Model Selection Guide

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.

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Model

Number

Input

Output

Efficiency

(%, Typ)

Capacitive

Load

(µF Max)

Fuse Rating

Slow-Blow

(A)

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

78

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 floating). The signal level

of the control input is referenced

to ground. A recommended drive

circuit for the control pin is shown

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

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 significantly reduce ripple caused by

the switching action of the POL, the SRS20A-12W includes

close to the input pins as possible (see board layout at right).

It is recommended that low ESR (<100 m ) and low ESL

ceramic capacitors be used. Recommended values are:

33 µF to 250 µF

0.01 µF

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 filtering 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 filtering.