IR3637SPBF is a synchronous buck regulator designed by IR company for low voltage applications. It uses an 8-pin SOIC package and has a built-in 0.8V reference voltage for precise output voltage regulation. The device has dual input undervoltage lockout, external programmable soft-start function, and output undervoltage detection function, which will latch off the device when an output short is detected.
The IR3637SPBF is a 1 % accurate synchronous PWM controller designed for on‑board DC‑to‑DC buck regulator applications. It operates from a single 5 V supply, uses an internal 400 kHz oscillator, and includes a programmable soft‑start function.
Key features include a 0.8 V reference voltage, short‑circuit protection, under‑voltage lockout, and a fixed‑frequency voltage‑mode control loop. Typical applications are computer peripheral voltage regulation, memory power supplies, graphics cards, and low‑cost on‑board DC‑DC converters.
| Reference Voltage | 0.8 V |
|---|---|
| Operating Frequency | 400 kHz |
| Supply Voltage Range | 5 V (single supply) |
| Soft‑Start Function | Programmable via SS pin |
| Static Supply Current (Vcc) | 1 mA (typical) |
| UVLO Threshold (Vcc) | 4.0 V – 4.4 V |
The controller uses a fixed internal oscillator that runs at 400 kHz.
Output voltage is set by an external resistor divider that provides 0.8 V at the Fb pin when the desired output is reached.
The SS pin (pin 8) is the soft‑start pin; connecting an external capacitor to ground sets the start‑up time.