The MAX8545/MAX8546/MAX8548 are voltage-mode pulse-width-modulated (PWM), step-down DC-DC controllers ideal for a variety of cost-sensitive applications. They drive low-cost n-channel MOSFETs for both the high-side switch and synchronous rectifier, and require no external current-sense resistor. These devices can supply output voltages as low as 0.8V. The MAX8545/MAX8546/MAX8548 have a wide 2.7V to 28V input range, and do not need any additional bias voltage. The output voltage can be precisely regulated from 0.8V to 0.83 x VIN. These devices can provide efficiency up to 95%. Lossless short-circuit and current-limit protection is provided by monitoring the RDS(ON) of the low-side MOSFET. The MAX8545 and MAX8548 have a current-limit threshold of 320mV, while the MAX8546 has a current-limit threshold of 165mV. All devices feature foldback-current capability to minimize power dissipation under short-circuit condition. Pulling the COMP/EN pin low with an open-collector or low-capacitance, open-drain device can shut down all devices. The MAX8545/MAX8546 operate at 300kHz and the MAX8548 operates at 100kHz. The MAX8545/MAX8546/MAX8548 are compatible with low-cost aluminum electrolytic capacitors. Input undervoltage lockout prevents proper operation under power-sag operations to prevent external MOSFETs from overheating. Internal soft-start is included to reduce inrush current. These devices are offered in space-saving 10-pin µMAX® packages.
The MAX8545, MAX8546, and MAX8548 are voltage‑mode PWM step‑down DC‑DC controllers designed for cost‑sensitive applications. They drive low‑cost n‑channel MOSFETs for both the high‑side switch and synchronous rectifier, eliminating the need for an external current‑sense resistor. The devices support a wide 2.7 V to 28 V input range and can regulate output voltages from 0.8 V up to 0.83 × VIN.
Key features include up to 95 % efficiency, foldback short‑circuit protection, lossless over‑current protection, and selectable switching frequencies of 300 kHz (MAX8545/MAX8546) or 100 kHz (MAX8548). The controllers are offered in a space‑saving 10‑pin µMAX package and operate over –40 °C to +85 °C.
| Input Voltage Range | 2.7 V to 28 V |
|---|---|
| Output Voltage Range | 0.8 V to 0.83 × VIN |
| Switching Frequency | 300 kHz (MAX8545/MAX8546), 100 kHz (MAX8548) |
| Current‑Limit Threshold | 320 mV (MAX8545/MAX8548), 165 mV (MAX8546) |
| Efficiency | up to 95 % |
| Package | 10‑pin µMAX |
| Operating Temperature Range | -40 °C to +85 °C |
The devices operate from 2.7 V to 28 V input.
The MAX8545 (and MAX8546) operate at 300 kHz.
Pull the COMP/EN pin low with an open‑collector or open‑drain device.