MP5491 Laser Diode Current Source IC WLCSP-36

MP5491 Laser Diode Current Source IC WLCSP-36

The MP5491 integrates four high-accuracy current sources for laser diodes (LDs), which makes this device well-suited for the transmitter optical subassembly (TOSA) of quad, small form-factor pluggable (QSFP) optical modules.

Key Specifications

Features

• 4-Channel Accurate Current Source
• Configurable Current for 10-Bit Digital-to- Analog Converter (DAC)
• Up to 250mA Current per Channel
• Configurable Current Source Slew Rate
• Output Discharging for the Disabled IDx Pin(s)
• Current Source Output Short-Circuit Protection (SCP)
• 6-Channel Independent GPO Outputs
• I2C Control Interface
• I2C Hardware Reset (HRESET)
• Available in a WLCSP-36 (3mmx4.25mm) Package

Typical Application Circuit

Design Notes

• Rail sequencing order and delay are part of the SoC power-up contract; a wrong order latches the processor even though every rail is in spec.
• In multiphase designs, current balance depends on the loop matching between phases, so keep the layout symmetric.
• Digital interfaces (PMBus, I²C) need pull-ups to the correct rail and a defined state during power-up.
• Thermal design is a system problem here: the PMIC sits next to the load it feeds, so budget the shared copper, not the package alone.

Common Questions