ALLEGRO STR

STR-A6251M
Data Sheet
28103.43b
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Universal-Input/15 W
67 kHz Flyback Switching Regulator
ABSOLUTE MAXIMUM RATINGS
at TA = +25°C
Control Supply Voltage, VCC . . . . 36 V
Drain-Source Voltage, VDSS . . . . . . 650 V
Drain Switching Current, ID . . . . 2.5 A*
Peak Drain Switching Current,
IDM . . . . . . . . . . . . . . . . . . . . . . 2.5 A
Single-Pulse Avalanche Energy,
EAS . . . . . . . . . . . . . . . . . . . . 72 mJ
S/OCP Voltage Range,
VOCP . . . . . . . . . . . . –0.3 V to +6 V
FB/CC/OLP Voltage Range,
VFB/OLP . . . . . . . . . . –0.3 V to +12 V
FM Voltage Range,
VFM . . . . . . . . . . . . . –0.3 V to +6 V
Package Power Dissipation, PD
control (VCC × ICC(ON)) . . . . . 0.15 W
MOSFET (VDSS × ID) . . . . . . 1.35 W
total . . . . . . . . . . . . . . . . . . . . 1.5 W
MOSFET Channel Temp., TJ . +150°C
Internal Frame Temp., TF . . . . +125°C
Storage Temperature Range,
TS . . . . . . . . . . . . -40°C to +125°C
* Drain switching current is limited by temperature (page 2) and safe operating area
(page 4).
The STR-A6251M is a 67 kHz PWM topology (with ±5% frequency jittering for minimum EMI) regulator specifically designed to
satisfy the requirements for increased integration and reliability in
flyback converters. It incorporates a primary control and drive circuit
with an avalanche-rated power MOSFET. This is a higher-frequency
version of the STR-A6251.
Covering the power range from below 21 watts for a 230 VAC
input, or to 15 watts for a universal (85 to 264 VAC) input, this device
can be used in a wide range of applications, from DVD players and
VCR player/recorders to ac adapters for cellular phones and digital
cameras. An auto-burst standby function reduces power consumption at
light load, while multiple protections, including the avalanche-energy
guaranteed MOSFET, provide high reliability of system design.
Cycle-by-cycle current limiting, undervoltage lockout with hysteresis, 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. It is provided in an 8-pin mini-DIP
plastic package with pin 6 removed.
FEATURES AND BENEFITS
■ 67 kHz PWM with ±5% Frequency Jittering
Cost Reduction of EMI Noise Filtering
■ Rugged 650 V Avalanche-Rated MOSFET
Simplified Surge Absorption
No VDSS Derating Required
■ Low rDS(on) (3.95 Ω maximum)
■ Auto-Burst Mode for Stand-By Operation or Light Loads
Less Transformer Audible Noise
■ Built-In Leading Edge Blanking
■ Soft Start and Low Start-Up Current
Start-Up Circuit Disabled in Operation
■ Low Operating Current (4 mA max)
■ Automatic Burst Stand-By (intermittent operation)
Input Power <0.1 W at No Load
continued
Always order by complete part number, e.g., STR-A6251M .
Sanken Power Devices
from Allegro MicroSystems
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STR-A6251M
Universal-Input/15 W
67 kHz Flyback Switching Regulator
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/Constant Current
■ Multiple Protections:
Pulse-by-Pulse Overcurrent Protection (OCP)
Overload Protection (OLP) with Auto Restart
Latching Overvoltage Protection (OVP)
Undervoltage Lockout (UVLO) with Hysteresis
Latching Thermal Shutdown (TSD)
■ Molded Small-Size 8-Pin Package
For Low-Height SMPS
This data sheet is based on Sanken data sheet SSE-23420.
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Copyright © 2005 Allegro MicroSystems, Inc.
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STR-A6251M
Universal-Input/13 W
67 kHz Flyback Switching Regulator
ELECTRICAL CHARACTERISTICS at TA = 25°C, VCC = 18 V (unless otherwise specified).
Pin
No.
8-1
Symbol
V(BR)DSS
8
I DSS
On-State Resistance
MOSFET Switching Time
Operation-Start Voltage
8-1
8-3
5-3
rDS(on)
Operation-Stop Voltage
Maximum Switching Frequency
Frequency-Jitter Deviation
Maximum ON Duty Cycle
Circuit Current in Operation
Circuit Current in Non-Operation
FM Voltage
5
8
8
8
Characteristic
Drain-to-Source Breakdown Volt.
Drain Leakage Current
-3
-3
-3
-3
5
5
2-3
FM Current
OCP Threshold Voltage
Leading Edge Blanking Time
Burst Threshold Voltage
OLP Threshold Voltage
Current at OLP Operation
OLP Delay Time
Maximum FB Current
CC Set Voltage
CC Reset Voltage
Start-Up Current
OVP Operation Voltage
OVP/TSD Latch Sustaining Current
OVP/TSD Latch Release Voltage
Thermal Shutdown
Thermal Resistance
2
1
8
4
4
-3
-3
-3
-3
4
4-3
4
4-3
4-3
5
5-3
5
5-3
-
tf
VCC(ON)
VCC(OFF)
fosc(max)
Δf osc
D max
I CC(ON)
ICC(OFF)
VFMH
VFML
IFMH
IFML
VOCP
t bw
Vburst
VOLP
IOLP
tOLP
IFB(MAX)
VSET(CC)
VRES(CC)
I startup
VCC(OVP)
I CC(H)
VCC
TJ
R θJF
Test Conditions
ID = 300 µA,
V1 – V3 = 0 V (short)
VDS = 650 V,
V1 – V3 = 0 V (short)
ID = 0.4 A
VCC = 0 t 15.7 V
VCC = 15.7 t 9 V
VCC = 12 V
fosc = fosc(max)
fosc < fosc(max)
VCC
VCC
VCC
VCC
VCC
-
= 25 V
= 13 V
= 18 t 35.2 V
=35.2 t 8.6 V
=35.2 t 5.9 V
Ratings
Min
Typ
Max
650
-
Units
V
-
-
300
µA
12.9
14.3
3.95
250
15.7
Ω
ns
V
9.0
60
4.0
70
4.0
3.2
-7.7
7.7
0.67
240
1.00
7.3
-12
0.84
220
4.9
3.5
0.84
28.8
5.9
125
-
10
67
6.7
76
14
4.5
3.6
-11.0
11.0
0.74
350
1.12
8.6
-18
1.20
310
5.8
3.9
1.20
32.0
7.2
140
-
11
V
74
kHz
9.4
kHz
82
%
4.0
mA
25
µA
5.0
V
4.0
V
-15.4
µA
15.4
µA
0.81
V
460
ns
1.24
V
9.9
V
-25
µA
1.56
s
430
µA
6.7
V
4.3
V
1.56
mA
35.2
V
270
µA
8.6
V
°C
52 °C/W
Typical values are given for circuit design information only.
Negative current is defined as coming out of (sourcing) the specified terminal.
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STR-A6251M
Universal-Input/15 W
67 kHz Flyback Switching Regulator
MOSFET TYPICAL CHARACTERISTICS
Recommended Operating Conditions
Operating Ambient Temperature ....... -20°C to +100°C
Operating Junction Temperature ....... -20°C to +125°C
Maximum Frame Temperature ........................ +115°C
For the availability of parts meeting -40°C requirements, contact
Allegro’s Sales Representative.
Avalanche energy is measured at VDD = 99 V,
L = 20 mH, IL = 2.5 A.
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
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STR-A6251M
Universal-Input/13 W
67 kHz Flyback Switching Regulator
MOSFET TYPICAL CHARACTERISTICS (cont’d)
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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STR-A6251M
Universal-Input/15 W
67 kHz Flyback Switching Regulator
APPLICATIONS INFORMATION
Typical Application
NOTE: The start-up performance of the IC can only be
guaranteed for values of C2 greater than 22 µF. This value
is required to keep the internal supply voltage within
regulation during IC initialization.
Complete product description and applications information
is provided in Application Note 28103.40, Series STRA6200 Flyback Switching Regulators.
The products described herein are manufactured in Japan by Sanken
Electric Co., Ltd. for sale by Allegro MicroSystems, Inc.
Sanken products listed in this publication are designed and intended
for use as components in general-purpose electronic equipment or
apparatus (home appliances, office equipment, telecommunication
equipment, measuring equipment, etc.). Their use in any application
requiring radiation hardness assurance (e.g., aerospace equipment) is
not supported.
Sanken and Allegro reserve the right to make, from time to time, such
departures from the detail specifications as may be required to permit
improvements in the performance, reliability, or manufacturability of its
products. Therefore, the user is cautioned to verify that the information
in this publication is current before placing any order.
When using the products described herein, the applicability and
suitability of such products for the intended purpose shall be reviewed at
the users responsibility.
Although Sanken undertakes to enhance the quality and reliability of
its products, the occurrence of failure and defect of semiconductor
products at a certain rate is inevitable.
Users of Sanken products are requested to take, at their own risk,
preventative measures including safety design of the equipment or
systems against any possible injury, death, fires or damages to society
due to device failure or malfunction.
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When considering the use of Sanken products in applications where
higher reliability is required (transportation equipment and its control
systems or equipment, fire- or burglar-alarm systems, various safety
devices, etc.), contact a company sales representative to discuss and
obtain written confirmation of your specifications.
The use of Sanken products without the written consent of Sanken in
applications where extremely high reliability is required (aerospace
equipment, nuclear power-control stations, life-support systems, etc.) is
strictly prohibited.
The information included herein is believed to be accurate and
reliable. Application and operation examples described in this publication are given for reference only and Sanken and Allegro assume no
responsibility for any infringement of industrial property rights,
intellectual property rights, or any other rights of Sanken or Allegro or
any third party that may result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
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STR-A6251M
Universal-Input/13 W
67 kHz Flyback Switching Regulator
PACKAGE DIMENSIONS
Dimensions in Inches
(for reference only)
Dimensions in Millimeters
(controlling dimensions)
Terminal Finish: Pure Sn, 2nd level interconnect category (e3).
Product Weight: Approx. 0.51 g.
Frame temperature, TF, is measured at the root of pin 3.
For more efficient heat radiation, connect a broad PCB pattern
at pins 7 and 8.
EI 26EI
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