 2010 Microchip Technology Inc.

DS21713L-page 5

24AA32A/24LC32A

2.0

PIN DESCRIPTIONS

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

TABLE 2-1:

PIN FUNCTION TABLE

2.1

A0, A1, A2 Chip Address Inputs

The A0, A1 and A2 inputs are used by the 24XX32A for

multiple device operation. The levels on these inputs

are compared with the corresponding bits in the slave

address. The chip is selected if the comparison is true.

Up to eight devices may be connected to the same bus

by using different Chip Select bit combinations. These

In most applications, the chip address inputs A0, A1

and A2 are hard-wired to logic ‘0’ or logic ‘1’. For

applications in which these pins are controlled by a

microcontroller or other programmable device, the chip

address pins must be driven to logic ‘0’ or logic ‘1’

before normal device operation can proceed. Address

pins are not available in the SOT-23 and chip scale

packages.

2.2

Serial Data (SDA)

SDA is a bidirectional pin used to transfer addresses

and data into and out of the device. It is an open-drain

terminal, therefore, the SDA bus requires a pull-up

 for 100 kHz, 2 k for

400 kHz)

For normal data transfer, SDA is allowed to change

only during SCL low. Changes during SCL high are

reserved for indicating Start and Stop conditions.

2.3

Serial Clock (SCL)

The SCL input is used to synchronize the data transfer

to and from the device.

2.4

Write-Protect (WP)

write operations are inhibited but read operations are

not affected.

Name PDIP SOIC SOIJ TSSOP

Rotated

TSSOP

Description

A0

1

1

1

1

3

1

1

1

—

—

Chip Address Input

A1

2

2

2

2

4

2

2

2

—

—

Chip Address Input

A2

3

3

3

3

5

3

3

3

—

—

Chip Address Input

4

4

4

4

6

4

4

4

2

2

Ground

SDA

5

5

5

5

7

5

5

5

3

5

Serial Address/Data I/O

SCL

6

6

6

6

8

6

6

6

1

4

Serial Clock

WP

7

7

7

7

1

7

7

7

5

3

Write-Protect Input

8

8

8

8

2

8

8

8

4

1

+1.7V to 5.5V Power Supply