LTC6421IUDC-20#TRPBF

Overview

The LTC6421IUDC-20#TRPBF is a dual high-speed differential amplifier and ADC driver from Analog Devices. It features a fixed gain of 20dB (10V/V) with a 1.3GHz -3dB bandwidth, designed for processing signals from DC to 140MHz. The device operates on a single supply voltage ranging from 2.85V to 3.5V, consuming 40mA per amplifier. It provides rail-to-rail output swing, adjustable output common mode voltage between 1V and 1.6V, and low noise characteristics including a 6.2dB noise figure at 100MHz.

Feature Summary

• Dual matched amplifiers with precise channel-to-channel gain matching of ±0.1dB and phase matching of ±0.2° at 100MHz.
• Integrated output common mode biasing allows direct driving of ADCs without external transformers or AC-coupling capacitors.
• Low distortion performance with an equivalent OIP3 of 42dBm and IMD3 of –76dBc at 100MHz.
• Compact 20-lead QFN package design that reduces space and power consumption compared to discrete solutions.

Applications

• Differential ADC Driver
• Single Ended to Differential Conversion
• IF Sampling (Diversity) Receivers
• Broadband I/Q Amplifiers
• Satellite Communications

Procurement Notes

Verify the specific ordering suffix #TRPBF indicates tape and reel packaging when sourcing components. Confirm the 'I' grade designation corresponds to the specified industrial temperature range of –40°C to 85°C. Ensure compatibility with the 20-lead 3mm × 4mm QFN footprint during PCB layout planning. Cross-reference the manufacturer's latest documentation for any updates regarding lead-free finish specifications.

Selection Notes

Select this component for applications requiring a fixed 20dB gain and high linearity in a compact form factor. Consider the 200Ω differential input impedance when designing source matching networks. Evaluate the 40mA supply current against system power budgets. Verify that the 1.3GHz bandwidth meets the signal frequency requirements. Check if the adjustable VOCM range aligns with the target ADC input common mode requirements.

Part Context

This part belongs to the LTC6421 family of dual matched differential amplifiers. It shares the same package and pinout as the LTC6420-20 but offers optimized power characteristics. The device is distinct from single-channel variants like the LTC6401-20. It serves as a specialized solution for broadband signal conditioning before analog-to-digital conversion stages.

Replacement Considerations

LTC6420IUDC-20#TRPBF

FAQ

How is the output common mode voltage controlled?

The output common mode voltage is set by the VOCMA and VOCMB pins, which allow adjustment within a range of 1V to 1.6V.

What is the differential input impedance?

The differential input impedance is nominally 200Ω.

Can the device operate with AC-coupled inputs?

Yes, the inputs can be AC-coupled, in which case the input common mode voltage is automatically biased close to VOCM.