User manual

MCP1256/7/8/9 CHARGE PUMP
EVALUATION BOARD USER’S GUIDE
© 2006 Microchip Technology Inc. DS51603A-page 7
Chapter 2. Installation and Operation
2.1 INTRODUCTION
The MCP1256/7/8/9 Charge Pump Evaluation Board demonstrates Microchip’s
MCP1256/7/8/9 devices. The MCP1256/7/8/9 devices are positive regulated charge
pumps that accept an input voltage from +1.8V to +3.6V and convert it to a regulated
3.3V output voltage. The MCP1256/7/8/9 provide a low-cost, compact and simple
solution for step-up DC/DC conversions, primarily in battery applications that do not
want to use switching regulator solutions because of EMI noise and inductor size.
The MCP1256/7/8/9 are designed to offer the highest possible efficiency under
common operating conditions, i.e. V
IN
= 2.4V or 2.8V, V
OUT
= 3.3V, I
OUT
= 100 mA. A
fixed switching frequency, 650 kHz (typically), allows for easy external filtering.
The MCP1256/7 provide a unique SLEEP mode feature. SLEEP mode reduces the
current drawn from the input supply while maintaining a regulated bias on external
peripherals. SLEEP mode can substantially increase battery run-time in portable
applications.
The MCP1258/9 provide a unique BYPASS mode feature. BYPASS virtually eliminates
the current drawn from the input supply by the device, while maintaining an unregulated
bias on external peripherals. BYPASS connects the input supply voltage to the output.
All remaining functions of the device are shutdown. BYPASS mode can substantially
increase battery run-time in portable applications.
The devices supply up to 100 mA of output current for input voltages, V
IN
, greater than
or equal to 2.2V.
2.2 FEATURES
The MCP1256/7/8/9 Charge Pump Evaluation Board is used to evaluate various device
options. Two evaluation circuits are provided as a guide to external component
selection and board layout. Emphasis has been placed on cost, board area, thermal
management and performance. One evaluation circuit utilizes the MCP1256,
demonstrating the SLEEP mode feature along with a power good indication. The other
evaluation circuit utilizes the MCP1259 demonstrating the unique BYPASS mode
feature along with a low-battery indication.
The MCP1256/7/8/9 Charge Pump Evaluation Board has the following features:
• Evaluation of the MCP1256 in a 10-pin MSOP package
• Evaluation of the MCP1259 in a 10-pin MSOP package
• Simple, stand-alone operation
• Powered from external bench supply or compatible battery input
• Surface-mount design
• Fully assembled and tested