GS-R51212S
GS-R51515S
31W TRIPLE OUTPUT STEP-DOWN SWITCHING REGULATORS
Type
GS-R51212S
V
i
15 to 40 V
V
o
+ 5,1 V
I
o
4,5 A
0,35 A
4,5 A
0,3 A
±
12 V
+ 5,1 V
GS-R51515S
15 to 40 V
±
15 V
FEATURES
5.1V/4.5A and
±12V/0.35A
or
±15V/0.3A
output
voltages
±12
or
±15V
externally adjustable
High efficiency (81% typ.)
Short-circuit protection
Reset output
Power Fail programmable input
Inhibit/Enable control input
Soft-start
PCB or chassis mounting
DESCRIPTION
The GS-R51212S and GS-R51515S are versatile
triple output, high current step-down switching
regulators that provide +5.1V/4.5A output voltage
and an isolated
±12V/0.35A
or
±15V/0.3A
dual
output voltage.
They are ideal for microprocessor based boards
because power the logic and the communication
ports and have Reset output and Power Fail pro-
grammable input for the correct system start-up.
ABSOLUTE MAXIMUM RATINGS
Symbol
Vi
Irs
DC Input Voltage
Reset Output Sink Current
Parameter
Value
44
20
Unit
V
mA
The Inhibit/Enable pin allows the ON/OFF logic
function with TTL/CMOS compatible input signal.
The auxiliary outputs (±12V or
±15V)
are externally
adjustable in a very wide range, i.e. from
±4.25V
to
±12.45V
on GS-R51212S and from
±4.50V
to
±15.25V
(typical values) on GS-R51515S.
June 1994
1/8
GS-R51212S/GS-R51515S
ELECTRICAL CHARACTERISTICS
(T
amb
= 25°C unless otherwise specified)
Symbol
Vi
Parameter
Input Voltage
GS-R51212S
Input Voltage
GS-R51515S
Input Reflected Current
Input Reflected Current
Enable Input Voltage
Enable Input Current
Inhibit Input Voltage
Output Voltage 1
Test Conditions
Vo1 = +5.1V
Vo2 = +12V
Vo3 = – 12V
Vo1 = +5.1V
Vo2 = +15V
Vo3 = – 15V
Io1 = 4.5A
Io2 = 0.35A
Io3 = – 0.35A
Io1 = 4.5A
Io2 = 0.3A
Io3 = – 0.3A
Min
15
Typ
Max
40
Unit
V
Vi
15
40
V
lir
lir
Vien
lien
Viinh
Vo1
Vi = 24V
Io1,2,3 = Full Load
No external input capacitor
Vi = 24V
Io1,2,3 = Full Load
Ci (external) = 100µF/50V
Vi = 15 to 40V
Vi = 15 to 40V
Vi = 15 to 40V
Vi = 15 to 40V
Io1 = 0 to 4.5A
Io2 = 0 to 0.35/0.3A
Io3 = 0 to – 0.35/– 0.3A
Vi = 15 to 40V
Io1 = 0 to 4.5A
Io2 = 0 to 0.35A Io3 = 0 to – 0.35A
Vi = 15 to 40V
Io2 = 0 to 0.3A
Io1 = 0 to 4.5A
Io3 = 0 to – 0.3A
1.2
+5
0
0.5
0.15
0.8
–1
+Vi
+5.1
+5.2
App
App
V
mA
V
V
Vo2
Vo2
Vo3
Vo3
Vor1
Vor2,3
δV
OL1
δV
OL2,3
δV
OO1
δV
OO2,3
Io1
Io2
Io2
Io2
Io2
Io3
Output Voltage 2
GS-R51212S
Output Voltage 2
GS-R51515S
Output Voltage 3
GS-R51212S
Output Voltage 3
GS-R51515S
Output Ripple
Voltage 1
Output Ripple
Voltage 2,3
Line Regulation 1
Line Regulation 2,3
Load Regulation 1
Load Regulation 2,3
Output Current 1
Output Current 2*
GS-R51212S
Output Current 2*
GS-R51515S
Output Current 2*
GS-R51212S
Output Current 2*
GS-R51515S
Output Current 3*
GS-R51212S
+11.5
+14.5
– 11.5
– 14.5
+12
+15
– 12
– 15
30
50
0.5
1
2
500
+12.5
+15.5
– 12.5
– 15.5
50
100
V
V
V
V
mVpp
mVpp
mV/V
mV/V
mV/A
mV/A
Vi = 15 to 40V
Io1 = 0 to 4.5A
Io2 = 0 to 0.35A Io3 = 0 to – 0.35A
Vi = 15 to 40V
Io2 = 0 to 0.3A
Vi = 24V
Vi = 24V
Io1 = 0 to 4.5A
Io3 = 0 to – 0.3A
Io1 = 4.5A
Io2,3 = 0.35/0.3A
Vi = 15 to 40V
Io1 = 2.5A
Io2,3 = 0.35/0.3A
Vi = 15 to 40V
Io1 = 2.5A
Io2,3 = 0.35/0.3A
Vi = 24V
Io1 = 0.5 to 4.5A
Io2,3 = 0.35/0.3A
Vi = 24V
Io1 = 2.5A
Io2,Io3 = 0.05 to 0.35/0.3A
Vi = 15 to 40V
Vo1 = 5.1V
Io2,3 = 0 to 0.35/0.3A
Vi = 15 to 40V
Vo2 = +12V
Vi = 15 to 40V
Vo2 = +15V
Vi = 15 to 40V
Vo2 = +12V
Vi = 15 to 40V
Vo2 = +15V
Vi = 15 to 40V
Vo3 = – 12V
Io1 = 0 to 4.5A
Io3 = 0 to – 0.35A
Io1 = 0 to 4.5A
Io3 = 0 to – 0.3A
Io1 = 0 to 4.5A
Io3 = 0A
Io1 = 0 to 4.5A
Io3 = 0A
Io1 = 0 to 4.5A
Io2 = 0 to 0.35A
0
0
0
0
0
0
4.5
0.35
0.3
0.7
0.6
– 0.35
A
A
A
A
A
A
2/8
GS-R51212S/GS-R51515S
ELECTRICAL CHARACTERISTICS
(T
amb
= 25°C unless otherwise specified) (cont’d)
Symbol
Io3
Io3
Io3
Iosck1
Iosc1
Iosc2,3
tss
tdr
fs
Parameter
Output Current 3*
GS-R51515S
Output Current 3*
GS-R51212S
Output Current 3*
GS-R51515S
Output Current
Limit 1
Output Short-circuit
Current 1
Output Short-circuit
Current 2,3
Soft-start time
Reset Time Delay
Switching Frequency
Vi = 15 to 40V
Vo1 = 5.1V
Io1 = 0.5 to 4.5A
Vo2 = +12/+15V Vo3 = – 12/– 15V
Io2, Io3 = – 0.05 to – 0.35/– 0.3A
Vi = 24V
Io1,2,3 = Full Load
78
Test Conditions
Vi = 15 to 40V
Vo3 = – 15V
Vi = 15 to 40V
Vo3 = – 12V
Vi = 15 to 40V
Vo3 = – 15V
Vi = 15 to 40V
Vi = 15 to 40V
Vi = 15 to 40V
Io1 = 0 to 4.5A
Io2 = 0 to 0.3A
Io1 = 0 to 4.5A
Io2 = 0A
Io1 = 0 to 4.5A
Io2 = 0A
Overload
Min
0
0
0
5.5
3
0.8
10
100
100
Typ
Max
– 0.3
– 0.7
– 0.6
Unit
A
A
A
A
A
A
ms
ms
kHz
η
R th
Tcop
Tstg
Efficiency
Thermal Resistance
Operating Case
Temperature Range
Storage
Temperature Range
81
7.5
%
°C/W
+85
+105
°C
°C
0
– 40
* Note: when output current is less than 50mA, output ripple voltage increases due to discontinuous operation.
3/8
GS-R51212S/GS-R51515S
CONNECTION DIAGRAM AND MECHANICAL DATA
Package R. Dimensions in mm (inches).
PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
9
10
11
4/8
Function
GND IN
EN.
P.F.
+ Vin
RT
Vo + 5V
GND 1
Vo + 12/15V
Vo – 12/15V
ADJ.
GND Aux.
Description
Return for input voltage source. Internally connected to pin 7.
Inhibit/Enable control input. The converter is ON (ENABLE) when the voltage applied to
this pin is lower than 0.8V. The converter is OFF (INHIBIT) when this pin is unconnected or
the input voltage is in the range of 1.2 to Vi.
Power Fail programmable input. If unconnected the Power Fail threshold voltage is 11V
with 1V hysteresis (factory setting).
DC input voltage. Recommended maximum voltage is 40V.
Reset output (active high). When the supply voltage +Vin and the regulated output voltage
+Vo1 are in the correct range this signal is generated after a delay time of 100ms typical.
Regulated +5.1V output voltage.
Return for output 1 current path. Internally connected to pin 1.
Regulated +12 or +15V output.
Regulated – 12 or – 15V output.
External adjustment for output voltages
±12
and
±15V.
Return for
±12
and
±15V
output current path.
GS-R51212S/GS-R51515S
USER NOTES
Input Voltage
The recommended operating maximum DC input
voltage is 40V inclusive of the ripple voltage. The
use of an external low ESR, high ripple current
capacitor located as close the module as possible
is recommended; suggested value is 100µF/50V.
Soft-start
To avoid heavy inrush current the output voltage
rise time is typically 10ms in any condition of load.
Power Fail-Reset Circuit
The module include a voltage sensing circuit that
may be used to generate a power-on/power-off
reset signal for a microprocessor system.
The circuit sense the input supply voltage and the
output generated voltage Vo1 (+5V) and will gener-
ate the required reset signal only when both the
sensed voltages have reached the required value
for correct system operation.
When both the supply voltage and the regulated
voltage are in the correct range the output Reset
signal is generated after a delay time t
DR
of 100ms
typical.
A latch assures that if a spike is present on the
sensed voltage the delay time circuit discharges
completely before initialization of a new reset cycle.
Reset output has internal pull-up resistor of
10kOhm connected to Vo +5V pin.
Maximum sink ou tput current is 20mA at
V
RESET (sat)
= 200mV.
Fig. 1 and fig. 2 show reset waveforms.
Power Fail Programmable Input
This pin is internally connected via a divider to the
+Vin pin for Power Fail function.
The factory setting is for a value of 11V with 1V
hysteresis.
It is possible to program a different value of Power
Fail threshold by connecting a resistor (Rpf) be-
tween pin 3 (Power Fail Input) and pin 1 (GND
Input). The value of Rpf must be calculated accord-
ing to the following formula:
R
pf
=
5.1
= (kΩ)
V
pf
−
5.1
−
0.191
34
where Vpf is the desired value of Power Fail thresh-
old voltage.
Exampe: Vpf = 24V (must not be lower than 12V):
R
pf
=
5.1
=
14kΩ
24
−
5.1
−
0.191
34
Figure 1 - Reset and Power Fail waveforms.
5/8
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