GS-R400/2 Family
SMALL SIZE STEP-DOWN
SWITCHING REGULATOR FAMILY
June 1994 1/3
SELECTI ON 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% 9 to 40 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+4 to 40 25 to 100 2 to 6 20 to 80 80 to 90 Progr. output voltage
Note : Line regulation is measured at Iout=1A.
Load regul ati on is mea sured 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
4A max output current
40V max input voltage
4V ma x dro p-o ut voltage
Soft start
Non-latching short circuit protection
Crow-b ar ou tput o ve rvolta ge protection
DESCRIPTION
The GS-R400/2 series is a family of small sized
high current, high voltage step-down switching
regulators.
The integral heatsink allows a large power handling
capability and it provides also an effective shielding
to minimize EMI.
ABSOLUTE MAXIMUM 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
Pin 5 GS-R400V/2 only
Dimens ions i n mm B ottom v iew
2/3
ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise specified)
Symbol Par ameter Test Conditions Min Typ Max Unit
∆Vo/∆TTemperature Stability Vi = Vo+8V Io = 1A 0.2/0.6 mV/°C
IoOutput Current Vi = Vo+8V 0.1 4 A
IoL Current Limit Vi = Vo+8V 58A
I
isc Average Input Current Vi = 40V Output Shorted 0.1 0.2 A
fsSwitching Frequency Io = 1A 100 kHz
SVR Supply V oltage Rejection fo = 100Hz Io = 1A 4/12 mV/V
VrRipple V oltage Io = 1A 25/100 mVpp
tss Soft Star t Tim e 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 A re sistor (<10kΩ) connected between this pin and pin 4 sets the + output voltage of the
GS-R400V/2.
G S- R 400/ 2 FAM I LY
3/3
USER NOTES
Input Voltage
The recommended operating maximum DC input
voltag e is 40V inclusive of the ripple voltage .
Case Grounding
The module case is internally connected to pin 2
and pin 3.
The PCB area below the module can be used as an
effective sixth side shield against EMI.
Thermal Characteristics
The case-to-ambient thermal resistance of all the
GS-R400/2 modules is about 8°C/W. This produces
a 32°C temperature increase of the module surface
for 4W of int ern al power di s sip at ion .
Dep en ding on the am bie nt te mp era tu re 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
stabi lity. T his capacito r canno t hand le larg e values
of high fre quen cy rip ple cu rrent an d it can be p er-
manently damaged if the primary energy source
impedance is not adequate.
The use of an external low ESR, high ripple current
ca pa citor loca ted as cl ose the m odule as possi b le
is recomm en de d.
Suitable capacitors should have a RMS current
capability of 2.5 ARMS with a working voltage of 50
VDC and an ESR o f 0,1Ω at 100kHz. When space
is a lim itation a 22µF ceram ic m ultila ye r capa citor
must be connected to the module input pins.
Output Voltage Programming
The GS-R400V/2 output voltage is programmed by
using a resistor.
The resistor must be located very close the mod ule
and the PCB layou t must min im ize in jected noise.
The va lue of th e re sisto r is ca lcula te d by usi ng the
following formula:
Rv = 2.6 7
Vo
5.1− 1
kΩ
Vo ca n be ad ju sted be twee n 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
automatically disabled. After a fixed time the module
starts again in a soft mode. The cycle is repeated
un til the sho rt circuit conditio n is rem oved .
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 Mi croelectroni cs assumes no respons ibil ity for the
consequences of use of such information nor for any infringement of patents or other r ights of third parties wh ich may result from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specific ation menti oned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Mic roel ectro nic s produ cts a re no t a utho rize d f or u se as crit ic al c ompo nent s in l ife support de vi ces o r syst ems wi thou t e xpress
written approval of SGS-THOMSON Microelectronics.
© 1994 SGS-THOMSON Microel ectronics – All Rights Reserved
SGS-THOMSON Microelectronics GROUP OF COMPANIES
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G S- R 400/ 2 FAM I LY
