OPA4317 Datasheet, PDF (9/30 Pages) Texas Instruments – Low-Offset, Rail-to-Rail I/O Operational Amplifier

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APPLICATIONS INFORMATION
OPA317
OPA2317
OPA4317
SBOS682A – MAY 2013 – REVISED JUNE 2013
The OPA317, OPA2317, and OPA4317 are unity-gain stable, precision operational amplifiers free from
unexpected output and phase reversal. Proprietary Zerø-Drift circuitry gives the benefit of low input offset voltage
over time and temperature, as well as lowering the 1/f noise component. As a result of the high PSRR, these
devices work well in applications that run directly from battery power without regulation. The OPA317 family is
optimized for low-voltage, single-supply operation. These miniature, high-precision, low quiescent current
amplifiers offer high-impedance inputs that have a common-mode range 100 mV beyond the supplies, and a rail-
to-rail output that swings within 100 mV of the supplies under normal test conditions. The OPA317 series are
precision amplifiers for cost-sensitive applications.
OPERATING VOLTAGE
The OPA317 series op amps can be used with single or dual supplies from an operating range of V_S = +1.8 V
(±0.9 V) up to +5.5 V (±2.75 V).
CAUTION
Supply voltages greater than +7 V can permanently damage the device.
See the Absolute Maximum Ratings table. Key parameters that vary over the supply voltage or temperature
range are shown in the Typical Characteristics section of this data sheet.
INPUT VOLTAGE
The OPA317, OPA2317, and OPA4317 input common-mode voltage range extends 0.1 V beyond the supply
rails. The OPA317 is designed to cover the full range without the troublesome transition region found in some
other rail-to-rail amplifiers.
Typically, input bias current is about 200 pA; however, input voltages exceeding the power supplies can cause
excessive current to flow into or out of the input pins. Momentary voltages greater than the power supply can be
tolerated if the input current is limited to 10 mA. This limitation is easily accomplished with an input resistor, as
shown in Figure 18.
Current-limiting resistor
required if input voltage
exceeds supply rails by
³ 0.3 V.
I_OVERLOAD
10 mA max
V_IN
5 kW
+5 V
Device
V_OUT
Figure 18. Input Current Protection
INPUT DIFFERENTIAL VOLTAGE
The typical input bias current of the OPA317 during normal operation is approximately 200 pA. In overdriven
conditions, the bias current can increase significantly (see Figure 17).The most common cause of an overdriven
condition occurs when the op amp is outside of the linear range of operation. When the output of the op amp is
driven to one of the supply rails, the feedback loop requirements cannot be satisfied and a differential input
voltage develops across the input pins. This differential input voltage results in activation of parasitic diodes
inside the front-end input chopping switches that combine with 10-kΩ electromagnetic interference (EMI) filter
resistors to create the equivalent circuit shown in Figure 19. Note that the input bias current remains within
specification within the linear region.
Copyright © 2013, Texas Instruments Incorporated
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Product Folder Links: OPA317 OPA2317 OPA4317