OPA237_07 Datasheet, PDF (10/19 Pages) Burr-Brown (TI) – SINGLE-SUPPLY OPERATIONAL AMPLIFIERS MicroAmplifier™ Series

OPA237
OPA2237
OPA4237
SBOS057A − OCTOBER 1996 − REVISED FEBRUARY 2007
APPLICATION 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
capacitors.
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
throughout 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.
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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 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
R₈
100kΩ
R₄
20kΩ
R₂ V−
19.1kΩ
R₂ and R₄ divide down the
common−mode input to A1.
V− for A₁, A₂
V+
−In
A2
Out
+In ^OPA237
V_O = 10 • I_L • R_L
R₆
10kΩ
R_L
10Ω
R₇ V^−
9.09kΩ
Low−Side
Current Sense
Optional for I_B Cancellation
(R₇ = R₆ II R₈)
Common−mode range of A2
extends to V− for low−side sensing
To Load
I_L
NOTE: Low and high−side sensing circuits can be used independently.
Figure 2. Low and High-Side Battery Current Sensing
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