© 2002 Microchip Technology Inc.

DS21375B-page 3

TC1264

2.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1:

PIN FUNCTION TABLE

3.0

DETAILED DESCRIPTION

The TC1264 is a precision, fixed output LDO. Unlike

bipolar regulators, the TC1264’s supply current does

remains stable and within regulation over the entire

consideration in RTC and CMOS RAM battery back-up

applications).

Figure 3-1 shows a typical application circuit.

FIGURE 3-1:

TYPICAL APPLICATION

CIRCUIT

3.1

Output Capacitor

A1

The output capacitor should have an effective series

resistance greater than 0.1

Ω and less than 5Ω.A 1µF

is more than 10 inches of wire between the regulator

and the AC filter capacitor, or if a battery is used as the

power source. Aluminum electrolytic or tantalum

capacitor types can be used. (Since many aluminum

electrolytic capacitors freeze at approximately -30°C,

solid tantalums are recommended for applications

operating below -25°C.) When operating from sources

other

than

batteries,

supply-noise

rejection

and

transient response can be improved by increasing the

value of the input and output capacitors and employing

passive filtering techniques.

Pin No.

(3-Pin SOT-223)

(3-Pin TO-220)

(3-Pin DDPAK)

Symbol

Description

Unregulated supply input.

2

GND

Ground terminal.

Regulated voltage output.

C1

1

µF

Battery

TC1264

C2

1

µF

GND

+

+

+

–