OB2358 Current Mode PWM Power Switch IC DIP-8

OB2358 Current Mode PWM Power Switch IC DIP-8 is a highly integrated, offline PWM flyback converter designed for low-power Switch Mode Power Supply (SMPS) applications. This specialized power switch combines a dedicated current mode PWM controller with a high-voltage power MOSFET in a single DIP-8 package. Consequently, it enables designers to build extremely compact and cost-effective power adapters by minimizing the external component count. The internal circuitry provides comprehensive protection features and uses frequency shuffling technology to improve EMI performance. Furthermore, its low standby power consumption ensures compliance with modern energy-efficiency regulations. Therefore, the OB2358 remains a top choice for manufacturers producing battery chargers, power adapters, and auxiliary supplies for household appliances.

Key Features:

• Integrated Power MOSFET: The device features a rugged, high-voltage internal MOSFET, which eliminates the need for an external switching transistor.
• Frequency Shuffling: It employs proprietary frequency shuffling technology to spread the energy of switching noise, thereby reducing EMI filter costs.
• Extended Burst Mode: This feature allows the IC to operate at very low power during no-load conditions, ensuring the power supply meets global “Green Power” standards.
• Soft Start Function: An internal soft start circuit reduces stress on the transformer and secondary diode during the power-up phase.
• Comprehensive Protection: Includes built-in protection for over-current (OCP), over-temperature (OTP), under-voltage lockout (UVLO), and VDD over-voltage.

Technical Specifications:

• Drain-Source Voltage (V_DSS): 600 V
• Switching Frequency: 50 kHz (Typical)
• Output Power Range: 12 W to 27 W (Depending on input voltage and thermal design)
• Supply Voltage (V_DD): 12 V to 28 V
• Starting Current: 5 μA (Extremely low for improved efficiency)
• Operating Temperature: −20°C to +150°C (Junction)
• MOSFET R_DS(on): ≈ 4.0 Ω

Mechanical Specifications:

• Package Type: DIP-8 (Dual In-line Package)
• Encapsulation: Molded plastic epoxy
• Lead Frame: Copper-based with tin plating
• Mounting: Through-hole technology (THT)

Dimensions:

• Body Length: ≈ 9.27 mm
• Body Width: ≈ 6.35 mm
• Total Height: ≈ 4.57 mm (Including leads)
• Lead Pitch: 2.54 mm (Standard 0.1 inch)
• Row Spacing: 7.62 mm

Pinout and Wiring:

• Pin 1 (GND): Connect to the primary-side power ground.
• Pin 2 (GND): Additional ground pin for thermal dissipation and electrical reference.
• Pin 3 (FB): Feedback pin; connect to an optocoupler to regulate the output voltage.
• Pin 4 (SENSE): Current sense input; connect a resistor to set the peak current limit.
• Pin 5 (VDD): IC power supply pin; bypass this with a high-quality electrolytic capacitor.
• Pins 6, 7, 8 (DRAIN): High-voltage drain connection of the internal MOSFET; connect to the primary winding of the transformer.

Datasheet Reference:

• Download On-Bright OB2358 Power Switch Datasheet

Commonly Used in:

• AC/DC Adapters: Providing the primary power conversion for laptops, routers, and peripheral devices.
• Open Frame SMPS: Integrated into small-scale power modules for embedded industrial controls.
• Home Appliances: Powering the internal control boards of washing machines, microwaves, and air conditioners.

Applications:

• Battery Chargers: Establishing stable DC output for charging portable electronics.
• LED Driver Power: Converting mains AC into regulated DC for high-efficiency lighting systems.
• Standby Power Supplies: Efficiently managing the “always-on” circuitry in televisions and computers.

Equivalent Models:

• OB2354 / OB2353: Smaller siblings in the same family with lower power ratings, however, they share the same functional architecture.
• VIPer12A / VIPer22A: Popular alternatives from STMicroelectronics that offer similar integrated MOSFET functionality.
• CR6228: A high-performance current mode PWM controller often used as a direct cross-reference in low-cost adapter designs.

Package Includes:

• 1 x OB2358 Current Mode PWM Power Switch IC DIP-8