GS1T70-D540/2
ISDN DC-DC CONVERTER
20 January 1997
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PRELIMINARY DATA
Type
V
i
V
o
I
o
GS1T70-D540/2
28 to 115 V
out 1 : 5V
72 mA
out 2 : 40V
12 mA
FEATURES
Wide operating line termination voltage
Positive or negative input voltage polarity
Input and output filtering
Short-circuit protection on both outputs
Input power during shortcircuit within specifica-
tion
Minimum current drain during stand-by condition:
10
A for Vi<18V
Input-Output2 insulation voltage: 3000V
RMS
for
60 seconds
Output1-Output2 insulation voltage: 3000V
RMS
for 60 seconds
Mechanical dimensions (L x W x H): 50.8 mm x
50.8 mm x 18 mm (2" x 2" x 0.71")
DESCRIPTION
The GS1T70-D540/2 converter has been designed
for the "U" interface of an ISDN-NTBA (Network
Termination Basic Access) system with either 4B3T
or 2B1Q standard trasmission.
Two outputs, 5V/72mA and 40V/12mA are sup-
plied.
The converter offers short-circuit protection (short-
circuit on 40V output doesn't affect 5V output and
the input power never exceeds the limits of the
specification), input either voltage polarity, 80%
minimum efficiency at maximum load, input and
output filtering to meet very stringent noise require-
ments.
When the input voltage is below 18V, the converter
offers a very high input impedance and a maximum
quiescent current of 10
A according to the standard
ETR 080.
In addition, the wide operating input voltage range
allows it to operate within the whole range of LT
(Line Termination) battery voltage and its relevant
line resistance.
3000V
RMS
isolation voltage for 60 second is pro-
vided between input to output 2 and between output
1 and output 2. No insulation is provided between
input and output 1.
The design of the module has been conducted
using, as reference standards, the following:
EN 60950, VDE0878 part 1 class B (EMC),
EN55022 class B (EMC), CCITT 430, ETS 300 012
and ETS 300 047 (ISDN BASIC ACCESS, Safety
and Protection); anyway, please note that no certi-
fication processes have been carried out on the
module itself.
ELECTRICAL CHARACTERISTICS (T
amb
= 25
C unless otherwise specified)
Std. Conditions:
Line Termination voltage: 47 to 71V Line Resistance (Rs): 0 to 600
87 to 115V 550 to 1400
Symbol
Parameter
Test Conditions
Min
Typ
Max
Unit
Vi
Input Voltage
Std. Conditions
28
115
V
Vist
Start Up Input
Voltage
See fig. 3
28
44
V
Vo1
Output Voltage 1
Std. Conditions
4.75
5
5.25
V
Vo2
Output Voltage 2
Std. Conditions
34
40
42
V
Vor1
Output Ripple
Voltage 1
Std. Conditions
BW = 0 to 20MHz
5
20
mVpp
Vor2
Output Ripple
Voltage 2
Std. Conditions
BW = 0 to 20MHz
10
30
mVpp
Io1
Output Current 1
Std. Conditions
Po2 = 410 mW Vo1 = 5V
2
72
mA
Po2
Output Power 2
Std. Conditions
Vo1 = 4.75 to 5.25V
Vo2 = 34 to 42 V
0
420
mW
Io2max
Max Output Current 2
Std. Conditions
Io1 = 2 to 72 mA
Vo2 = 34 to 40V
12
mA
Iosc2
Output 2 Short
Circuit Current
Std. Conditions
Output Shorted (Indefinite time)
9.8
mA
Vis
Insulation Voltage
Input to Output 2
Output 1 to Output 2 (*)
f = 50 Hz
3000
VRMS
MTBF
Mean Time Before Failure
Ground Fixed
1
Mhours
Top
Operating Ambient
Temperature Range
-20
+70
C
Tstg
Storage
Temperature Range
- 40
+85
C
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20 January 1997
LT (Line Termination Voltage) = 47V to 71V
Rs (Line Resistance) = 0 to 600
LT (Line Termination Voltage) = 87V to 99V
Rs (Line Resistance) = 550 to 1400
Max
Input
Power
(mW)
NT Status
Min
Output
Power 1
(5V)[mW]
Min
Output
Power 2
(40V)[mW]
Max
Input
Power
(mW)
NT Status
Min
Output
Power 1
(5V)[mW]
Min
Output
Power 2
(40V)[mW]
450
Activated
320
0
450
Activated
320
0
950 (*)
Activated Emergency
320
410
950
Activated Emergency
320
410
90
Deactivated
40
0
90
Deactivated
40
0
180
Deactivated Emergency
40
45
180
Deactivated Emergency
40
45
1050 (*)
Activated with 40 V
Short circuit
320
Short
circuit
1050
Activated with 40V
Short circuit
320
Short
circuit
N.B.: with the following output loads:
P
o
1 (5V) : 15 mW and P
o
2 (40 V) : 410 mW , maintained for a time t > 2s, V
o
2 = 34 to 42 V
(*) Note: the values indicated are subordinated to the available input power
OUTPUT POWER CHARACTERISTICS
(*) no insulation is provided between input and output 1
GS1T70-D540/2
20 January 1997
50.8 (2.00)
21.59 (0.85)
19.05 (0.75)
18.0 (0.71)
50.8
(2.00)
1
2
3
4
5
6
5.08 (0.2)
5.08 (0.2)
10.16 (0.4)
10.16 (0.4)
7.62 (0.3)
1.27
(0.05)
Bottom view
3.0 (1.18)
O 1 (0.04)
Package V. Dimensions in mm (inches).
Figure 1. Connection diagram and mechanical data
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Pin
Description
1
Input (either polarity)
2
Input (either polarity)
3
+5V Output
4
Return for +5V Output
5
+40V Output
6
Return for +40 V Output
GALVANIC INSULATION
Galvanic insulation (3000 V for 60 s as specified in
EN60950) is provided between the input and the
output 1 (40 V output for the "S" interface).
No insulation is provided between input and output
2 (+5 V for logics put on NT1 board). See figure 2.
PIN DESCRIPTION
out 1
5V
out 2
40V
INPUT
Galvanic
insulation
barrier
3000 V
RMS
Figure 2. Galvanic insulation barrier
GS1T70-D540/2
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20 January 1997
VOLTAGE SUPPLY OPERATING AREA
Figure 3 shows the Voltage Supply Operating area
during a switching OFF-ON sequence.The start-up
voltage is 44V maximum.
One second after U-interface disconnection, and if
the input voltage remains below 18V, the maximum
quiescent input current value remains below than
10
A.
Vin
115 V
28 V
0 V
Input Voltage
Voltage Supply Operating Area
28-44 V
t >1 s
t > 1 ms
t
Input current < 10 A Area
18 V
Figure 3. Voltage Supply operating area
GS1T70-D540/2
40 V
5 V
+
-
+
-
3
4
1
2
"U"
interf.
"S"
interf.
GS5AC-40
1
2
Mains
input
40 V
+
-
Relay/Led
-
+
So
Uo
NT1 board
Relay
5
6
AC/DC converter
DC/DC converter
Led
3
4
5
6
Figure 4. Typical application example
GS1T70-D540/2
20 January 1997
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consequences of use of such information nor for any infringement of patents or other rights of third parties which may result 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 Microelectronics products are not authorized for use as critical components in life support devices or systems without express
written approval of SGS-THOMSON Microelectronics.
1997 SGS-THOMSON Microelectronics All Rights Reserved
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GS1T70-D540/2
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