NTE7125 & NTE7126
Integrated Circuit
Switching Regulator
Description:
The NTE7125 and NTE7126 are integrated circuits in a 12–Lead SIP type package incorporating all
the power switching, amplifier, error detection, and overcurrent protection circuits required in a self–
extcitation type semi–regulated off–line switching regulator. As a result, these devices can be used
in the design of switching power supplies with a minimal number of external components. Further-
more, the adoption of MOSFET power switching elements supports a higher oscillation frequency
than possible with bi–polar transistors. This allows smaller pulse transformers and capacitors to be
used, making it possible to construct miniature power supply systems.
Features:
D
Power MOSFET Devices
D
Ideal for Semi–Regulated Control Switching Supplies
D
Error Detection Circuit On–Chip (40.5V
±0.5V
Set Refernce Voltage)
D
Overcurrent Protection Circuit On–Chip
D
Higher Oscillation Frequency allows the use of Smaller Pulse Transformers
D
IMST Substrate acts as an Electromagnetic Shield, makinf Low–Noise Designs Possible
Applications:
D
CRT/CTV Power Supplies
D
Office Automation Equipment Power Supplies
Absolute Maximum Ratings:
(T
A
= +25°C unless otherwise specified)
Operating Substrate Temperature (Recommended value is +105°C), T
C
max . . . . . . . . . . . . +115°C
AC Input Voltage, V
AC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140V
rms
OPerating Temperature Range, T
opr
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –10° to +85°C
Storage Temperature Range, T
stg
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –30° to +115°C
Maximum Output Power (V
O
= 135V), W
O
max
NTE7125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110W
NTE7126 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145W
TR1
Drain Current, I
D
NTE7125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6A
NTE7126 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8A
Pulse Drain Current, I
D (pulse)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20A
Drain Reverse Current, I
DR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6A
Gate–Source Voltage, V
GSS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±30V
Absolute Maximum Ratings (Cont’d):
(T
A
= +25°C unless otherwise specified)
TR1 (Cont’d)
Allowable Power Dissipation, P
D
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78.1W
Chip Junction Temperature, T
J
max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C
Thermal Resistance, Junction–to–Case, R
thJ–C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6°C/W
ZD1
Allowable Power Dissipation, P
ZD1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500mW
Chip Junction Temperature, T
J (ZD1)
max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +125°C
Thermal Resistance, Junction–to–Case, R
thJ–C (ZD1)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2°C/W
Allowable Operating Ranges:
(T
A
= +25°C unless otherwise specified)
Pin4 Input Voltage, V
4
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±6
to
±24V
Oscillator Frequency, f
OSC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 to 120kHz
Operating Characteristics:
(T
A
= +25°C, T
C
= +25°C unless otherwise specified)
Parameter
Output Voltage Setting
Output Voltage Temperature Coefficient
TR1
Drain–Source Breakdown Voltage
Gate–Source Cutoff Voltage
ON Resistance
NTE7125
NTE7126
Input Capacitance
ZD1
Zener Voltage
V
Z
I
Z
= 5mA
23.7
–
26.3
V
V
(BR)DSS
I
D
= 10mA, V
GS
= 0V
V
GS(off)
R
DS(on)
I
D
= 1mA, V
DS
= 10V
I
D
= 2.5A, V
GS
= 10V
500
2.0
–
–
–
–
–
1.4
0.8
800
–
3.0
1.8
1.8
–
V
V
Ω
Ω
pF
Symbol
Test Conditions
I
IN
= 8mA
T
C
= 0° to +105°C, I
IN
= 8mA
Min
40.0
–
Typ
40.5
7
Max
41.0
–
Unit
V
mV/°
C
C
iss
V
DS
= 10V, V
GS
= 0V, f = 1MHz
Pin Connection Diagram
(Front View)
12
TR1 Drain
11
TR1 Drain
10
9
8
7
6
5
4
3
2
1
No Pin
TR1 Source
TR1 Source
OCP Setting Level Input
Amplifier Circuit Control
TR1 Gate
Drive Voltage Input
GND
Error Detection Level
V
ref
(40.5V typ) Input
1.835 (46.6)
1.622 (41.2)
.335 (8.5)
1.004
(25.5)
.500
(12.7)
1
12
.787
(20.0)
.100 (2.54)
1.100 (27.9)
.261 (6.63)
.157
(4.0)
