STR-A6251M Datasheet, PDF (1/7 Pages) Allegro MicroSystems – Universal-Input/15 W 67 kHz Flyback Switching Regulator

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STR-A6251M
Universal-Input/15 W
67 kHz Flyback Switching Regulator
ABSOLUTE MAXIMUM RATINGS
at T_A = +25°C
Control Supply Voltage, V_CC . . . . 36 V
Drain-Source Voltage, V_DSS . . . . . . 650 V
Drain Switching Current, I_D . . . . 2.5 A*
Peak Drain Switching Current,
I_DM . . . . . . . . . . . . . . . . . . . . . . 2.5 A
Single-Pulse Avalanche Energy,
E_AS . . . . . . . . . . . . . . . . . . . . 72 mJ
S/OCP Voltage Range,
V_OCP . . . . . . . . . . . . –0.3 V to +6 V
FB/CC/OLP Voltage Range,
V_FB/OLP . . . . . . . . . . –0.3 V to +12 V
FM Voltage Range,
V_FM . . . . . . . . . . . . . –0.3 V to +6 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 . +150°C
Internal Frame Temp., T_F . . . . +125°C
Storage Temperature Range,
T_S . . . . . . . . . . . . -40°C to +125°C
* Drain switching current is limited by tem-
perature (page 2) and safe operating area
(page 4).
The STR-A6251M is a 67 kHz PWM topology (with ±5% fre-
quency 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 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. 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 V_DSS Derating Required
■ Low r_DS(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 .
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