Universal-Input/58 W Off-Line Quasi-
Resonant Flyback Switching Regulator
Data Sheet
28103.31*
STR-W6753
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 . . . . . .
650 V
Drain Switching Current, I
D
. . . 11.2 A*
Peak Drain Switching Current,
I
DM
. . . . . . . . . . . . . . . . . . . . . 11.2 A
Single-Pulse Avalanche Energy,
E
AS
. . . . . . . . . . . . . . . . . . . 145 mJ
OCP/BD Voltage Range,
V
OCP
. . . . . . . . . . . . 1.5 V to +5 V
FB Input Current, I
FB
. . . . . . . . 10 mA
FB Voltage Range, V
FP
0.5 V to +9 V
Package Power Dissipation, P
D
control (V
CC
I
CC(ON)
) . . . . . . 0.8 W
MOSFET (V
DSS
I
D
) . . . See Graph
MOSFET Channel Temp., T
J
. +150C
Internal Frame Temp., T
F
. . . . +115C
Operating Temperature Range,
T
A
. . . . . . . . . . . -20C to +115C
Storage Temperature Range,
T
S
. . . . . . . . . . . . -40C to +125C
* Drain switching current is limited by tem-
perature (page 2) and safe operating area
(page 5).
For the availability of parts meeting -40C
requirements, contact Allegro's Sales Represen-
tative.
The STR-W6753 is a quasi-resonant regulator specifically designed
to satisfy the requirements for increased integration and reliability in
switch-mode power supplies. It incorporates a primary control and drive
circuit with an avalanche-rated power MOSFET. The regulator exhibits
only low-level high-frequency EMI noise because of soft switching of
the MOSFET close to ground (bottom point). A bottom-skip function
minimizes an increase of operational frequency during light loads to
improve system efficiency over the entire load range.
Covering the power range from below 120 watts for a 230 VAC
input, or 58 watts for a universal input (85 to 264 VAC), this device 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, which is internally triggered by sensing on time, reduces
power consumption at light load. An externally triggered standby mode
reduces the input power further. Multiple protections, including the
avalanche-energy-guaranteed MOSFET, provide high reliability of
system design. Devices with an increased output power rating are the
STR-W6754 and STR-W6756.
Cycle-by-cycle current limiting, undervoltage lockout with hyster-
esis, and overvoltage protection protect the power supply during the
normal overload and fault conditions. Overvoltage protection is 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. The
STR-W6753 is provided in a fully molded TO-220-style flange-
mounted, high power, isolated plastic package.
FEATURES
AND
BENEFITS
Rugged 650 V Avalanche-Rated MOSFET
Simplified Surge Absorption
No V
DSS
Derating Required
1.7
Maximum
r
DS(on)
Two Operational Modes by Automatic Switching:
Quasi-Resonant Mode for Normal Operation
Burst Mode for Standby Operation or Light Loads
Automatic or Manually Triggered Burst Standby
Input Power <0.1 W at No Load
Low Operating Current (6 mA typ)
-- continued
Always order by complete part number, e.g., STR-W6753 .
STR-W6753
Universal-Input/58 W Off-Line Quasi-
Resonant Flyback Switching Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
2
Switching
Regulators
Copyright 2005 Allegro MicroSystems, Inc.
FUNCTIONAL BLOCK DIAGRAM
FEATURES
AND
BENEFITS (cont'd)
Auto-Bias Function
Stable Burst Operation Without Generating Interference
Internal Off-Timer Circuit
Built-In Constant-Voltage Drive
Multiple Protections:
Pulse-by-Pulse Overcurrent Protection
Overload Protection with Auto Recovery
Latching Overvoltage Protection
Undervoltage Lockout with Hysteresis
RoHS Compliant
STR-W6753
Universal-Input/58 W Off-Line Quasi-
Resonant Flyback Switching Regulator
www.allegromicro.com
3
Switching
Regulators
ELECTRICAL CHARACTERISTICS at T
A
= +25C, V
CC
= 20 V, voltage measurements are referenced to S/GND terminal
(unless otherwise specified).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Start-Up Operation
Operation Start Voltage
V
CC(ON)
Turn-on, V
CC
= 0
19.9 V
16.3
18.2
19.9
V
Soft-Start Operation Stop Voltage
V
SS/OLP
1.1
1.2
1.4
V
Soft-Start Oper. Charging Current
I
SS/OLP
-390
-550
-710
A
Operation Stop Voltage
V
CC(OFF)
Turn-off, V
CC
= 19.9
8.8 V
8.8
9.7
10.6
V
Circuit Current in Non-Operation
I
CC(OFF)
V
CC
= 15 V
100
A
Normal Operation
Drain-Source Breakdown Voltage
V
(BR)DSS
I
D
= 300 A
650
V
Drain Leakage Current
I
DSS
V
DS
= 650 V
300
A
On-State Resistance
r
DS(on)
I
D
= 1.4 A, T
J
= +25C
1.7
Switching Time
t
f
400
ns
Circuit Current
I
CC(ON)
6.0
mA
Oscillation Frequency
f
osc
19
22
25
kHz
Bottom-Skip Oper. Threshold Volt.
V
OCPBD(BS1)
-605
-665
-720
mV
V
OCPBD(BS2)
-385
-435
-485
mV
Quasi-Resonant Oper. Threshold
V
OCPBD(TH1)
280
400
520
mV
V
OCPBD(TH2)
670
800
930
mV
Feedback-Pin Threshold Voltage
V
FB(OFF)
1.32
1.45
1.58
V
Feedback-Pin Current
I
FB(ON)
600
1000
1400
A
Standby Operation
Standby Operation Start Voltage
V
CC(S)
V
CC
= 0
12.2 V
10.3
11.1
12.1
V
Standby Oper. Start Volt. Interval
V
CC
1.10
1.35
1.65
V
Standby Non-Operation Current
I
CC(S)
V
CC
= 10.2 V
20
56
A
Feedback-Pin Current
I
FB(ON)
V
CC
= 10.2 V
4.0
14
A
Feedback-Pin Threshold Voltage
V
FB(S)
V
CC
= 12.2 V
0.55
1.10
1.50
V
Minimum ON Time
t
on(min)
0.5
0.8
1.2
s
continued next page ...
STR-W6753
Universal-Input/58 W Off-Line Quasi-
Resonant Flyback Switching Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
4
Switching
Regulators
Protection Operation
OVP Operation Voltage
V
CC(OVP)
Turn-off, V
CC
= 0
29.9 V
25.5
27.7
29.9
V
Maximum ON Time
t
on(max)
27.5
32.5
39.0
s
OLP Operation Voltage
V
SSOLP
4.0
4.9
5.8
V
OLP Operation Current
I
SSOLP
-6.0
-11
-16
A
Overcurrent Detect. Threshold Volt.
V
OCPBD(LIM)
-0.895 -0.940 -0.995
V
OCP/BD-Pin Current
I
OCPBD
-40
-100
-250
A
Latch Holding Current
I
CC(H)
V
CC
= 29.9
V
CC(OFF)
0.3 V
45
140
mA
Latch Release Voltage
V
CC(L)
V
CC
= 29.9
6 V
6.0
7.2
8.5
V
Other
Thermal Resistance
R
JF
Output junction-to-frame
2.0
C/W
NOTES: 1. Typical Data is for design information only.
2. Negative current is defined as coming out of (sourcing) the specified device termninal.
ELECTRICAL CHARACTERISTICS at T
A
= +25C, V
CC
= 20 V, voltage measurements are referenced to S/GND terminal
(unless otherwise specified).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
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