OPA237 Datasheet, PDF (10/12 Pages) Burr-Brown (TI) – SINGLE-SUPPLY OPERATIONAL AMPLIFIERS MicroAmplifier ™ Series

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 10kΩ load to V_S/2 is used. OPA237
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.
100k
10k
OPERATION NOT
RECOMMENDED
1k
V_S = +5V, ±15V
100
V_S = +2.7V
10
–2 –1.5 –1 –0.5 0
0.5 1
Output Current (mA)
1.5 2
FIGURE 1. Stability-Capacitive Load vs Output Current.
R_H
10Ω
I_H
R₁
38.3kΩ
R₃
38.3kΩ
High-Side
Current Sense
R₅
383kΩ
V+
–In
A1
Out
+In ^OPA237
To Load
V_O = 10 • I_H • R_H
V+ for A₁, A₂
+
2.7V to ±15V
V– for A₁, A₂
R₆
10kΩ
R_L
10Ω
I_L
R₈
100kΩ
R₄
20kΩ
V–
R₂
19.1kΩ
R₂ and R₄ divide down the
common-mode input to A1.
V+
–In
A2
Out
+In ^OPA237
R₇ V–
9.09kΩ
Low-Side
Current Sense
Optional for I_B Cancellation
(R₇ = R₆ II R₈)
V_O = 10 • I_L • R_L
Common-mode range of A2
extends to V– for low-side sensing.
To Load
NOTE: Low and high-side sensing circuits can be used independently.
FIGURE 2. Low and High-Side Battery Current Sensing.
®
OPA237, 2237, 4237
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