8

®

OPA337, OPA2337

OPA338, OPA2338

Figure 4 shows a compensation technique using an inverting

configuration. The low frequency gain is set by the resistor

ratio while the high frequency gain is set by the capacitor

ratio. As with the noninverting circuit, for frequencies above

stable gain for the op amp.

The capacitor values shown are the nearest standard values.

Capacitor values may need to be adjusted slightly to opti-

mize performance. For more detailed information, consult

the OPA686 product data sheet.

Figure 5 shows the large-signal transient response using the

circuit given in Figure 4. As shown, the OPA338 is stable in

low gain applications and provides improved slew rate

performance when compared to the OPA337.

FIGURE 4. Inverting Compensation Circuit of OPA338 for

Low Gain.

OPA338

2

µs/div

FIGURE 5. G = 2, Slew-Rate Comparison of OPA338 and

OPA337.

OPA337

For a desired dc gain of 2 and high frequency gain of 10, the

following resistor and capacitor values result:

TYPICAL APPLICATION

Figure 6 shows the OPA2337 in a typical application. The

ADS7822 is a 12-bit, micro-power sampling analog-to-

digital converter available in the tiny MSOP-8 package. As

with the OPA2337, it operates with a supply voltage as

low as +2.7V. When used with the miniature SOT23-8

package of the OPA2337, the circuit is ideal for space-

limited and low power applications. In addition, OPA2337’s

high input impedance allows large value resistors to be

used which results in small physical capacitors, further

reducing circuit size. For further information, consult the

ADS7822 product data sheet.

C

, C

1

2

πf

C

1

150pF

OPA338

V

IN

V

OUT

R

1

5k

Ω

R

2

10k

Ω

Where G

G

Improved slew rate versus OPA337

(see Figure 5).

C

2

15pF