8.3.4 Slew Rate and Output Stage

In addition to wide bandwidth, the OPA855-Q1 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-Q1 implies that the device accurately

reproduces a 2-V, sub-ns pulse edge, as seen in Figure 6-20. The wide bandwidth and slew rate of the

OPA855-Q1 make it an excellent amplifier for high-speed signal-chain front ends.

Figure 8-7 shows the open-loop output impedance of the OPA855-Q1 as a function of frequency. To achieve

high slew rates and low output impedance across frequency, the output swing of the OPA855-Q1 is limited

to approximately 3 V. The OPA855-Q1 is typically used in conjunction with high-speed pipeline ADCs and

flash ADCs that have limited input ranges. Therefore, the OPA855-Q1 output swing range coupled with the

class-leading voltage noise specification maximizes the overall dynamic range of the signal chain.

Frequency (Hz)

0

2

4

6

8

10

12

14

16

18

20

10k

100k

1M

10M

100M

1G

10G

D601

www.ti.com

OPA855-Q1

SBOSA57A – FEBRUARY 2021 – REVISED MARCH 2021

Copyright © 2021 Texas Instruments Incorporated

Submit Document Feedback

19

Product Folder Links: OPA855-Q1