GS-R400 Family
20W TO 140W STEP-DOWN
SWITCHING REGULATOR FAMILY
June 1994 1/5
FEATURES
MTBF in excess of 200,000 hours
4A max output current
46V max input voltage
4V ma x dro p-o ut voltage
Soft start
Remote logic inhibit/enable
Remote output voltage sense
Non-latching overload and short circuit protection
Crow-b ar ou tput o ve rvo ltage p rote ct ion
DESCRIPTION
The GS-R400 series is a versatile family of high
current, h igh vo lta ge step-d own swi tchin g vo lta ge
reg ulato rs.
The integral heatsink allows a large power handling
capability and it provides also an effective shielding
to minimize EMI.
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 5.1 ± 2% 9 to 46 25 2 20 70 Fixed output voltage
GS-R412 12.0 ± 4% 16 to 46 50 5 40 80 "
GS-R415 15.0 ± 4% 19 to 46 65 5 60 85 "
GS-R424 24.0 ± 4% 28 to 46 100 6 90 90 "
GS-R405S 5.1 ± 2% 9 to 46 25 2 20 70 Reset output
GS-R400V 5.1 to 40 Vo+4 to 46 25 to 100 6 20 to 90 70 to 90 Progr. output voltage
GS-R400VB 5.1 to 40 Vo+4 to 46 25 to 100 6 20 to 90 70 to 90 Progr. output voltage and
current. Frequency syn chr.
Note: The line regulation is measured at Iout=1A
The load regulat ion is measu red at Vin=Vo+8V and Iout=1 to 3A
For VO ≥ 36V and Io = 4A an ext ernal hea tsi nk or forced ven tilati on are required.
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
ViDC Input Voltage 48 V
Irt*Reset Output Sink Current 20 mA
Tstg Storage Temperature Range – 40 to +105 °C
Tcop Operating Case Temperature Range – 20 to +85 °C
* GS-R405S only
Pin 2 GS-R405S only
Pin 5,6,7 GS-R400VB only
Pin 12 GS-R400V/VB only
Di mens io ns in mm Bottom view
2/5
CONNECTION DIAGRAM AND MECHANICAL DATA
PIN DESCRIPTION
Pin Function Description
1Inhibit The module is disabled by a high logic level applied to this pin.
2Reset Reset output (GS-R405S only).
3+ Input DC input v oltage. Recommended maximum voltage is 46V.
4Input GND Return for input voltage source.
5Oscillator 100kHz oscillator output. To be connected to Sync (pin 6) input if the unit is a master and
left open if it is a slave (GS-R400VB only). See fig. 5.
6Sync Synchronization input. To be connected to the Oscillator output (pin 5) of the master (GS-
R400VB only). See fig. 5.
7Current limiting A resistor (≥ 2.2kΩ) connected from this pin to pin 9 sets the current limiting level
(GS-R400VB only).
8Output GND Return for output current path.
Internally connected to pin 4.
9– Sense Sens es the remote load return. Must be tied to pin 8 when the remote sensing feature is
not used. See fig. 1.
10 + Sense Senses the remote load high side. Must be tied to pin 11 when the remote load sensing
feature is not us ed. See fig. 1.
11 + Output Regulated DC output voltage.
12 Program A resistor (≤ 18kΩ) connected between this pin and pin 10 sets the output voltage
(GS-R400V and GS-R400VB only).
GS-R40 0 F AMI LY
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ELECTRI CAL CHARACTERISTI CS (TA = 25°C unless otherwise specified)
Symbol Parameter Test Conditions Min Typ Max Unit
∆Vo/∆TTemperature Stability Vi = Vo+8V Io = 1A 0.2/1.6 mv/°C
IoOutput Current Vi = Vo+8V 0.2 4 A
IoL Current Limit Vi = Vo+8V 58A
I
isc Average Input Current Vi = 46V Output Shorted 0.1 0.2 A
fsSwitching Fr equency Io = 1A 100 KHz
SVR Supply Voltage Rejection fo = 100Hz Io =1A 4/12 mV/V
VrRipple Voltage Io = 2A 25/150 mVpp
tss Soft Start Time Vi = Vo+8V 10/35 ms
Vinhl Low Inhibit Voltage 0.8 V
Vinhh High Inhibit Voltage 2 5.5 V
Iinhh High Inhibit Input Current Vinh = 5V 500 µA
tcb Crow-bar Delay Time 5µs
Vrh*Reset High Level 5V
V
rl*Reset Low Level Irl = 5mA
Irl = 10mA 0.2
0.4 V
trd*Reset Delay Time 100 ms
Vcth Cr owbar Interv ention Threshold Vo•1.25 V
∆VoTotal Remote
Sens e Compensation 500 mV
Rth Thermal Resistance Case to ambient 5°C/W
* GS-R405S only
USER NOTES
Input Voltage
The recommended operating maximum DC input
voltage is 46V inclusive of the ripple voltage.
Remote Sensing
The remote voltage sense compensation range is
fo r a to tal dro p o f 500 mV e qual ly sha red be twe en
the load connecting wires. It is a good practice to
shie ld the sen sin g wires to avo id oscil lation .
Each sense input must be connected to its compan-
ion output power pin when the remote sense capa-
bility is not used (s ee fig. 1).
Cas e Groundin g
The module case is isolated from the electrical
circuit of the switching regulator. It can be grounded
using the 4 corner pins.
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-R40 0 modu les is about 5°C/W. This produces
a 5 0°C temperature increase of the module surface
fo r 1 0W of int ern al power di s sip at ion .
De pe nd ing o n t he am b ien t t em pe ra ture an d/ o r on
the power dissipation, an additional heatsink or
fo r ce d ve nti lat ion m ay b e required.
Input Impedance
The module has an internal capacitor connected
between the input pins in order to assure PWM
stab ilit y. Th is capa citor ca nn ot han dle large valu es
of high frequen cy ripple curre nt and it can be pe r-
manently damaged if the primary energy source
impedance is not adequate. The use of an external
low ESR, high ripple current capacitor located as
close the module as possible is recommended.
Suitable capacitors should have a RMS current
capab ility of 2.5A RMS with a workin g volta ge of 50
VDC and an ESR of 0,1Ω at 100 kHz. When space
GS-R40 0 F AMI LY
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is a lim itation, a 2 2 µF ceram ic mu ltil ayer capacito r
must be connected to the module in put pins.
Output Vo ltag e Prog ramm ing
The GS-R4 00V and GS-R400 VB o utput vo ltage i s
programmed by using a resistor (see pin function
table and fig. 4). The resistor must be located very
close the module and the PCB layout must
mimimize injected noise. The value of the resistor
is calculated by using the following formula:
Rv = 2.67
Vo
5.1 –1
kΩ
Vo can be adjusted between 5.1 and 40V.
Current Limiting Programmi ng
The GS-R400VB current l imiting is programmed by
using a resistor (see pin functio n table and fig. 4).
The va lue of th e re sisto r is ca lcula te d by usi ng th e
following formula:
Ri = [2.2 + (5•Io)] kΩ
Module Protection
The modules are protected against occasional and
permanent short circuits of the output pi n to ground,
as well as against output current overload.
When the output current exceeds the maximum
value, th e outp ut is autom atically disabled. After a
fixed time the module starts agai n in a sof t mode.
The cycl e is repeated until the overload condition is
removed.
A crowbar output overvoltage protection is activated
whenever the output voltage exceeds the nominal
output voltage by more than 25%.
Figure 1. Load Connection
Figure 2. Remote Inhibit Operation Figure 3. Reset Operation
GS-R40 0 F AMI LY
Figure 4. Voltage and Current Programming Figure 5. Multiple Units Synchronization
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Information furnis hed is belie ved to be accurate and reliable. However, SGS-THOMSON M icroelectroni cs assume s no resp on sibility for the
consequences of use of such information nor for any infringement of patents or other rights of third partie s which may r esu lt from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specification mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Mic roel ectronics produ cts a re no t a utho rize d f or u se as crit ic al c ompo nent s in life s uppo rt de vi ces o r syst ems wi thou t e xpres s
written approval of SGS-THOMSON Microelectronics.
© 1994 SGS-THOMSON Microelectronics – All Rights Reserved
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GS-R40 0 F AMI LY
