MAXIM MAX4820/4821 说明书
The MAX4820/MAX4821 8-channel relay drivers offer built-in kickback protection and drive +3.3V/+5V non- latching or dual-coil-latching relays. These devices are especially useful when driving +3V relays. Each inde- pendent open-drain output features a 2Ω on-resistance and is guaranteed to sink 70mA (min) of load current. Both devices consume less than 50µA (max) quiescent current and have 1µA output off-leakage current. The MAX4820 features an SPI™-/QSPI™-/MICROWIRE™- compatible serial interface. Input data is shifted into an 8- bit shift register and latched to the outputs when CS transitions from low to high. Each data bit in the shift reg- ister corresponds to a specific output, allowing indepen- dent control of all outputs. The MAX4821 features a 4-bit (A0, A1, A2, LVL) paral- lel-input interface. The first three bits (A0, A1, A2) deter- mine the output address, and the fourth bit (LVL) determines whether the selected output is switched on or off. Data is latched to the outputs when CS transi- tions from low to high. Both devices feature separate set and reset functions that allow the user to turn on or turn off all outputs simul- taneously with a single control line. Built-in hysteresis (Schmidt trigger) on all digital inputs allows this device to be used with slow rising and falling signals, such as those from optocouplers or RC power-up initialization circuits. The MAX4820/MAX4821 are available in 20-pin TSSOP and space-saving 20-pin thin QFN packag