LX1681/1682 are monolithic pulse-width modulator controller ICs, designed to implement a flexible, low cost buck (step-down) regulator supply with minimum external components. The LX1681 is a non-synchronous controller; the LX1682 has a synchronous driver for higher efficiency. The output voltage is adjustable by means of a resistor divider to set the voltage between 1.25V and 4.5V. Short-circuit current limiting can be implemented without expensive current sense resistors. Current is sensed using the voltage drop across the RDS(ON) of the MOSFET — sensing is delayed for 1µs to eliminate MOSFET ringing errors. Hiccup-mode fault protection reduces average power to the power elements during short-circuit conditions. Switching frequency is fixed at 200kHz for optimal cost and space. Under-voltage lockout and soft-start for optimal start-up performance. The LX1681/82 can be disabled by pulling the soft-start pin to ground. Small 8-pin SOIC packaging reduces board space. Optimized for 5V-to-3.3V or 5V-to-2.5V conversion, the LX1681/82 can also be used for other voltage conversions.
The Linfinity LX1681/1682 are monolithic, voltage-mode PWM controllers designed to implement flexible, low-cost step-down regulators with minimal external components. The LX1681 is a non-synchronous controller, while the LX1682 includes a synchronous driver for higher efficiency. Both devices feature a fixed 200kHz switching frequency and an adjustable output voltage between 1.25V and 4.5V.
| Supply Voltage (Vcc) | 4.5V |
|---|---|
| Switching Frequency | 200kHz |
| Output Voltage Range | 1.25V to 4.5V |
| Operating Junction Temperature | -65°C to +150°C |
| Package Type | 8-pin SOIC |
The LX1681 is a non-synchronous controller, while the LX1682 has a synchronous driver for higher efficiency.
The output voltage is adjustable by means of a resistor divider connected to the feedback pin.
No, the devices have internal compensation so that no external compensation is required.