User manual

Installation and Operation

2.3.2 Shutdown Mode (SHDN)

Driving SHDN low puts the MCP1256/7/8/9 in a low-power Shutdown mode. This

disables the charge-pump switches, oscillator and control logic, reducing the quiescent

current to 0.1 μA (typical). The PGOOD output and LBO

are in a high impedance state

during shutdown.

2.3.3 SLEEP Mode (SLEEP)

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 regulation control is hysteretic, otherwise referred to as a bang-bang control. The

output is regulated around a fixed reference with some hysteresis. As a result, some

amount of peak-to-peak ripple will be observed at the output independent of load

current. The frequency of the output ripple, however, will be influenced heavily by the

load current and output capacitance.

2.3.4 BYPASS Mode (BYPASS)

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.

2.3.5 Device Support Options

The MCP1256/7/8/9 Charge Pump Evaluation Board supports the entire

MCP1256/7/8/9 family. The MCP1256/7/8/9 Charge Pump Evaluation Board is

provided with two evaluation circuits utilizing the MCP1256 and MCP1259. Alternate

devices can be substituted in order to evaluate the different MCP1256/7/8/9 family

options.