OPA4314AIPWR Datasheet, PDF (14/36 Pages) Texas Instruments – 3-MHz, Low-Power, Low-Noise, RRIO, 1.8-V CMOS Operational Amplifier

OPA314
OPA2314
OPA4314
SBOS563F – MAY 2011 – REVISED AUGUST 2013
www.ti.com
APPLICATION INFORMATION
The OPA314 is a family of low-power, rail-to-rail input and output operational amplifiers specifically designed for
portable applications. These devices operate from 1.8 V to 5.5 V, are unity-gain stable, and suitable for a wide
range of general-purpose applications. The class AB output stage is capable of driving ≤ 10-kΩ loads connected
to any point between V+ and ground. The input common-mode voltage range includes both rails, and allows the
OPA314 series to be used in virtually any single-supply application. Rail-to-rail input and output swing
significantly increases dynamic range, especially in low-supply applications, and makes them ideal for driving
sampling analog-to-digital converters (ADCs).
The OPA314 features 3-MHz bandwidth and 1.5-V/μs slew rate with only 150-μA supply current per channel,
providing good ac performance at very low power consumption. DC applications are also well served with a very
low input noise voltage of 14 nV/√Hz at 1 kHz, low input bias current (0.2 pA), and an input offset voltage of
0.5 mV (typical).
OPERATING VOLTAGE
The OPA314 series op amps are fully specified and ensured for operation from +1.8 V to +5.5 V. In addition,
many specifications apply from –40°C to +125°C. Parameters that vary significantly with operating voltages or
temperature are shown in the Typical Characteristics graphs. Power-supply pins should be bypassed with 0.01-
μF ceramic capacitors.
RAIL-TO-RAIL INPUT
The input common-mode voltage range of the OPA314 series extends 200 mV beyond the supply rails. This
performance is achieved with a complementary input stage: an N-channel input differential pair in parallel with a
P-channel differential pair, as shown in Figure 33. The N-channel pair is active for input voltages close to the
positive rail, typically (V+) – 1.3 V to 200 mV above the positive supply, while the P-channel pair is on for inputs
from 200 mV below the negative supply to approximately (V+) – 1.3 V. There is a small transition region, typically
(V+) – 1.4 V to (V+) – 1.2 V, in which both pairs are on. This 200-mV transition region can vary up to 300 mV
with process variation. Thus, the transition region (both stages on) can range from (V+) – 1.7 V to (V+) – 1.5 V
on the low end, up to (V+) – 1.1 V to (V+) – 0.9 V on the high end. Within this transition region, PSRR, CMRR,
offset voltage, offset drift, and THD may be degraded compared to device operation outside this region.
V+
Reference
Current
V_IN+
V_IN-
V_BIAS1
Class AB
Control
V_O
Circuitry
V_BIAS2
V-
(Ground)
Figure 33. Simplified Schematic
14
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