TC1142 데이터 시트보기 (PDF) - Microchip Technology

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TC1142

Inductorless -2x Boost/Buck Regulator

Microchip Technology 

M

TC1142

Inductorless -2x Boost/Buck Regulator

Features

• Input Range 2.5V to 5.5V

• Regulated Output Options from -3.0 to -5.0V

• Output Current 20mA (max)

• 200kHz Internal Oscillator Frequency

• External Synchronizing Clock Input

• Logic Level Shutdown

- 1µA (max) Supply Current

• Available in 8-Pin MSOP Package

Applications

• Cellular Phones

• Battery Powered/Portable Equipment

Device Selection Table

Part

Number

Output

Voltage Package

(V)*

Operating

Temp.

Range

TC1142-3.0EUA 3.0 8-Pin MSOP -40°C to +85°C

TC1142-4.0EUA 4.0 8-Pin MSOP -40°C to +85°C

TC1142-5.0EUA 5.0 8-Pin MSOP -40°C to +85°C

*Other output voltages are available (-3.5V and -4.5V). Please

contact Microchip Technology Inc. for details.

Functional Block Diagram

+

– 5.5V to 2.5V

ON OFF

VIN

CCLK

VOUT

OSC 0.47µF C1 TC1142-50

OVERRIDE

–2x Boost/Buck

VOUT = -5.0V

4.7µF

COUT

0.47µF C2

GND

Package Type

8-Pin MSOP

VOUT 1

C2– 2

C2+ 3

C1– 4

TC1142

8 CCLK

7 VIN

6 C1+

5 GND

General Description

The TC1142 generates a regulated negative voltage

from -3V to -5V at 20mA from an input of 2.5V to 5.5V,

using only three external capacitors. Other boost/buck

switching regulators must use an inductor, which is

larger and radiates EMI. An internal voltage

comparator inhibits the charge pump when VOUT is

more negative than the regulated value (per the

ordering option). The values of flying capacitors C1 and

C2 are chosen to be less than COUT in order to reduce

the ripple generated from regulating VOUT in this

manner. The TC1142 also can be used as a -1x buck

regulator by omitting C2, and connecting the C2 pin to

VOUT.

The part goes into shutdown when the CCLK input is

driven low. When in shutdown mode, the part draws a

maximum of 1µA. When CCLK is pulled high, the part

runs from the internal 200kHz oscillator. The device

may be run with an external clock, provided the

frequency is greater than 3kHz and less than 500kHz.

The TC1142 comes in a space-saving MSOP package.

+

– 5.5V to 3V

ON OFF

VIN

CCLK

VOUT

OSC 0.47µF C1 TC1142-30

OVERRIDE

C2–

GND

–1x Buck

VOUT = –3.0V

4.7µF

COUT

 2002 Microchip Technology Inc.

DS21360B-page 1

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