2006 Microchip Technology Inc.
DS21989A-page 1
MCP1256/7/8/9
Features
Inductorless 1.5x, 2x Boost DC/DC Converter
Output Voltage: 3.3V
High Output Voltage Accuracy:
- ±3.0% (V
OUT
Fixed)
Output Current Up To 100 mA
20 mV
PP
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
μ
A (Typical)
Shutdown Input Compatible with 1.8V Logic
V
IN
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
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
microcontrollers or other system devices to remain
biased with virtually no current being consumed by the
MCP1258 or MPC1259.
for
real-time
clocks,
In normal operation, the output voltage ripple is below
20 mV
PP
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.
PGOOD
GND
SHDN
1
2
3
4
MCP1256
V
OUT
5
6
7
8
9
10
V
IN
SLEEP
C
IN
10
μ
F
C
OUT
10
F
C
1
-
C
1
+
C
1
1
μ
F
C
2
-
C
2
+
C
2
1
μ
F
R
1
INPUT
OUTPUT
3.3V
Power-Good
Indication
ON / OFF
Typical Application with Power-Good Indication
Regulated 3.3V, Low-Ripple Charge Pump with Low-
Operating Current SLEEP Mode or BYPASS Mode