The MAX1846/MAX1847 high-efficiency PWM inverting controllers allow designers to implement compact, low-noise, negative-output DC-DC converters for telecom and networking applications. Both devices operate from +3V to +16.5V input and generate -500mV to -200V output. To minimize switching noise, both devices feature a current-mode, constant-frequency PWM control scheme. The operating frequency can be set from 100kHz to 500kHz through a resistor. The MAX1846 is available in an ultra-compact 10-pin µMAX® package. Operation at high frequency, compatibility with ceramic capacitors, and inverting topology without transformers allow for a compact design. Compatibility with electrolytic capacitors and flexibility to operate down to 100kHz allow users to minimize the cost of external components. The high-current output drivers are designed to drive a P-channel MOSFET and allow the converter to deliver up to 30W. The MAX1847 features clock synchronization and shutdown functions. The MAX1847 can also be configured to operate as an inverting flyback controller with an N-channel MOSFET and a transformer to deliver up to 70W. The MAX1847 is available in a 16-pin QSOP package. Current-mode control simplifies compensation and provides good transient response. Accurate current-mode control and over current protection are achieved through low-side current sensing.
The MAX1846 and MAX1847 are high‑efficiency PWM inverting controllers designed for compact, low‑noise, negative‑output DC‑DC converters used in telecom, networking, and automotive power supplies. Both devices operate from a 3 V to 16.5 V input and generate a -0.5 V to -200 V output, with switching frequencies selectable between 100 kHz and 500 kHz.
The datasheet includes absolute maximum ratings, detailed electrical characteristics, pin descriptions, package information, and typical application circuits. It also lists ordering information for the 10‑pin UMAX package (MAX1846) and the 16‑pin QSOP package (MAX1847), along with efficiency figures up to 90 % and output power capabilities of up to 30 W (MAX1846) or 70 W (MAX1847).
| Operating Input Voltage Range | 3 V to 16.5 V |
|---|---|
| Switching Frequency Range | 100 kHz to 500 kHz |
| Typical Efficiency | 90 % |
| MAX1846 Package | 10‑pin UMAX® |
| MAX1847 Package | 16‑pin QSOP |
| Maximum Output Power (MAX1846) | 30 W |
The devices operate from 3 V to 16.5 V input.
Typical efficiency is about 90 %.
The switching frequency can be set between 100 kHz and 500 kHz.