Datasheet Maxim MAX1771 — 数据表

EVALUATION KIT AVAILABLE MAX1771 LE AVAILAB 12V or Adjustable, High-Efficiency,
Low IQ, Step-Up DC-DC Controller
General Description
The MAX1771 step-up switching controller provides
90% efficiency over a 30mA to 2A load. A unique current-limited pulse-frequency-modulation (PFM) control
scheme gives this device the benefits of pulse-widthmodulation (PWM) converters (high efficiency at heavy
loads), while using less than 110µA of supply current (vs.
2mA to 10mA for PWM converters).
This controller uses miniature external components. Its
high switching frequency (up to 300kHz) allows surface-mount magnetics of 5mm height and 9mm diameter. It accepts input voltages from 2V to 16.5V. The
output voltage is preset at 12V, or can be adjusted
using two resistors.
The MAX1771 optimizes efficiency at low input voltages
and reduces noise by using a single 100mV current-limit
threshold under all load conditions. A family of similar
devices, the MAX770–MAX773, trades some full-load
efficiency for greater current-limit accuracy; they provide
a 200mV current limit at full load, and switch to 100mV
for light loads.
The MAX1771 drives an external N-channel MOSFET
switch, allowing it to power loads up to 24W. If less power
is required, use the MAX756/MAX757 or MAX761/MAX762
step-up switching regulators with on-board MOSFETs. An …