- Two synchronous buck regulators
- 180 ° out-of-phase operation
- 4.5V to 30V input range
- Chapter 1 Power monitoring is good
- 37μA shutdown current
- 0.04% (typical) line and load regulation error
- With or without sense resistor current mode control
- A separate enable/soft-start pin allows for simple sequential startup configuration.
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Can be configured for single-output parallel operation. (See ).
- Adjustable cycle-by-cycle current limit
- Input undervoltage lockout
- Output overvoltage lockout protection
- Output undervoltage protection and delay
- Thermal shutdown
- When the self-discharge regulator of the output capacitor is off,
- TSSOP package
illustrate
The LM2642 consists of two current mode synchronous buck switching clocks at a regulated controller of 300kHz.
The two switching regulator controllers operate 180° out of phase. This feature reduces the input ripple RMS current, which greatly reduces the input capacitance required. The two switching regulator outputs can also be paralleled as a dual-phase single-output regulator.
Each channel output can be independently adjusted from 1.3reachV IN • Maximum duty cycle. The internal 5V supply can also be used to drive an external bootstrap circuit.
Current-mode feedback control guarantees excellent line and load regulation with excellent fast load transient response and wide loop bandwidth. Either an external current sense resistor in the current top or FET Vds is connected in series with the top FET's drain induction. The current limit is independently adjustable for each channel.
The LM2642 soft-start circuit with analog functions is independent of output load and output capacitance. This makes soft-start behavior more predictable than traditional soft-start circuit control.
The PGOOD1 pin monitors the Channel 1 DC output. Overvoltage protection is available for both outputs. An ultraviolet delay pin also allows the IC time to output undervoltage events during delayed shutdown.
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