LM5642MH

• Two synchronous step-down regulators
• 180° phase operation
• Fixed nominal frequency of 200 kHz: LM5642
• Fixed nominal frequency of 375 kHz: LM5642X
• From 150 kHz synchronous switching frequency LM5642 at 250 kHz and LM5642X from 200 kHz to 500 kHz
• 4.5V to 36V input range
• The shutdown current is 50μA
• Adjustable output from 1.3V to 90% of VIN
• 0.04% (typical) line and load regulation accuracy
• Current mode control with or without inductive resistors
• Separate enable/soft-start pins allow for simple sequential start configuration.
• Configurable to operate in parallel with a single output. (See.) ）
• Adjustable cycle-by-cycle current limit
• Enter the undervoltage lock
• Output overvoltage latching protection
• Output undervoltage protection with delay
• Thermal shutdown
• Self-discharge when the regulator of the output capacitor is turned off
• TSSOP and eTSSOP (exposed pad) packages

illustrate

The LM5642 series includes two current-mode synchronous buck regulator controllers with 180° phases of the LM5642 at 375kHz and the normal switching frequency at 200kHz LM5642X.

The phase operation reduces the input RMS ripple current, which greatly reduces the input capacitance required. The switching frequency can be synchronized to the LM5642 between 150 kHz and the external clock of 200 kHz and 500 kHz LM5642X between 250 kHz. The two switching regulator outputs can also be operated in parallel as a two-phase, single-output regulator.

The output of each channel can be adjusted independently from 1.3V to 90% of VIN. The internal 5V rail can also be externally driven bootstrap circuit.

Current mode feedback control ensures excellent line and load regulation and excellent wide loop bandwidth for fast load transients. The current is a crossing of the top FET of the Vds or the drain of the top FET connected in series to an external current sense resistor.

The LM5642 features a soft-start circuit that simulates a soft-start circuit with independent output loads and output capacitors, making the soft-start behavior more predictable and controllable than traditional soft-start circuits.

Two outputs overvoltage protection. A UV delay pin can also allow a delayed shutdown time of the IC based on the output voltage event period.

apply

• Embedded computer systems
• navigation system
• telecommunications systems
• Stb
• WebPAD
• Point load power architecture