AD8324JRQ

Overview

The AD8324JRQ is a low-cost, single-channel cable line driver designed for coaxial transmission. It operates from a 3.13 V to 3.47 V supply with a typical quiescent current of 207 mA at maximum gain. The device provides a voltage gain range of 59 dB, adjustable in 1 dB steps via an SPI interface. Key electrical specifications include a bandwidth of 100 MHz, an output noise level of 1.3 nV/√Hz at minimum gain, and a differential output impedance of 75 Ω.

Feature Summary

• Digitally programmable gain over a 59 dB range using an 8-bit serial word
• Maintains 75 Ω differential output impedance during transmit enable and disable states
• Supports DOCSIS 2.0 and EuroDOCSIS reverse path transmission standards
• Includes sleep mode reducing supply current to approximately 30 μA

Applications

• DOCSIS 2.0 and EuroDOCSIS cable modems
• CATV set-top boxes
• CATV telephony modems
• Coaxial and twisted pair line drivers

Procurement Notes

Verify the specific package variant, as the AD8324 family includes both 20-lead LFCSP and 20-lead QSOP options. Confirm that the ordering suffix corresponds to the required thermal and temperature performance characteristics. Ensure compatibility with the system's SPI interface timing requirements for SDATA, CLK, and DATEN signals.

Selection Notes

Select this component for upstream power amplifier applications requiring precise digital gain control. The device is optimized for driving 75 Ω loads through a 1:1 transformer. Consider the thermal resistance of the chosen package when designing the PCB layout, particularly regarding the exposed pad connection for the LFCSP variant or the lead dissipation for the QSOP variant.

Part Context

The AD8324 is part of Analog Devices' specialized amplifier portfolio focused on cable television infrastructure. It serves as a cost-effective solution for DOCSIS-compliant systems, replacing discrete amplifier designs with a fully integrated, digitally controlled driver. The device simplifies board layout by integrating the attenuator core and logic interfaces.

Replacement Considerations

Public documentation confirms pin-compatible alternatives within the AD8324 family, such as the AD8324ACP and AD8324ACPZ. These variants share identical functional descriptions but may differ in package type (LFCSP vs. QSOP) or reel packaging. Verify that any substitute maintains the same operating temperature range and electrical specifications.