The MAX256 is an integrated primary-side controller and H-bridge driver for isolated power-supply circuits. The device contains an on-board oscillator, protection circuitry and internal FET drivers to provide up to 3W of power to the primary winding of a transformer. The MAX256 can be operated using the internal program- mable oscillator or can be driven by an external clock for improved EMI performance. Regardless of the clock source being used, an internal flip-flop stage guaran- tees a fixed 50% duty cycle to prevent DC current flow in the transformer. The MAX256 operates from a single-supply voltage of +5V or +3.3V, and includes undervoltage lockout for controlled startup. The device prevents cross-conduc- tion of the H-bridge MOSFETs by implementing break- before-make switching. Thermal shutdown circuitry provides additional protection against damage due to overtemperature conditions. The MAX256 is available in the 8-pin thermally-enhanced SO package. The device is specified for the automotive (-40°C to +125°C) temperature range.
The MAX256 is an integrated primary‑side controller and H‑bridge driver designed for isolated power‑supply circuits. It operates from a single‑supply voltage of +5 V or +3.3 V and includes an on‑board programmable oscillator, undervoltage lockout, break‑before‑make switching, and thermal shutdown protection. The device is offered in an 8‑pin thermally‑enhanced SO package and is qualified for automotive temperature ranges (-40 °C to +125 °C).
Typical applications include isolated power supplies for medical equipment, industrial process control, telecommunications, and isolated RS‑485/RS‑232 data interfaces. The datasheet provides electrical characteristics, timing specifications, layout guidelines, and suggested external component manufacturers to aid designers in implementing the MAX256 in their systems.
| Supply Voltage (Vcc) Range | 3.0 V – 5.5 V |
|---|---|
| Undervoltage Lockout Threshold (typical) | 1.9 V |
| Thermal Shutdown Temperature (typical) | 165 °C |
| Maximum Output Power | Up to 3 W to the transformer |
| Package Type | 8‑pin SO‑EP |
The MAX256 operates with a supply voltage between 3.0 V and 5.5 V.