120 V/12 or 16 W
Flyback Switching Regulators
Data Sheet
28103.21*
STR-A6131
AND
STR-A6132
Sanken Power Devices
from Allegro MicroSystems
Switching
Regulators
ABSOLUTE MAXIMUM RATINGS
at T
A
= +25C
Control Supply Voltage, V
CC
. . . . 35 V
Drain-Source Voltage, V
DSS . . . . . .
500 V
Drain Switching Current, I
D
STR-A6131 . . . . . . . . . . . . . . 3.2 A*
STR-A6132 . . . . . . . . . . . . . . 4.0 A*
Peak Drain Switching Current, I
DM
STR-A6131 . . . . . . . . . . . . . . . 3.2 A
STR-A6132 . . . . . . . . . . . . . . . 4.0 A
Single-Pulse Avalanche Energy, E
AS
STR-A6131 . . . . . . . . . . . . . . 32 mJ
STR-A6132 . . . . . . . . . . . . . . 78 mJ
Start-Up-Pin Voltage Range,
V
startup
. . . . . . . . . 0.3 V to +600 V
OCP Voltage Range,
V
OCP
. . . . . . . . . . . . 0.5 V to +6 V
FB/OLP Voltage Range,
V
FB/OLP
. . . . . . . . . . 0.5 V to +10 V
Package Power Dissipation, P
D
control (V
CC
I
CC(ON)
) . . . . . 0.15 W
MOSFET (V
DSS
I
D
) . . . . . . 1.35 W
total . . . . . . . . . . . . . . . . . . . . 1.5 W
MOSFET Channel Temp., T
J
. +150C
Internal Frame Temp., T
F
. . . . +125C
Operating Temperature Range,
T
A
. . . . . . . . . . . -20C to +125C
Storage Temperature Range,
T
S
. . . . . . . . . . . . -40C to +125C
* Drain switching current is limited by tem-
perature (page 2) and safe operating area
(page 4).
For the availability of parts meeting -40C
requirements, contact Allegro's Sales Represen-
tative.
The STR-A6131 and STR-A6132 are PRC topology (fixed off-time)
regulators specifically designed to satisfy the requirements for increased
integration and reliability in flyback converters. They incorporate a
primary control and drive circuit with avalanche-rated power
MOSFETs. The STR-A6132 features higher switching current and
avalanche-energy ratings and lower on-resistance.
Covering the power range from below 12 watts to 16 watts for a 120
VAC input, these devices can be used in a range of applications, from
DVD and VCR players to ac adapters for cellular phones and digital
cameras. An auto-standby function reduces power consumption at light
load, while multiple protections, including the avalanche energy guaran-
teed MOSFET, provide high reliability of system design.
Cycle-by-cycle current limiting, undervoltage lockout with hyster-
esis, overvoltage protection, and thermal shutdown protect the power
supply during the normal overload and fault conditions. Overvoltage
protection and thermal shutdown are latched after a short delay. The
latch may be reset by cycling the input supply. Low start-up current and
a low-power standby mode selected from the secondary circuit completes
a comprehensive suite of features. Both devices are provided in an 8-pin
mini-DIP plastic package.
FEATURES
AND
BENEFITS
Rugged 500 V Avalanche-Rated MOSFET
Simplified Surge Absorption
No V
DSS
Derating Required
Choice of
r
DS(on)
(2.62
or 3.95
maximum)
Two Operational Modes by Automatic Switching:
PRC Mode for Normal Operation
Burst Mode for Stand-By Operation or Light Loads
Built-In Leading Edge Blanking
Low Start-Up Current
Start-Up Circuit Disabled in Operation
Low Operating Current (1.5 mA typ)
Automatic Burst Stand-By (intermittent operation)
Input Power <0.1 W at No Load
-- continued
Always order by complete part number, e.g., STR-A6131 .
STR-A6131 and STR-A6132
120 V/12 or 16 W
Flyback Switching Regulators
www.allegromicro.com
3
Switching
Regulators
ELECTRICAL CHARACTERISTICS
at T
A
= 25C, V
CC
= 20 V (unless otherwise specified).
Pin
Ratings
Characteristic
No.
Symbol
Test Conditions
Min
Typ
Max
Units
Drain-to-Source Breakdown Volt.
8 - 1
V
(BR)DSS
I
D
= 300 A,
500
-
-
V
V
1
V
3
= 0 V (short)
Drain Leakage Current
8 - 1
I
DSS
V
DS
= 500 V,
-
-
300
A
V
1
V
3
= 0 V (short)
On-State Resistance
8 - 1
r
DS(on)
STR-A6131, I
D
= 0.4 A
-
-
3.95
STR-A6132, I
D
= 0.4 A
-
-
2.62
MOSFET Switching Time
8 - 3
t
f
-
-
-
250
ns
Operation Start Voltage
2 - 3
V
CC(ON)
V
CC
= 0
19.2 V
16
17.5
19.2
V
Operation Stop Voltage
2 - 3
V
CC(OFF)
V
CC
= 19.2
9 V
9.0
10
11
V
Circuit Current in Operation
2 - 3
I
CC(ON)
-
-
-
4.0
mA
Circuit Current in Non-Operation
2 - 3
I
CC(OFF)
V
CC
= 14 V
-
-
50
A
Auto-Bias Threshold Voltage
2 - 3
V
CC(bias)
V
CC
= 20
9.6 V
9.6
10.6
11.6
V
V
CC(bias)
- V
CC(OFF)
-
-
-
0.2
0.6
-
V
Maximum OFF Time
8 - 3
t
OFF
-
7.3
8.0
8.7
s
OCP Threshold Voltage
1 - 3
V
OCP
-
0.69
0.77
0.86
V
Leading Edge Blanking Time
8 - 3
t
b
-
200
320
480
ns
Burst Threshold Voltage
4 - 3
V
burst
0.70
0.79
0.88
V
OLP Threshold Voltage
4 - 3
V
OLP
-
6.5
7.2
7.9
V
Current at OLP Operation
4 - 3
I
OLP
-
-18
-26
-35
A
Maximum FB Current
4 - 3
I
FB(MAX)
-
227
300
388
A
Start-Up Current
5 - 3
I
startup
V
CC
= 15 V
340
790
1230
A
Start-Up Circuit Leakage Current
5 - 3
I
start(leak)
-
-
-
30
A
OVP Operation Voltage
2 - 3
V
CC(OVP)
V
CC
= 0
34.1 V
28.7
31.2
34.1
V
OVP/TSD Latch Sustaining Current
2 - 3
I
CC(H)
V
CC
=34.1
8.5 V
-
-
200
A
OVP/TSD Latch Release Voltage
2 - 3
V
CC
V
CC
=34.1
6.6 V
6.6
7.3
8.0
V
Thermal Shutdown
-
T
J
-
135
-
-
C
Thermal Resistance
-
R
JF
-
-
-
52
C/W
WARNING -- These devices are designed to be operated at lethal voltages and energy levels. Circuit designs
that embody these components must conform with applicable safety requirements. Precautions must
be taken to prevent accidental contact with power-line potentials. Do not connect grounded test
equipment.
The use of an isolation transformer is recommended during circuit development and breadboarding.
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