MIC5400

Micrel

MIC5400

2

November 2002

Pin Description

Pin Number

Pin Name

Pin Function

Pin

Name

Function

1,2,3,4

A4,A3,A2,A1

Current Sink pins to be connected to LED cathodes

5

LOAD

If this pin is Low, the device acts as a shift register. When this pin is High,

only the first falling edge of the clock transfers data from the Shift-Register to

the Parallel Register. The next rising edge transfers data from the Status

Register to the Shift Register

6

SHFTCLK

Shift-register Clock Input

7

VDD

Positive Supply Voltage

8,22

GND

Ground

9

SHIFTIN

Shift-register Data Input

10

SHIFTOUT

Shift-register Data Output

11,12,13,14

B1,B2,B3,B4

Current Sink pins to be connected to LED cathodes

15,16,17,18

B5,B6,B7,B8

Current Sink pins to be connected to LED cathodes

19

VDDB

Analog Power source pins which provide current sense points for Channel A

and Channel B PNP emitter currents, independently.

20

BD_B

Base Drive Outputs for external PNP transistors. Feedback Loop compensa-

tion requires one external capacitor at each PNP transistor collector.

21

REF

Reference current output. Must be connected to an external resistor to set

the maximum current for the current sink outputs.

23

BD_A

Base Drive Outputs for external PNP transistors. Feedback Loop compensa-

tion requires one external capacitor at each PNP transistor collector.

24

VDDA

Analog Power source pins which provide current sense points for Channel A

and Channel B PNP emitter currents, independently.

25,26,27,28

A8,A7,A6,A5

Current Sink pins to be connected to LED cathodes

Pin Configuration

1

A4

A3

A2

A1

LOAD

SHFTCLK

VDD

GND

SHIFTIN

SHIFTOUT

28 A5

A6

A7

A8

VDDA

BD_A

GND

IREF

BD_B

VDDB

27

26

25

24

23

22

21

20

19

2

3

4

5

6

7

8

9

10

B1

B8

18

11

B2

B7

17

12

B3

B6

16

13

B4

B5

15

14

28-Lead SOIC