10

®

OPA237, 2237, 4237

APPLICATIONS INFORMATION

OPA237 series op amps are unity-gain stable and suitable

for a wide range of general-purpose applications. Power

supply pins should be bypassed with 10nF ceramic capaci-

tors.

OPERATING VOLTAGE

OPA237 series op amps operate from single (+2.7V to

+36V) or dual (

±1.35V to ±18V) supplies with excellent

performance. Most behavior remains unchanged through-

out the full operating voltage range. Parameters which

vary significantly with operating voltage are shown in

typical performance curves. Specifications are production

tested with +2.7V, +5V, and

±15V supplies.

OUTPUT CURRENT AND STABILITY

OPA237 series op amps can drive large capacitive loads.

However, under certain limited output conditions any op

amp may become unstable. Figure 1 shows the region

where the OPA237 has a potential for instability. These

load conditions are rarely encountered, especially for single

supply applications. For example, take the case when a

+5V supply with a 10k

Ω load to V

series op amps remain stable with capacitive loads up to

4,000pF, if sinking current and up to 10,000pF, if sourcing

current. Furthermore, in single supply applications where

the load is connected to ground, the op amp is only

sourcing current, and as shown in Figure 1, can drive

10,000pF with output currents up to 1.5mA.

FIGURE 1. Stability-Capacitive Load vs Output Current.

FIGURE 2. Low and High-Side Battery Current Sensing.

R

L

10

Ω

A1

OPA237

+

R

1

38.3k

Ω

R

3

38.3k

Ω

R

5

383k

Ω

R

6

10k

Ω

R

7

9.09k

Ω

R

4

20k

Ω

R

2

19.1k

Ω

A2

OPA237

R

8

100k

Ω

R

H

10

Ω

I

H

V+

V–

V+

V–

2.7V to ±15V

V+ for A

–In

+In

–In

+In

V

To Load

To Load

V

Common-mode range of A2

extends to V– for low-side sensing.

Optional for I

(R

R

common-mode input to A1.

Low-Side

Current Sense

High-Side

Current Sense

Out

Out

NOTE: Low and high-side sensing circuits can be used independently.

V– for A

I

L

2

0.5

1

1.5

Output Current (mA)

–2

–1.5

–1

–0.5

0

100k

10k

1k

100

10

V

V

OPERATION NOT

RECOMMENDED