OPA855 datasheet(19/41 Pages) TI2

19 / 41 page

8.3.4 Slew Rate and Output Stage

In addition to wide bandwidth, the OPA855 features a high slew rate of 2750 V/µs. The slew rate is a

critical parameter in high-speed pulse applications with narrow sub-10-ns pulses, such as optical time-domain

reflectometry (OTDR) and LIDAR. The high slew rate of the OPA855 implies that the device accurately

reproduces a 2-V, sub-ns pulse edge; see also Figure 6-20. The wide bandwidth and slew rate make the

OPA855 an excellent amplifier for high-speed signal-chain front ends.

Figure 8-7 shows the open-loop output impedance of the OPA855 as a function of frequency. To achieve

high slew rates and low output impedance across frequency, the output swing of the OPA855 is limited to

approximately 3 V. The OPA855 is typically used in conjunction with high-speed pipeline ADCs and flash ADCs

that have limited input ranges. Therefore, the OPA855 output swing range coupled with the class-leading voltage

noise specification maximizes the overall dynamic range of the signal chain.

Frequency (Hz)

10k

100k

10M

100M

10G

D601

Figure 8-7. Open-Loop Output Impedance (ZOL) vs Frequency

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OPA855

SBOS622D – JULY 2018 – REVISED MAY 2025

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OPA855 Datasheet(PDF) 19 Page - Texas Instruments