Simplified Block Diagram
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- Wide Operating Input Voltage Range: +35V to +72V
- IEEE® 802.3af Compatible
- Four Independent Power Switch Controllers
- Open-Circuit Detector
- On-Board Charge Pumps to Drive External n-Channel FETs
- Current Sense with External Resistor
- Foldback Current Limiting
- +32V Input Undervoltage Lockout
- On-Chip +12V, 100mA Voltage Relay Drivers
- IP Phone Switches/Routers
- Midspan Power-Over-MDI
- Network Switches/Routers
- Telecom Line Cards
The MAX5913A/MAX5914A feature an internal undervoltage lockout (UVLO) function that prevents the FET from turning on, if VCC does not exceed the default value of +32V. The devices also feature a +12V relay driver with 100mA current drive capable of driving low-voltage +3.3V relays. The MAX5913A features an active-low relay driver that sinks current when the relay output is enabled. The MAX5914A features an active-high relay driver output that sources 1mA to drive an external FET relay driver when the relay output is enabled. Control circuitry ensures the relays and the FETs are off until VCC reaches the UVLO threshold. The MAX5913A/MAX5914A use an external sense resistor to enable all the internal current-sense functions.
The MAX5913A/MAX5914A feature a programmable analog current-limit circuit. If the switch remains in current limit for more than a programmable time, the n-channel FET latches off and the supply can be restarted either by autoretry or by an external command after the preset off-time has elapsed.
The MAX5913A/MAX5914A are available in a 44-pin MQFP package and are specified for the extended -40°C to +85°C operating temperature range.