OPA1652_16 Datasheet, PDF (24/42 Pages) Texas Instruments – Audio Operational Amplifiers

OPA1652, OPA1654
SBOS477A – DECEMBER 2011 – REVISED AUGUST 2016
www.ti.com
9 Power Supply Recommendations
The OPA165x are specified for operation from 4.5 V to 36 V (±2.25 V to ±18 V); many specifications apply from
–40°C to +85°C. Parameters that can exhibit significant variance with regard to operating voltage or temperature
are presented in the Typical Characteristics section. Applications with noisy or high-impedance power supplies
require decoupling capacitors close to the device pins. In most cases, 0.1-µF capacitors are adequate.
10 Layout
10.1 Layout Guidelines
For best operational performance of the device, use good printed-circuit board (PCB) layout practices, including:
• Noise can propagate into analog circuitry through the power pins of the circuit as a whole and of op amp
itself. Bypass capacitors are used to reduce the coupled noise by providing low-impedance power sources
local to the analog circuitry.
– Connect low-ESR, 0.1-µF ceramic bypass capacitors between each supply pin and ground, placed as
close to the device as possible. A single bypass capacitor from V+ to ground is applicable for single-
supply applications.
• Separate grounding for analog and digital portions of circuitry is one of the simplest and most-effective
methods of noise suppression. One or more layers on multilayer PCBs are usually devoted to ground planes.
A ground plane helps distribute heat and reduces electromagnetic interference (EMI) noise pickup. Physically
separate digital and analog grounds, observing the flow of the ground current.
• To reduce parasitic coupling, run the input traces as far away from the supply or output traces as possible. If
these traces cannot be kept separate, crossing the sensitive trace perpendicular is much better as opposed to
in parallel with the noisy trace.
• Place the external components as close to the device as possible. As illustrated in Figure 47, keeping R_F and
R_G close to the inverting input minimizes parasitic capacitance.
• Keep the length of input traces as short as possible. Always remember that the input traces are the most
sensitive part of the circuit.
• Consider a driven, low-impedance guard ring around the critical traces. A guard ring can significantly reduce
leakage currents from nearby traces that are at different potentials.
• Cleaning the PCB following board assembly is recommended for best performance.
• Any precision integrated circuit can experience performance shifts resulting from moisture ingress into the
plastic package. Following any aqueous PCB cleaning process, baking the PCB assembly is recommended to
remove moisture introduced into the device packaging during the cleaning process. A low temperature, post-
cleaning bake at 85°C for 30 minutes is sufficient for most circumstances.
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