OPA369 Datasheet, PDF (9/19 Pages) Burr-Brown (TI) – 1.8V, 1μA max, Zerø-Crossover RAIL-TO-RAIL I/O OPERATIONAL AMPLIFIER

OPA369
OPA2369
www.ti.com ............................................................................................................................................ SBOS414B – AUGUST 2007 – REVISED DECEMBER 2008
APPLICATION INFORMATION
The OPA369 family of operational amplifiers
minimizes power consumption and operates on
supply voltages as low as 1.8V. Power-supply
rejection ratio (PSRR), common-mode rejection ratio
(CMRR), and open-loop gain (A_OL) typical values are
in the range of 100dB or better.
When designing for ultralow power, choose system
components carefully. To minimize current
consumption, select large-value resistors. Any
resistors will react with stray capacitance in the circuit
and the input capacitance of the operational amplifier.
These parasitic RC combinations can affect the
stability of the overall system. A feedback capacitor
may be required to assure stability and limit
overshoot or gain peaking.
Good layout practice mandates the use of a 0.1µF
bypass capacitor placed closely across the supply
pins.
OPERATING VOLTAGE
OPA369 series op amps are fully specified and tested
from +1.8V to +5.5V (±0.9V to ±2.75V). Parameters
that vary significantly with supply voltage are shown
in the Typical Characteristic curves.
INPUT COMMON-MODE VOLTAGE RANGE
The OPA369 family is designed to eliminate the input
offset transition region typically present in most
rail-to-rail complementary stage operational
amplifiers, which allows the OPA369 family of
amplifiers to provide superior common-mode
performance over the entire input range.
The input common-mode voltage range of the
OPA369 family typically extends to each supply rail.
CMRR is specified from the negative rail to the
positive rail. See Figure 4, Normalized Offset Voltage
vs Common-Mode Voltage.
PROTECTING INPUTS FROM
OVER-VOLTAGE
Input currents are typically 10pA. However, large
inputs (greater than 500mV beyond the supply rails)
can cause excessive current to flow in or out of the
input pins. Therefore, in addition to keeping the input
voltage between the supply rails, it is also important
to limit the input current to less than 10mA. This
limiting is easily accomplished with an input resistor,
as shown in Figure 24.
Current-limiting resistor
required if input voltage
exceeds supply rails by
³ 0.5V.
I_OVERLOAD
10mA max
V_IN
5kW
V_S
OPA369
V_OUT
Figure 24. Input Current Protection for Voltages
Exceeding the Supply Voltage
Copyright © 2007–2008, Texas Instruments Incorporated
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Product Folder Link(s): OPA369 OPA2369