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 -2V 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, current‑mode PWM controllers that generate negative output voltages for telecom and networking power supplies. They operate from a 3.0 V to 16.5 V input and can produce -2 V to -200 V output, delivering up to 30 W (MAX1846) or 70 W (MAX1847) while maintaining about 90 % efficiency.
The devices feature programmable switching frequency (100 kHz‑500 kHz), internal soft‑start, over‑current protection, and optional synchronization to an external clock. They are offered in compact 10‑pin UMAX and 16‑pin QSOP packages and are compatible with both ceramic and electrolytic output capacitors.
| Operating Input Voltage Range | 3.0 V – 16.5 V |
|---|---|
| Output Voltage Range | -2 V to -200 V |
| Switching Frequency | 100 kHz – 500 kHz |
| Efficiency | ≈90 % |
| Maximum Output Power (MAX1846) | 30 W |
| Maximum Output Power (MAX1847) | 70 W |
The devices operate from 3.0 V to 16.5 V input.
The switching frequency is programmable between 100 kHz and 500 kHz.
The MAX1847 can deliver up to 70 W of output power.