8.3.4 Slew Rate and Output Stage

In addition to wide bandwidth, the OPA856 features a high slew rate of 350 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 OPA856 implies that the device accurately

reproduces a 2-V, sub-ns pulse edge, as seen in Figure 7-18 . The wide bandwidth and slew rate of the OPA856

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

Figure 8-7 shows the open-loop output impedance of the OPA856 as a function of frequency. To achieve high

slew rates and low output impedance across frequency, the output swing of the OPA856 is limited to

approximately 3 V. The OPA856 is typically used in conjunction with high-speed pipeline ADCs and flash ADCs

that have limited input ranges. Therefore, the OPA856 output swing range coupled with the class-leading voltage

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

Frequency (Hz)

0

5

10

15

20

25

30

10k

100k

1M

10M

100M

1G

10G

www.ti.com

OPA856

SBOS623 – OCTOBER 2020

Copyright © 2020 Texas Instruments Incorporated

Submit Document Feedback

17

Product Folder Links: OPA856