (typ), allowing a smooth increase of the output voltage. Driving EN/UVLO low disables both power MOSFETs, as well as other internal circuitry, and reduces VIN quiescent current to below 2.2μA. EN/UVLO can be used as an input-voltage UVLO adjustment input. An external voltage-divider between VIN and EN/UVLO to GND adjusts the input voltage at which the device turns on or turns off. If input UVLO programming is not desired, connect EN/ UVLO to VIN (see the _Electrical Characteristics_ table for EN/UVLO rising and falling threshold voltages). 

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## MAXM17903 

## **RESET Output ( RESET )** 

The device includes an open-drain RESET output to monitor the output voltage. RESET goes high impedance 2ms after the output rises above 95.5% of its nominal set value and pulls low when the output voltage falls below 92% of the set nominal regulated voltage. RESET asserts low during the hiccup timeout period. 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

**==> picture [195 x 27] intentionally omitted <==**

**==> picture [117 x 26] intentionally omitted <==**

## **Startup into a Prebiased Output** 

The device is capable of soft-start into a prebiased output, without discharging the output capacitor in both the PFM and forced-PWM modes. Such a feature is useful in applications where digital integrated circuits with multiple rails are powered. 

## **Overcurrent Protection (OCP)/Hiccup Mode** 

The device is provided with a robust overcurrent protection (OCP) scheme that protects the device under overload and output short-circuit conditions. When the device detects either overcurrent, or if the FB node goes below 64.5% of its nominal regulation threshold, the module enters hiccup mode of operation. In hiccup mode, the converter is protected by suspending switching for a hiccup timeout period of 131ms (typ). Once the hiccup timeout period expires, soft-start is attempted again. Hiccup mode of operation ensures low power dissipation under output short-circuit conditions. The device exits Hiccup mode, if the overcurrent condition is removed or, if input power or EN/UVLO is cycled. 

## **Thermal Overload Protection** 

Thermal overload protection limits the total power dissipation in the device. When the junction temperature exceeds +166°C, an on-chip thermal sensor shuts down the device, turns off the internal power MOSFETs, allowing the device to cool down. The thermal sensor turns the device on after the junction temperature cools by 10°C. 

## **Applications Information** 

## **Input-Voltage Range** 

The minimum and maximum operating input voltages for a given output voltage should be calculated as follows: 

where: 

VOUT = Steady-state output voltage, 

IOUT  = Maximum load current, 

fSW = Worst-case switching frequency(535000 Hz), 

DMAX  = Maximum duty cycle (0.89), 

tON(MIN) = Worst-case minimum controllable switch ontime (130ns). 

Also, for duty cycle > 0.5; 

VIN(MIN) > ((4.27 × VOUT) − 9.76) 

## **Selection of Input Capacitor** 

The input filter capacitor reduces peak currents drawn from the power source and reduces noise and voltage ripple on the input caused by the converter’s switching. 

The input capacitor RMS current requirement (IRMS) is defined by the following equation: 

**==> picture [186 x 29] intentionally omitted <==**

where, IOUT(MAX) is the maximum load current. IRMS has a maximum value when the input voltage equals twice the output voltage (VIN = 2 x VOUT). So, 

**==> picture [104 x 24] intentionally omitted <==**

Choose an input capacitor that exhibits less than a +10°C temperature rise at the RMS input current for optimal long-term reliability. Use low-ESR ceramic capacitors with high-ripple-current capability at the input. X7R capacitors are recommended in industrial applications for their 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

temperature stability. Calculate the input capacitance using the following equation: 

**==> picture [161 x 27] intentionally omitted <==**

where: 

DMAX = Maximum duty cycle(0.89), fSW = Switching frequency, ΔVIN = Allowable input-voltage ripple. 

## **Selection of Output Capacitor** 

Small ceramic X7R-grade capacitors are sufficient and recommended for output-voltage generation. The output capacitor has two functions. It provides smooth voltage and, stores sufficient energy to support the output voltage under load transient conditions and stabilizes the device’s internal control loop. Usually the output capacitor is sized to support a step load of 50% of the maximum output current in the application, such that the output-voltage deviation is less than 3%. Required output capacitance can be calculated from the following equation: 

**==> picture [65 x 24] intentionally omitted <==**

where COUT is the output capacitance in μF and VOUT is the output voltage. Derating of ceramic capacitors with DC-voltage must be considered while selecting the output capacitor. 

## **Setting the Input Undervoltage-Lockout Level** 

The devices offer an adjustable input undervoltage lockout level. Set the voltage at which the device turns on with a resistive voltage-divider connected from VIN to GND (see Figure 1). Connect the center node of the divider to EN/UVLO. 

Choose R1 to be 3.3MΩ (max), and then calculate R2 as follows: 

**==> picture [78 x 24] intentionally omitted <==**

where VINU is the voltage at which the device is required to turn on. 

If the EN/UVLO pin is driven from an external signal source, a series resistance of minimum 1kΩ is recommended to be placed between the signal source output and and the EN/UVLO pin, to reduce voltage ringing on the line. 

## **Output-Voltage Setting** 

The MAXM17903 output voltage can be programmed from 0.9V to 5V. Set the output voltage by connecting a resistor-divider from output to FB to GND (see Figure 2). 

Choose R4 less than or equal to 75kΩ and calculate R3 with the following equation: 

**==> picture [91 x 25] intentionally omitted <==**

**==> picture [504 x 155] intentionally omitted <==**

**----- Start of picture text -----**<br>
OUT<br>VIN<br>R3<br>R1 MAXM17903 MAXM17903<br>FB<br>EN/UVLO<br>R4<br>R2<br>**----- End of picture text -----**<br>


_Figure 1. Adjustable EN/UVLO Network_ 

_Figure 2. Setting the Output Voltage_ 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Table 1. Selection of Components** 

|**VIN(MIN)**<br>**(V)**|**VIN(MAX)**<br>**(V)**|**VOUT* **<br>**(V)**|**CIN**|**COUT**|**R3**<br>**(kΩ)**|**R4**<br>**(kΩ)**|**IAVG_LIMIT**<br>**(A)**|
|---|---|---|---|---|---|---|---|
|4.5|12.5|0.9|Use 1 x 1µF 0805 25V<br>(Murata GRM219R71E105KA88D)|1 x 47µF 1210 6.3V<br>(Murata GRM32ER70J476KE20L)|SHORT|OPEN|0.53|
|4.5|14|1|Use 1 x 1µF 0805 25V<br>(Murata GRM219R71E105KA88D)|1 x 47µF 1210 6.3V<br>(Murata GRM32ER70J476KE20L)|8.33|75|0.53|
|4.5|17|1.2|Use 1 x 1µF 0805 25V<br>(Murata GRM219R71E105KA88D)|1 x 47µF 1210 6.3V<br>(Murata GRM32ER70J476KE20L)|25|75|0.52|
|4.5|21.5|1.5|Use 1 x 1µF 0805 25V<br>(Murata GRM219R71E105KA88D)|1 x 22µF 1206 6.3V<br>(Murata GRM31CR70J226KE19L)|50|75|0.51|
|4.5|24|1.8|Use 1 x 1µF 0805 50V<br>(Murata GRM21BR711105KA12L)|1 x 22µF 1206 6.3V<br>(Murata GRM31CR70J226KE19L)|75|75|0.50|
|4.5|24|2.5|Use 1 x 1µF 0805 50V<br>(Murata GRM21BR711105KA12L)|1 x 22µF 1206 6.3V<br>(Murata GRM31CR70J226KE19L)|133|75|0.48|
|5.5|24|3.3|Use 1 x 1µF 0805 50V<br>(Murata GRM21BR711105KA12L)|1 x 10µF 1206 6.3V<br>(Murata GRM31CR70J106KA01L)|200|75|0.46|



***** _The MAXM17903 has a pulse skip algorithm that allows VOUT to be regulated beyond the VIN(MAX) specified in the above table, up to 21V._ 

## **Power Dissipation** 

The device output current needs to be derated if the device needs to operate in high ambient temperature. The derating curves given in the _Typical Operating Characteristics_ section can be used as a guide. 

## **PCB Layout Guidelines** 

Use the following guidelines for good PCB layout: 

- Keep the input capacitors as close as possible to the IN and GND pins. 

- Keep the output capacitors as close as possible to the OUT and GND pins. 

- Keep the resistive feedback dividers as close as possible to the FB pin. 

- Keep the power traces and load connections short. Refer to the EV kit layout for first-pass success. 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

**==> picture [504 x 456] intentionally omitted <==**

**----- Start of picture text -----**<br>
VIN VOUT<br>VIN OUT<br>CI N MAXM17903 COUT<br>R1 R3<br>RESET<br>EN/UVLO FB<br>VCC LX<br>R2 R4<br>CVC C<br>GND MODE<br>CIN<br>GND PLANE VIN PLANE<br>+<br>LX 1 10 VIN<br>GND 2 MAXM17903 9 VIN<br>R1<br>RESET 3 8 EN/UVLO<br>MODE 4 7 VCC R2<br>COUT<br>OUT 5 6<br>CVCC<br>FB<br>VOUTPLANE R3 R4 GND PLANE<br>**----- End of picture text -----**<br>


_Figure 3. Layout Guidelines_ 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Typical Application Circuits** 

## **Typical Application circuit for 3.3V Output** 

**==> picture [504 x 254] intentionally omitted <==**

**----- Start of picture text -----**<br>
5.5V TO 21V 3.3V, 300mA<br>VIN OUT<br>C1 C2<br>1µF EN/UVLO GND 10µF R1<br>200kΩ<br>MAXM17903<br>RESET FB<br>VCC LX<br>R2<br>C3 75kΩ<br>MODE<br>1µF<br>MODE = GND FOR PWM<br>MODE = OPEN FOR PFM<br>C1 = MURATA 1µF/X7R/25V/0805 (GRM219R71E105KA88D)<br>C2 = MURATA 10µF/X7R/6.3V/1206 (GRM31CR70J106KA01L)<br>C3 = MURATA 1µF/X7R/6.3V/0603 (GRM188R70J105K)<br>**----- End of picture text -----**<br>


## **Typical Application circuit for 1.5V output** 

**==> picture [256 x 185] intentionally omitted <==**

**----- Start of picture text -----**<br>
4.5V TO 21V 1.5V, 300mA<br>VIN OUT<br>C1 C2<br>1µF EN/UVLO GND 22µF R1<br>50kΩ<br>MAXM17903<br>RESET FB<br>VCC LX<br>R2<br>C3 75kΩ<br>MODE<br>1µF<br>MODE = GND FOR PWM<br>MODE = OPEN FOR PFM<br>C1 = MURATA 1µF/X7R/25V/0805 (GRM219R71E105KA88D)<br>**----- End of picture text -----**<br>


C2 = MURATA 22µF/X7R/6.3V/1206 (GRM31CR70J226KE19L) 

C3 = MURATA 1µF/X7R/6.3V/0603 (GRM188R70J105K) 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Ordering Information** 

|**PART**<br>**NUMBER**|**TEMP**<br>**RANGE**|**PIN-PACKAGE**|
|---|---|---|
|MAXM17903AMB+|-40°C to +125°C|10-pin uSLIC|
|MAXM17903AMB+T|-40°C to +125°C|10-pin uSLIC|



_+ Denotes a lead(Pb)-free/RoHS-compliant package._ 

_T Denotes tape-and-reel._ 

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## MAXM17903 

## 4.5V to 24V, 300mA Compact Step-Down Power Module 

## **Revision History** 

|**Revision**|**History**|||
|---|---|---|---|
|**REVISION**<br>**NUMBER**|**REVISION**<br>**DATE**|**DESCRIPTION**|**PAGES**<br>**CHANGED**|
|0|12/17|Initial release|—|



For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. 

_Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance._ 

© 2017 Maxim Integrated Products, Inc. │ 18 

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