REV. B

AD826

–11–

SINGLE SUPPLY OPERATION

An exciting feature of the AD826 is its ability to perform well in a

single supply configuration (see Figure 37). The AD826 is ideally

suited for applications that require low power dissipation and high

output current and those which need to drive large capacitive

loads, such as high speed buffering and instrumentation.

Referring to Figure 36, careful consideration should be given to

the proper selection of component values. The choices for this

particular circuit are: (R1 + R3) R2 combine with C1 to form a

low frequency corner of approximately 30 Hz.

1/2

AD826

R2

10k

3.3 F

0.01 F

C3

0.1 F

R1

9k

R3

1k

C2

0.1 F

C1

1 F

200pF

150

Figure 36. Single Supply Amplifier Configuration

R3 and C2 reduce the effect of the power supply changes on the

output by low-pass filtering with a corner at

1

2

πR

.

AD826’s exceptional output drive capability. In this configura-

tion, the output is centered around 2.5 V. In order to eliminate

the static dc current associated with this level, C3 was inserted

10

90

100

0%

500mV

100ns

500mV

Figure 37. Single Supply Pulse Response, G = +1,

PARALLEL AMPS PROVIDE 100 mA TO LOAD

By taking advantage of the superior matching characteristics of

the AD826, enhanced performance can easily be achieved by

employing the circuit in Figure 38. Here, two identical cells are

paralleled to obtain even higher load driving capability than that

of a single amplifier (100 mA min guaranteed). R1 and R2 are

included to limit current flow between amplifier outputs that

would arise in the presence of any residual mismatch.

1k

R1

5

R2

5

1k

1k

1k

1/2

AD826

1/2

AD826

0.1 F

1 F

0.1 F

1 F

Figure 38. Parallel Amp Configuration