MAX1800

Obsolete

Digital Camera Step-Up Power Supply

Complete Power-Supply Solution for Digital Camera Delivers 5 Outputs from 1 Li+ or 2-3 AA Cells

Data Sheet (Rev. 0) Product Selection Table

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Overview

+0.7V to +5.5V Input Voltage Range
Main DC-DC Converter
- 95% Efficiency
- +2.7V to +5.5V Adjustable Output Voltage
- 1.5A Load Current
Uncommitted Gain Block for Linear Regulator
Three Independent Auxiliary Step-Up Controllers
- Adjustable Maximum Duty Cycle
Oscillator and Reference Outputs to Drive External Slave Controllers (MAX1801)
Power-Ready Output
Up to 1MHz Switching Frequency
1µA Supply Current in Shutdown Mode
Internal Soft-Start Control
Overload Protection for all DC-DC Converters
Compact 32-Pin TQFP Package (5mm x 5mm body)

The MAX1800 provides a complete power-supply solution for digital still cameras and video cameras. The device integrates a high-efficiency main step-up DC-DC converter, three auxiliary step-up controllers, and an uncommitted gain block that drives an external P-channel MOSFET for a linear regulator. The MAX1800 is targeted for applications that use either two or three primary cells or a single lithium-ion (Li+) battery.

The main DC-DC converter accepts inputs from +0.7V to +5.5V and regulates a resistor-adjustable output from 2.7V to 5.5V. It uses an internal synchronous rectifier to regulate the output with 95% efficiency. An adjustable operating frequency facilitates designs for optimum size, cost, and efficiency.

The auxiliary step-up controllers can be used to power a digital camera's CCD, LCD, and backlight. The MAX1800 also features expandability by supplying power, oscillator signal, and reference to the MAX1801, a low-cost slave DC-DC controller that supports step-up, SEPIC, and fly-back configurations.

The MAX1800 is available in a space-saving 32-pin TQFP package (5mm x 5mm body), and the MAX1801 is available in an 8-pin SOT package. An evaluation kit (MAX1800EVKIT) featuring both devices is available to expedite designs.

Applications