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Key Features:  20A Output Current  Wide 6V - 14V Input Range  Effi ciency to 94%  EN 60950 Approved (UL)  Sequencing Capability  Compact SIP Case  Short Circuit Protected  Thermal Shutdown  Remote On/Off Control  Industry Standard Footprint SRS20A-12W Miniature, Non-isolated 20A Output, Switching POL Regulators Series MicroPower Direct

292 Page Street

Stoughton, MA 02072 USA T: (781) 344-8226 F: (781) 344-8481 E: sales@micropowerdirect.com W: www.micropowerdirect.com Electrical Specifi cations Specifi cations typical @ +25°C, nominal input voltage & rated output current, unless otherwise noted. Specifi cations subject to change without notice. www.micropowerdirect.com Input Parameter Conditions Min. Typ. Max. Units Input Voltage Range 6.0 12.0 14.0 VDC Under Voltage Lockout, Power Up Turn On Voltage Threshold 5.0 VDCTurn Off Voltage Threshold 4.0 Lockout Hysteresis Voltage 1.0 Maximum Input Current IOUT = 100%, VIn = 0 to 14 VDC 19.0 A Off Input Current Input Idle Current 10 mA Input Filter Capacitive Input Refl ected Ripple Current See Note 1 220 mA P-P Output Parameter Conditions Min. Typ. Max. Units Output Voltage/Current See Model Selection Guide Output Voltage Tolerance ±1.5 % Line Regulation VIN = Min to Max ±0.2 % Load Regulation IOUT = 0% to 100% ±0.5 % Ripple & Noise (20 MHz) See Note 2 75 mV P-P 30 mV RMS Transient Recovery Time, See Note 3 50% Load Change 200 µSec Temperature Coeffi cient ±0.03 %/°C Power Good Signal, See Note 4 TTL High Signal When V OUT = 90% to 110% Short Circuit Protection Continuous (Hiccup Mode) Over Temperature Protection See Note 5 130 °C Overload Protection See Note 6 150 % General Parameter Conditions Min. Typ. Max. Units Isolation Voltage Not Isolated Switching Frequency Fixed 300 kHz Remote On/Off, See Note 7 Parameter Conditions Min. Typ. Max. Units Unit On Logic High Open or VIN Unit Off Logic Low 0.0 0.4 VDC On/Off Current VON/VOFF = 0.0V 1 mA Environmental Parameter Conditions Min. Typ. Max. Units Operating Temperature Range Ambient -40 +25 +85 °C Storage Temperature Range -55 +125 °C Cooling Free Air Convection (See Derating Curves) Humidity RH, Non-condensing 93 % Physical Weight 0.357 Oz (11.0g) Reliability Specifi cations Parameter Conditions Min. Typ. Max. Units MTBF MIL HDBK 217F , 25°C, Gnd Benign 900 kHours Safety Standards UL 60950, EN 60950

Notes: 1. Measured over a bandwidth of 5 Hz to 20 MHz using a 1 µH inductor. 2. Output ripple is measured at 20 MHz bandwidth using a 1.0 µF ceramic capacitor and a 10 µF tantalum capacitor connected in parallel as close to the output terminals as possible. 3. Transient recovery is measured to within a 200 mV error band for a 50% load change. 4. The “Power Good” signal is optional. To include this, add a “P” to the product number (SRS20A-12W-5.0P). If it is not included, then pin 6 is not installed. 5. These units include a non-latching over temperature protection circuit. If the temperature exceeds approximately 130°C at the monitored “hot spot”, the unit will be shut down. When the temperature decreases, the unit will automatically restart. See page 3 for temperature measurement information. 6. These units will provide up to 150% of rated current. In the event of an over current fault, the unit will go into hiccup mode until the fault is removed. 7. Standard units feature an active high remote control input. See the note and diagram at right. 8. These units do not include an internal fuse. It is recommended that an external slow-blow fuse be used with a rating as shown in the table above. 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com Model Number Input Output Effi ciency (%, Typ) Capacitive Load (µF Max) Fuse Rating Slow-Blow (A) Voltage (VDC) Current (mA) Voltage (VDC) Current (A, Max) Current (A, Min)Range Full-Load No-Load SRS20A-12W-5.0 6.0 - 14.0 1,603 40 0.75 20.0 0.0 8,000 25 2,381 50 1.20 84 2,874 50 1.50 87 3,409 50 1.80 88 3,745 60 2.00 89 4,630 65 2.50 90 5,978 75 3.30 92 6.5 - 14.0 8,865 95 5.00 94 Remote On/Off These units include an active high On/OFF control input. The unit is “ON” if the input to the control pin (pin 11) is high; or if the pin is left open (or fl oating). The signal level of the control input is referenced to ground. A recommended drive circuit for the control pin is shown at left. The resistors R 1 & R2 have been added to help reduce pos- sible false triggering of the control input due to leakage currents. Units are available with an active low control input. With this input, the unit will remain off if the con- trol input remains above 2.8 VDC. For more information on the active low option, contact the factory. Notes: Fuse: SRS20A-12W regulators do not include an internal fuse. For safety and protection, a external slow-blow fuse should be placed in the input (+V IN) line. A 25A fuse is recommended. Input Filter: The unit must be connected to a low AC impedance source, and to avoid loop stability issues, the source inductance should also be low. To signifi cantly reduce ripple caused by the switching action of the POL, the SRS20A-12W includes onboard fi ltering. However, adding input capacitors C 1 and C2 will further reduce ripple currents (C1) and high frequency noise spikes (C 2). These capacitors should be placed as close to the input pins as possible (see board layout at right). It is recommended that low ESR (<100 m/H9024) and low ESL ceramic capacitors be used. Recommended values are: C1 C2 33 µF to 250 µF 0.01 µ F Remote ON/OFF: See note above Typical Connection Output Trim: See note on page 4 Remote Sense: The remote sense helps regulate the output voltage at the point of load by minimizing the effects of distribution losses. The voltage between the sense pin (Pin 3) and the point of load should not exceed 500 mV. When using the remote sense function, the output voltage level may rise. Care must be taken not to exceed the maximum rated output power of the regulator. When not in use, the remote sense pin should be tied to the output pin of the regulator. Output Filter: Output fi ltering is not required, but may be used to further reduce output ripple & noise; or to adjust the transient response time of the unit. Care must be taken not to exceed 8,000 µF , the maximum value of output capacitance the unit is rated for. The values given in the connection dia- gram are typical for light fi ltering.

SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 5.0 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 3.3 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 2.5 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 2.0 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 1.8 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 1.5 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 1.2 VDC SRS20A-12W-5.0 - VIN = 12 VDC, VOUT = 0.75 VDC Temperature Measurement Derating Curves These switching regulators may be used in a wide variety of thermal environments, but must be properly cooled to ensure long reliable operation. The derating curves shown above are approximations of the ambient temperature and airfl ow required to maintain the switching regulator temperature below its maximum rating. Airfl ow should move parallel to the long axis of the unit, as shown at left. Proper cooling can be verifi ed by measuring the temperature at pin six of Q 1 (as shown at left). The thermocouple should be mounted approximately 0.5 in. off the unit board. The temperature at this location should not exceed 120°C. MicroPower Direct • 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com

Mechanical Dimensions Pin Description 1 +V Output 2 +V Output

3 Sense

5 Common

6 Power Good (Opt)

7 Common

10 Sequence

11 Trim

12 Remote On/Off

This diagram illustrates a simple board layout for use with the SRS20A-12W series. As recom- mended, external components are placed as close to the unit as possible. To help shield exter- nal circuitry, the ground plane has been extended under the unit. Any signal traces should not be routed underneath the unit (unless they are on a layer under the ground plane) to avoid unwanted noise interference. Notes: All dimensions are typical in inches (mm)

  • Tolerance x.xx = ±0.02 (±0.50) MicroPower Direct We Power Your Success - For Less! 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com This diagram illustrates board la yout for use SRS20A-12W series. A mended, external co m are placed as c lose to as possible. To help shi nal c ircuitry, t he grou has been extended u unit. Any s ignal trac e not be r outed undern unit (unless they are o under the ground plane unwanted noise interfe Suggested Board Layout SRS20A-12W-5.0 SRS20A-12W-5.0 VOUT (VDC) RTRIM (k/H9024)VOUT (VDC) RTRIM (k/H9024) 0.75 Open 2.00 7.417 1.20 22.46 2.50 5.009 1.50 13.05 3.30 3.122 1.80 9.024 5.00 1.472 Output Voltage Trim The required resistor value for various output levels is given in the table above. To calculate the correct value for a different output level, the formula is: , 1,000R V 0 7525 10 500 TRIM OUT = - - Where: RTRIM = The external trim resistor VOUT = The desired output voltage If a trim resistor is not connected, the output is 0.75 VDC. The output voltage level of the SRS20-12W series is adjust- able over a wide range by the simple addition of an external resistor. This trim resistor is connected between the circuit common and the trim input, as shown in the diagram at left. Sequencing The outputs of multiple SRS20A-12W modules may be controled via the sequencing feature. When not using this featur e, the SEQ input should be left open or tied to VIN. Connecting modules (as shown above), allows users to control the timing of the outputs of multiple modules. For proper sequencing, the input voltage is applied to the module. The On/Off input of each module is left open so that the module is on by default. A minimum 10 mS delay (after the input voltage is applied) is required before applying a voltage on the S EQ input. As a voltage is applied to the SEQ input, the module output voltage will track this control voltage (on a one-to-one volt basis) until the set-point voltage level is reached. To achieve a simultaneous shutdown of the modules, the S EQ input voltage is lowered in a controlled manner. The module output voltages will track this input below their set-point voltages on a one-to-one basis. The input voltage must be maintained within specifi ed limits until the tracking and output voltages reach ground potential.