MCP1256/7/8/9
Regulated 3.3V, Low-Ripple Charge Pump with Low-
Operating Current SLEEP Mode or BYPASS Mode
Features
• Inductorless 1.5x, 2x Boost DC/DC Converter
• Output Voltage: 3.3V
• High Output Voltage Accuracy:
- ±3.0% (VOUT Fixed)
www.DataShe•etO4Uut.cpuotmCurrent Up To 100 mA
• 20 mVPP Output Voltage Ripple
• Thermal Shutdown and Short Circuit Protection
• Uses Small Ceramic Capacitors
• Switching Frequency: 650 kHz
• Low-Power SLEEP Mode: MCP1256/7
• BYPASS Mode: MCP1258/9
• Low-Power Shutdown Mode: 0.1 μA (Typical)
• Shutdown Input Compatible with 1.8V Logic
• VIN Range: 1.8V to 3.6V
• Soft-Start Circuitry to Minimize Inrush Current
• Temperature Range: -40°C to +125°C
• Packaging:
- 10-Pin, 3 mm x 3 mm DFN
- 10-Pin, MSOP
Applications
• Pagers
• Portable Measurement Instruments
• Home Automation Products
• PICmicro® MCU Bias
Typical Application
INPUT
1.8V to 3.6V
CIN
10 μF
C1
1 μF
ON / OFF
MCP1256
7 VIN VOUT 5
10 SHDN
PGOOD
1
4 C1+
8 C1-
C2+ 6
C2- 3
2 SLEEP
GND
9
R1
C2
1 μF
OUTPUT
3.3V
COUT
10 μF
Power-Good
Indication
Typical Application with Power-Good Indication
Description
The MCP1256, MCP1257, MCP1258 and MCP1259
are inductorless, positive regulated charge pump
DC/DC converters. The devices generate a regulated
3.3V output voltage from a 1.8V to 3.6V input. The
devices are specifically designed for applications
operating from 2-cell alkaline, Ni-Cd, or Ni-MH
batteries or by one primary lithium MnO2 (or similar)
coin cell battery.
The MCP1256, MCP1257, MCP1258 and MCP1259
provide high efficiency by automatically switching
between 1.5x and 2x boost operation. In addition, at
light output loads, the MCP1256 and MCP1257 can be
placed in a SLEEP mode, lowering the quiescent
current while maintaining the regulated output voltage.
Alternatively, the MCP1258 and MCP1259 provide a
BYPASS feature connecting the input voltage to the
output. This allows for real-time clocks,
microcontrollers or other system devices to remain
biased with virtually no current being consumed by the
MCP1258 or MPC1259.
In normal operation, the output voltage ripple is below
20 mVPP at load currents up to 100 mA. Normal opera-
tion occurs at a fixed switching frequency of 650 kHz,
avoiding interference with sensitive IF bands.
The MCP1256 and MCP1258 feature a power-good
output that can be used to detect out-of-regulation
conditions. The MCP1257 and MCP1259 feature a low-
battery indication that issues a warning if the input
voltage drops below a preset voltage threshold.
Extremely low supply current and few external parts (4
capacitors) make these devices ideal for small, battery-
powered applications. A Shutdown mode is also
provided for further power reduction.
The devices incorporate thermal and short-circuit pro-
tection. Two package offerings are provided: 10-pin
MSOP and 10-lead 3 mm x 3 mm DFN. The devices
are completely characterized over the junction temper-
ature range of -40°C to +125°C.
© 2006 Microchip Technology Inc.
DS21989A-page 1
