MAX4822 +3.3V/+5V, 8-Channel, Relay Drivers with Fast Recovery Time and Power-Save Mode
The MAX4822–MAX4825 8-channel relay drivers offer built-in kickback protection and drive +3V/+5V nonlatching or dual-coil-latching relays. Each independent open-drain output features a 2.7Ω (typ) on-resistance and is guaranteed to sink 70mA (min) of load current. These devices consume less than 300µA (max) quiescent current and have 1µA output off-leakage current. A Zener-kickback-protection circuit significantly reduces recovery time in applications where switching speed is critical.
The MAX4822/MAX4824 feature a unique power-save mode where the relay current, after activation, can be reduced to a level just above the relay hold-current threshold. This mode keeps the relay activated while significantly reducing the power consumption.
The MAX4822/MAX4823 feature a 10MHz SPI™-/QSPI™-MICROWIRE™-compatible serial interface. Input data is shifted into a shift register and latched to the outputs when active-low CS transitions from low to high. Each data bit in the shift register corresponds to a specific output, allowing independent control of all outputs.
The MAX4824/MAX4825 feature a 4-bit parallel-input interface. The first 3 bits (A0, A1, A2) determine 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 active-low CS transitions from low to high.
The MAX4822–MAX4825 feature separate set and reset functions, allowing turn-on or turn-off of all outputs simultaneously with a single control line. Built-in hysteresis (Schmidt trigger) on all digital inputs allows these devices to be used with slow-rising and falling signals, such as those from optocouplers or RC power-up initialization circuits. The MAX4822–MAX4825 are available in space-saving 4mm x 4mm, 20-pin thin QFN packages. They are specified over the -40°C to +85°C extended temperature range.
- ATE Equipment
- DSL Redundancy Protection (ADSL/VDSL/HDSL)
- Industrial Equipment
- T1/E1 Redundancy Protection
- T3/E3 Redundancy Protection
- Test Equipment (Oscilloscopes, Spectrum Analyzers)
Features and Benefits
- Built-In Zener Kickback Protection for Fast Recovery
- Programmable Power-Save Mode Reduces Relay Power Consumption (MAX4822/MAX4824)
- 10MHz SPI-/QSPI-/MICROWIRE-Compatible Serial Interface
- Eight Independent Output Channels
- Drive +3V and +5V Relays
- Guaranteed 70mA (min) Coil Drive Current
- Guaranteed 5Ω (max) RON
- Active-Low SET/Active-Low RESET Functions to Turn On/Off All Outputs Simultaneously
- Serial Digital Output for Daisy Chaining
- Optional Parallel Interface (MAX4824/MAX4825)
- Low 300µA (max) Quiescent Supply Current
- Space-Saving, 4mm x 4mm, 20-Pin TQFN Package