AD8128ACPZ-RL

Overview

The AD8128ACPZ-RL is a high-speed differential receiver and equalizer designed to compensate for transmission losses in Category-5 (CAT-5) unshielded twisted pair cables. It achieves an equalized bandwidth of 120 MHz for cable lengths up to 100 meters, with ±1 dB flatness extending to 70 MHz. The device operates on a ±5 V supply with a quiescent current of 24 mA. Key electrical specifications include a slew rate of 2700 V/μs, an integrated output noise of 1.5 mV rms over a 1 GHz bandwidth, and a typical DC offset voltage error of 7 mV.

Feature Summary

• Compensates for CAT-5/CAT-5e cable losses using summed frequency-dependent gain stages
• Features two voltage-controlled pins for independent high-frequency peaking and broadband gain adjustment
• Includes a DC output offset adjust pin for flexibility in DC-coupled systems
• Supports cascading two devices to extend equalization range up to 200 meters

Applications

• Keyboard-video-mouse (KVM) systems
• RGB video transmission over unshielded twisted pair (UTP) cables
• Professional video projection and distribution networks
• Security video surveillance receivers

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm packaging format. The AD8128ACPZ-RL designation indicates a reel package variant within the AD8128 family. Ensure compatibility with the required temperature range and RoHS compliance status as defined in the latest datasheet revision before procurement.

Selection Notes

Select this component for applications requiring low-noise equalization of CAT-5 cables up to 100 meters. The device supports both differential and single-ended inputs. For longer distances exceeding 100 meters, consider cascading multiple units. Ensure the input common-mode voltage remains within the specified ±3.0 V range to prevent signal distortion.

Part Context

The AD8128 belongs to Analog Devices' line of cable equalizers, specifically engineered for video signal integrity over UTP cabling. It serves as a standalone receiver or complements triple differential receivers like the AD8143. The part is housed in a compact 8-lead, 3 mm × 3 mm LFCSP package suitable for space-constrained PCB layouts.

Replacement Considerations

Publicly confirmed substitutes are not identified in the provided documentation. Designers should evaluate other Analog Devices differential receivers based on bandwidth, noise performance, and package compatibility if substitution is required.

FAQ

How is the equalization adjusted for different cable lengths?

Equalization is controlled via two voltage pins: VPEAK adjusts high-frequency peaking (0 V to 1 V) and VGAIN adjusts broadband gain (0 V to 1 V). These voltages are linearly correlated to the cable length.

Can the AD8128 be used for cable lengths longer than 100 meters?

Yes, by cascading two AD8128 devices in series, the system can provide equalization for up to 200 meters of CAT-5 cable, though rise time and settling time may slightly degrade.

What is the purpose of the VOFFSET pin?

The VOFFSET pin allows for DC output offset adjustment within a range of ±2.5 V, providing flexibility for DC-coupled systems and ensuring proper signal levels at the receiver.