OPA818 2.7GHz, High-Voltage, FET-Input, Low-Noise, Operational Amplifier

1 Features

• High speed:

– Gain-bandwidth product (GBWP): 2.7GHz

– Bandwidth (G = 7V/V): 765MHz

– Large-signal bandwidth (2VPP): 400MHz

– Slew rate: 1400V/µs

• Decompensated gain: 7V/V stable

• Low noise:

– Input voltage noise: 2.2nV/√Hz

– Input current noise: 3fA/√Hz (f = 10kHz)

• Input bias current: 4pA (typical)

• Low input capacitance:

– Common-mode: 1.9pF

– Differential mode: 0.5pF

• Low distortion (G = 7V/V, RL = 1kΩ, VO = 2VPP):

– HD2, HD3 at 1MHz: –104dBc, –108dBc

– HD2, HD3 at 50MHz: –57dBc, –72dBc

• Wide supply range: 6V to 13V

• Output swing: 8VPP (VS = 10V)

• Supply current: 27.7mA

• Shutdown supply current: 27µA

• Performance upgrade to OPA657

2 Applications

• Wideband transimpedance amplifier (TIA)

• Wafer scanning equipment

• Optical communication module

• High-speed data acquisition (DAQ)

• Active probe

• Optical time-domain reflectometry (OTDR)

• Test and measurement front-end

• Medical and chemical analyzer

3 Description

The OPA818 is a decompensated, voltage-feedback

operational amplifier for high-speed and wide-

dynamic-range applications. The OPA818 has a

low-noise JFET input stage that combines high

gain-bandwidth with a wide supply range from 6V

to 13V. The fast slew rate (1400V/µs) provides

high, large-signal bandwidth and low distortion. This

amplifier is manufactured using TI's proprietary, high-

speed, silicon-germanium (SiGe) process to achieve

significant performance improvements over other

high-speed, FET-input amplifiers.

The OPA818 is an extremely versatile, wideband

TIA photodiode amp for use in optical test and

communication

equipment,

and

many

medical,

scientific, and industrial instruments. The OPA818

showcases a 2.7GHz GBWP, low 2.4pF total input

capacitance, and 2.2nV/√Hz input noise. The OPA818

achieves over 85MHz signal bandwidth in a TIA

configuration with 20kΩ TIA gain (RF) and 0.5pF

photodiode capacitance (CD) with wide output swings.

The low-noise architecture with picoampere of input

bias current is also an excellent choice for test and

measurement applications. Though typically stable in

gains ≥ 7V/V, the OPA818 is designed for use in

applications with lower gains by applying noise-gain

shaping techniques.

The OPA818 is available in an 5-pin SOT-23 package

and an 8-lead WSON package with an exposed

thermal pad for heat dissipation. This device is

specified for operation over the industrial temperature

range of –40°C to +85°C.

Package Information

PART NUMBER(1)

PACKAGE(2)

PACKAGE SIZE(3)

OPA818

DRG (WSON, 8)

3mm × 3mm

DBV (SOT-23, 5)

2.9mm × 2.8mm

(1)

See Section 4.

(2)

For more information, see Section 11.

(3)

The package size (length × width) is a nominal value and

includes pins, where applicable.

THS4541

V

REF1

V

BIAS

V

REF2

+

–

100k

ADC

C

F

R

G1

R

G2

R

F1

R

F2

+

–

V

CM

+5V

–5V

OPA818

High-Speed Optical Front-End

Photodiode Capacitance, CD (pF)

0

2

4

6

8

10

12

14

16

18

20

5

10

100

RF = 20k

RF = 50k

RF = 100k

RF = 500k

Photodiode Capacitance vs 3dB Bandwidth

OPA818

SBOS940B – MAY 2019 – REVISED DECEMBER 2025

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.