Datasheet AD826 (Analog Devices) - 12

AD826 SINGLE SUPPLY OPERATION
R3 and C2 reduce the effect of the power supply changes on the An exciting feature of the AD826 is its ability to perform well in a 1 single supply configuration (see Figure 37). The AD826 is ideally output by low-pass filtering with a corner at . suited for applications that require low power dissipation and high 2πR C 3 2 output current and those which need to drive large capacitive The values for RL and CL were chosen to demonstrate the loads, such as high speed buffering and instrumentation. AD826’s exceptional output drive capability. In this configura- Referring to Figure 36, careful consideration should be given to tion, the output is centered around 2.5 V. In order to eliminate the proper selection of component values. The choices for this the static dc current associated with this level, C3 was inserted particular circuit are: (R1 + R3)储R2 combine with C1 to form a in series with RL. low frequency corner of approximately 30 Hz.
VS 500mV 100 R3 90 1k 3.3 F C2 0.1 F 0.01 R1 F 9k 10 1/2 COUT C1 0% AD826 VOUT 1 F VIN RL CL 500mV 100ns R2 150 200pF 10k C3 0.1 F
Figure 37. Single Supply Pulse Response, G = +1, R Figure 36. Single Supply Amplifier Configuration L = 150 Ω, CL = 200 pF
1k PARALLEL AMPS PROVIDE 100 mA TO LOAD V 1 F
By taking advantage of the superior matching characteristics of
S
the AD826, enhanced performance can easily be achieved by employing the circuit in Figure 38. Here, two identical cells are
0.1 F
paralleled to obtain even higher load driving capability than that
1k R1
of a single amplifier (100 mA min guaranteed). R1 and R2 are
5 1/2
included to limit current flow between amplifier outputs that
AD826
would arise in the presence of any residual mismatch.
VIN VOUT RL R2 5 1/2 1k AD826 0.1 F –V 1 F S 1k
Figure 38. Parallel Amp Configuration REV. C –11–