TLC7226C, TLC7226I, TLC7226M

QUADRUPLE 8BIT DIGITALTOANALOG CONVERTERS

SLAS060F − JANUARY 1995 − REVISED APRIL 2009

11

POST OFFICE BOX 655303

APPLICATION INFORMATION

bipolar output operation using external amplifier

Each of the DACs of the TLC7226 can also be individually configured to provide bipolar output operation, using

an external amplifier and two resistors per channel. Figure 9 shows a circuit used to implement offset binary

coding (bipolar operation) with DAC A of the TLC7226. In this case:

V

O +

1

) R2

R1

D

A

V

ref *

R2

R1

V

ref

with R1

+ R2

V

O +

2D

A *

1

V

ref

where D

A

is a fractional representation of the digital word in latch A.

(2)

Mismatch between R1 and R2 causes gain and offset errors. Therefore, these resistors must match and track

over temperature. The TLC7226 can be operated with a single power supply or from positive and negative

power supplies.

15 V

_

+

DAC A

TLC7226

2

4

R2†

R1†

VO

REF

† R1 = R2 = 10 kΩ ±0.1%

_

+

− 15 V

Figure 9. Bipolar Output Circuit

staircase window comparator

In many test systems, it is important to be able to determine whether some parameter lies within defined limits.

the TLC7226. Each adjacent pair of comparators forms a window of programmable size (see Figure 11). When

applied to the REF input, the minimum window size is 10 mV.