ADD8504/ADD8505/ADD8506

Rev. D | Page 7 of 12

APPLICATIONS INFORMATION

The ADD8504/ADD8505/ADD8506 have CMOS buffers with

A/B inputs to select between two different reference voltages set

up by an external resistor ladder. Input bias currents are orders

of magnitude less than competitive parts. This allows the use of

a very large resistor ladder to save supply current.

The buffer outputs are designed to drive resistive or capacitive

loads. Therefore, to attain the best display performance, do not

use resistors in series with these outputs. Outputs have high

slew rates and 6 μs settling times. Each output delivers a mini-

mum of 120 mA, ensuring a fast response to varying loads.

Power supply pins on the ADD8505 and ADD8506 have

multiple ground (GND) and supply (VCC) connections.

Because of the high peak currents that these buffers deliver, it

is recommended that all GND and VCC pins be connected and

suitably bypassed.

Table 6. Mux Function

A/B Select

Input

Logic High

INAx

Logic Low

INBx

RB1

RB2

RB3

RB4

RB5

RB6

5V

5V

RB7

RA1

RA2

RA3

RA4

RA5

RA6

RA7

0.1

μF

0.1

μF

NOTES

1. RAx RESISTORS ARE USED TO SET POSITIVE INVERSION GAMMA VOLTAGES.

2. RBx RESISTORS ARE USED TO SET NEGATIVE INVERSION GAMMA VOLTAGES.

2

23

24

TO COLUMN

DRIVERS

VCOM

(INVERTING SIGNAL)

5V

0.1

μF

1

3

22

4

21

5

20

6

19

7

18

8

17

9

16

10

15

10

10

14

11

12

13

Figure 12. ADD8506 Typical Application