MAX845

19-0372; Rev 4; 10/97 KIT ATION EVALU E L B A AVAIL Isolated Transformer Driver for PCMCIA Applications ____________________________Features o Transformer Driver for Ultra-Thin 5V-µs Transformers o Isolated DC-to-DC Power Supply for PCMCIA Applications o 450kHz Minimum Switching Frequency o Ultra-Low Input Supply Current Ripple o Single +5V or +3.3V Supply o 5µW Low-Power Shutdown Mode o 8-Pin SO and µMAX Packages o Low Output Ripple Permits Miniature Output Capacitors _______________General Description The MAX845 provides an isolated power supply small enough to fit in thin PCMCIA cards and space-sensitive applications. It drives a low-profile center-tapped transformer primary from a 5V or 3.3V DC power supply. The secondary can be wound to provide any isolated positive or negative voltage at powers up to 750mW. The MAX845 consists of an oscillator followed by a toggle flip-flop. The flip-flop generates two 50% duty-cycle square waves, which are complementary at half the oscillator frequency (450kHz, min). These two signals drive the ground-referenced N-channel power switches. Internal circuitry ensures break-before-make action between the two switches. A low-power shutdown disables both the switches and the oscillator, reducing power consumption. An evaluation kit (MAX845EVKIT-MM) is available to evaluate lowprofile 5V 40mA and 5V 100mA applications. MAX845 ________________________Applications PCMCIA Modem Cards Isolated Data Acquisition Isolated Interface Power Supply...