LTC6421CUDC-20#TRPBF

Overview

The LTC6421CUDC-20#TRPBF is a dual high-speed differential amplifier and ADC driver designed for processing signals from DC to 140MHz. It features a fixed gain of 20dB (10V/V) and a 1.3GHz -3dB bandwidth. The device operates on a single supply voltage ranging from 2.85V to 3.5V, drawing 40mA per amplifier. Key electrical characteristics include a noise figure of 6.2dB, an equivalent output third-order intercept point (OIP3) of 42dBm at 100MHz, and a slew rate of 4500V/µs. It utilizes a 20-lead 3mm × 4mm QFN package.

Feature Summary

• Dual matched amplifiers with channel-to-channel gain matching of ±0.1dB and phase matching of ±0.2° at 100MHz.
• Adjustable output common mode voltage via external pin, supporting rail-to-rail output swing without requiring transformers or AC-coupling capacitors.
• Differential inputs and outputs with low distortion performance suitable for driving high-resolution analog-to-digital converters.
• Integrated enable pins allow for low-power shutdown mode control.

Applications

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

Procurement Notes

Verify the specific temperature grade suffix 'C' indicates operation from 0°C to 70°C, distinct from the industrial grade 'I'. Confirm the '#TRPBF' suffix denotes tape and reel packaging with lead-free finish. Ensure the component matches the Linear Technology/Analog Devices manufacturing origin as specified in the datasheet documentation.

Selection Notes

Select this component when a fixed 20dB gain is required for broadband signal conditioning. It is optimized for driving 12-, 14-, and 16-bit ADCs directly. Consider the 200Ω differential input impedance for source matching requirements. Evaluate the power consumption against other family members like the LTC6400 series if lowest distortion or different gain levels are needed.

Part Context

This part belongs to the LTC6421-20 family of dual matched 1.3GHz differential amplifiers. It shares architectural similarities with the LTC6420-20 but offers lower power consumption compared to the LTC6400 series. The device is manufactured using advanced silicon-germanium processes to achieve high speed and low noise performance in a compact QFN footprint.

Replacement Considerations

LTC6421IUDC-20#TRPBF: Identical electrical specifications but guaranteed over the –40°C to 85°C temperature range.

FAQ

How is the output common mode voltage controlled?

The output common mode voltage is set by an external pin (VOCM), allowing adjustment between 1V and 1.6V independently of the inputs.

What is the differential input impedance?

The differential input impedance is 200Ω.