GS-R400/2 Family
SMALL SIZE STEP-DOWN
SWITCHING REGULATOR FAMILY
June 1994 1/3
SELECTION CHART
Type
Ordering
Number
Output
Voltage
(V)
Input
Voltage
(V)
Output
Ripple
(mVpp)
Regulation Efficiency
(%) Notes
Line
(mV/V) Load
(mV/A)
GS-R405/2 5.1 ±2% 9to40 25 2 20 80 Fixed output voltage
GS-R412/2 12.0 ±4% 16 to 40 50 5 40 85 ”
GS-R415/2 15.0 ±4% 19 to 40 65 6 60 87 ”
GS-R424/2 24.0 ±4% 28 to 40 100 6 80 90 ”
GS-R400V/2 5.1 to 24 Vo+4to 40 25 to 100 2 to 6 20 to 80 80 to 90 Progr. output voltage
Note : Lineregulation is measuredat Iout=1A.
Load regulation is measured at Vin=Vo+8V and Iout=0.5 to 1.5A.
Case temperature must be kept below 85°C
FEATURES
MTBF in excess of 500,000 hours
4Amax output current
40V max input voltage
4V max drop-out voltage
Soft start
Non-latching short circuit protection
Crow-bar output overvoltage protection
DESCRIPTION
The GS-R400/2 series is a family of small sized
high current, high voltage step-down switching
regulators.
The integral heatsink allowsalarge powerhandling
capabilityanditprovides alsoaneffectiveshielding
to minimize EMI.
ABSOLUTEMAXIMUM RATINGS
Symbol Parameter Value Unit
ViDC Input Voltage 42 V
IoOutput Current 4A
T
stg Storage Temperature Range – 40 to +105 °C
Tcop Operating Case Temperature Range – 20 to +85 °C
Pin5 GS-R400V/2only
Dimensionsinmm Bottomview
2/3
ELECTRICAL CHARACTERISTICS (TA=25°C unless otherwise specified)
Symbol Parameter Test Conditions Min Typ Max Unit
∆Vo/∆TTemperatureStability Vi=V
o
+8V Io=1A 0.2/0.6 mV/°C
IoOutput Current Vi=V
o
+8V 0.1 4 A
IoL Current Limit Vi=V
o
+8V 58A
I
isc Average Input Current Vi= 40V Output Shorted 0.1 0.2 A
fsSwitching Frequency Io=1A 100 kHz
SVR Supply Voltage Rejection fo= 100Hz Io = 1A 4/12 mV/V
VrRipple Voltage Io=1A 25/100 mVpp
tss Soft Start Time 10/35 ms
tcb Crowbar Delay Time 5µs
Vcth Crowbar Intervention Threshold Vo•1.25 V
Rth Thermal Resistance Case to ambient 8°C/W
CONNECTION DIAGRAM AND MECHANICAL DATA
PIN DESCRIPTION
Pin Function Description
1+ Input DC input voltage. Recommended maximum voltage is 40V.
2Input GND Return for input voltage source.
3Output GND Return for output current path. Internally connected to pin 2.
4+ Output Regulated DC output voltage.
5Program Aresistor (<10kΩ) connected between this pin and pin 4 setsthe + output voltageof the
GS-R400V/2.
GS-R400/2 FAMILY
3/3
USER NOTES
Input Voltage
The recommended operating maximum DC input
voltage is 40V inclusive of the ripple voltage.
Case Grounding
The module case is internally connected to pin 2
and pin 3.
The PCBarea below the module canbeused asan
effective sixth side shield against EMI.
Thermal Characteristics
The case-to-ambient thermal resistance of all the
GS-R400/2 modules isabout 8°C/W.This produces
a32°C temperature increase of the module surface
for 4W of internal power dissipation.
Depending on the ambient temperature and/or on
the power dissipation, an additional heatsink or
forced ventilation may be required.
Input Impedance
The module has an internal capacitor connected
between the input pins in order to assure PWM
stability. This capacitor cannot handle large values
of high frequency ripple current and it can be per-
manently damaged if the primary energy source
impedance is not adequate.
The use ofan external low ESR, high ripple current
capacitor located as close the module as possible
is recommended.
Suitable capacitors should have a RMS current
capability of 2.5ARMS with a working voltage of 50
VDC and an ESR of 0,1Ωat 100kHz. When space
is a limitation a 22µF ceramic multilayer capacitor
must be connected to the module input pins.
Output Voltage Programming
The GS-R400V/2 outputvoltage is programmed by
using a resistor.
The resistor must be located very close the module
and the PCB layout must minimize injected noise.
The value of the resistor is calculated by using the
following formula:
Rv=2.67
Vo
5.1−1
kΩ
Vocan be adjusted between 5.1 and 24V.
Module Protection
The modules are protected against occasional and
permanent short circuits of the output pins to
ground. During short circuit (when the output cur-
rent exceeds the maximum value) the output is
automaticallydisabled.After afixed timethemodule
starts again in a soft mode. The cycle is repeated
until the short circuit condition is removed.
The module can be permanently damaged if the
case temperature exceeds 85°C
Power Derating Curve
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patentsor otherrights of third parties which may result from its use. No
license is grantedby implicationor otherwise under any patentor patent rightsof SGS-THOMSONMicroelectronics.Specification mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSONMicroelectronics products are not authorized for use ascritical components inlife support devices or systemswithout express
written approval of SGS-THOMSON Microelectronics.
1994SGS-THOMSON Microelectronics – All Rights Reserved
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GS-R400/2 FAMILY
