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STR-A6251 AND STR-A6252
Universal-Input/15 W 50 kHz Flyback Switching Regulators
The STR-A6251 and STR-A6252 are 50 kHz PWM topology (with 5% frequency jittering for minimum EMI) 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-A6252 features higher allowable switching current and lower on-resistance. The STR-A6251 is also available for 67 kHz operation. Covering the power range from below 21 watts or 24 watts for a 230 VAC input, or to 15 or 20 watts for a universal (85 to 264 VAC) input, these devices 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. Both devices are provided in an 8-pin mini-DIP plastic package with pin 6 removed. FEATURES AND BENEFITS 50 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 Choice of rDS(on) (2.8 or 3.95 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) continued Always order by complete part number, e.g., STR-A6251 .
Data Sheet 28103.42b
ABSOLUTE MAXIMUM RATINGS at TA = +25C
Control Supply Voltage, VCC . . . . 36 V Drain-Source Voltage, VDSS . . . . . . 650 V Drain Switching Current, ID STR-A6251 . . . . . . . . . . . . . . 2.5 A* STR-A6252 . . . . . . . . . . . . . . 3.0 A* Peak Drain Switching Current, IDM STR-A6251 . . . . . . . . . . . . . . . 2.5 A STR-A6252 . . . . . . . . . . . . . . . 3.0 A Single-Pulse Avalanche Energy, EAS STR-A6251 . . . . . . . . . . . . . . 72 mJ STR-A6252 . . . . . . . . . . . . . 123 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 x ICC(ON)) . . . . . 0.15 W MOSFET (VDSS x ID) . . . . . . 1.35 W total . . . . . . . . . . . . . . . . . . . . 1.5 W MOSFET Channel Temp., TJ . +150C Internal Frame Temp., TF . . . . +125C Storage Temperature Range, TS . . . . . . . . . . . . -40C to +125C
* Drain switching current is limited by temperature (page 2) and safe operating area (page 4).
Sanken Power Devices from Allegro MicroSystems
STR-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
FUNCTIONAL BLOCK DIAGRAM
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FEATURES
AND
BENEFITS (cont'd)
Automatic Burst Stand-By (intermittent operation) Input Power <0.1 W at No Load 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-23297 and SSE-23298.
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 Copyright (c) 2005 Allegro MicroSystems, Inc.
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Pin No. 8-1 8 8-1 8-3 5 5 8 8 8 -3 -3 -3 -3 -3 5 5 2-3 2 -3 -3 -3 -3 4 4-3 4 4-3 4-3 5 5-3 5 5-3 1 8 4 4
STR-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
ELECTRICAL CHARACTERISTICS at TA = 25C, VCC = 18 V (unless otherwise specified).
Characteristic Drain-to-Source Breakdown Volt. Drain Leakage Current On-State Resistance MOSFET Switching Time Operation-Start Voltage Operation-Stop Voltage Maximum Switching Frequency Frequency-Jitter Deviation Maximum ON Duty Cycle Circuit Current in Operation Circuit Current in Non-Operation FM Voltage 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 Symbol V(BR)DSS I DSS Test Conditions ID = 300 A, V1 - V3 = 0 V (short) VDS = 650 V, V1 - V3 = 0 V (short) STR-A6251, ID = 0.4 A STR-A6252, ID = 0.4 A VCC = 0 15.7 V VCC = 15.7 9 V VCC = 12 V fosc = fosc(max) fosc < fosc(max) Ratings Min Typ Max 650 12.9 9.0 45 3.0 70 4.0 3.2 -7.7 7.7 0.67 220 1.00 7.3 -12 0.84 220 4.9 3.5 0.77 28.8 5.9 125 14.3 10 50 5.0 76 14 4.5 3.6 -11.0 11.0 0.74 320 1.12 8.6 -17 1.20 310 5.8 3.9 1.10 32.0 7.2 140 300 3.95 2.8 250 Units V A ns
rDS(on)
tf VCC(ON) VCC(OFF) fosc(max) f 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 JF
VCC VCC VCC VCC VCC -
= 25 V = 13 V = 18 35.2 V =35.2 8.6 V =35.2 5.9 V
15.7 V 11 V 55 kHz 7.0 kHz 82 % 4.0 mA 25 A 5.0 V 4.0 V -14.3 A 14.3 A 0.81 V 420 ns 1.24 V 9.9 V -22 A 1.56 s 400 A 6.7 V 4.3 V 1.43 mA 35.2 V 270 A 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-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
MOSFET TYPICAL CHARACTERISTICS STR-A6251 STR-A6252
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Avalanche energy is measured at VDD = 99 V, L = 20 mH, IL = 2.5 A.
Avalanche energy is measured at VDD = 99 V, L = 20 mH, IL = 3.0 A.
Recommended Operating Conditions Operating Ambient Temperature ....... -20C to +100C Operating Junction Temperature ....... -20C to +125C Maximum Frame Temperature ........................ +115C
For the availability of parts meeting -40C requirements, contact Allegro's Sales Representative.
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036
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STR-A6251
STR-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
MOSFET TYPICAL CHARACTERISTICS (cont'd)
STR-A6252
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-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
APPLICATIONS INFORMATION
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Typical Application NOTE: The start-up performance of the IC can only be guaranteed for values of C2 greater than 22 F. 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 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.
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. 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.
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036
ing rs h itc lato Sw egu R
STR-A6251 and STR-A6252 Universal-Input/15 W 50 kHz Flyback Switching Regulators
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 www.allegromicro.com
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