SLOS712I – JANUARY 2011 – REVISED OCTOBER 2016
10 Power Supply Recommendations
The OPAx836 devices are intended to work in a supply range of 2.7 V to 5 V. Supply-voltage tolerances are
supported with the specified operating range of 2.5 V (7% on a 2.7-V supply) and 5.5 V (10% on a 5-V supply).
Good power-supply bypassing is required. Minimize the distance (< 0.1 inch) from the power-supply pins to high
frequency, 0.1-μF decoupling capacitors. A larger capacitor (2.2 µF is typical) is used along with a high
frequency, 0.1-µF supply decoupling capacitor at the device supply pins. For single-supply operation, only the
positive supply has these capacitors. When a split supply is used, use these capacitors for each supply to
ground. If necessary, place the larger capacitors farther from the device and share these capacitors among
several devices in the same area of the PCB. Avoid narrow power and ground traces to minimize inductance
between the pins and the decoupling capacitors. An optional supply decoupling capacitor across the two power
supplies (for bipolar operation) reduces second harmonic distortion.
11.1 Layout Guidelines
The OPA835DBV, OPA836DBV EVM (SLOU314) can be used as a reference when designing the circuit board.
TI recommends following the EVM layout of the external components near the amplifier, ground-plane
construction, and power routing. General guidelines are listed as follows:
1. Signal routing must be direct and as short as possible into and out of the operational amplifier.
2. The feedback path must be short and direct avoiding vias if possible especially with G = +1.
3. Ground or power planes must be removed from directly under the negative input and output pins of the
4. TI recommends placing a series output resistor as close to the output pin as possible. See Series Output
Resistor vs Capacitive Load (Figure 17) for recommended values for the expected capacitive load.
5. A 2.2-µF power-supply decoupling capacitor must be placed within two inches of the device and can be
shared with other operational amplifiers. For spit supply, a capacitor is required for both supplies.
6. A 0.1-µF power-supply decoupling capacitor must be placed as close to the power supply pins as possible,
preferably within 0.1 inch. For split supply, a capacitor is required for both supplies.
7. The PD pin uses TTL logic levels. If the pin is not used, it must be tied to the positive supply to enable the
amplifier. If the pin is used, it must be actively driven. A bypass capacitor is not necessary, but is used for
robustness in noisy environments.
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Product Folder Links: OPA836 OPA2836
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