LT1993IUD-4#PBF

Overview

The LT1993IUD-4#PBF is a low distortion, low noise differential amplifier and ADC driver designed for applications from DC to 900MHz. It features a fixed gain of 4V/V (12dB) and operates on a single 5V supply with typical current consumption of 100mA. The device includes built-in 175MHz differential lowpass filtering and adjustable output common mode voltage via the VOCM pin. It is housed in a compact 16-lead 3mm x 3mm QFN package and supports an operating temperature range of -40°C to 85°C.

Feature Summary

• Integrated 175MHz differential lowpass filter providing additional filtered outputs to reduce external component count.
• Adjustable output common mode voltage eliminates the need for output transformers or AC-coupling capacitors.
• Capable of single-ended to differential conversion and differential to single-ended conversion with minimal support circuitry.
• Low input-referred noise and high linearity make it suitable for driving high-speed 12-bit and 14-bit ADCs.

Applications

• Differential ADC driver for imaging and communications systems
• IF sampling receivers and SAW filter interfacing/buffering
• General-purpose differential gain block requiring differential drive
• Data acquisition systems functioning at frequencies down to DC

Procurement Notes

Verify the specific suffix 'I' indicates the industrial temperature grade (-40°C to 85°C), as opposed to the commercial grade. Confirm the '#PBF' designation ensures lead-free compliance. Ensure the UD package marking matches the 16-lead QFN physical dimensions. Cross-reference the datasheet revision date to confirm electrical characteristics have not changed.

Selection Notes

Select this part when a fixed 4V/V gain is required alongside integrated filtering to simplify PCB layout. The adjustable VOCM pin allows direct coupling to ADCs without level shifting components. Consider the 100mA supply current against system power budgets. Evaluate the 900MHz bandwidth against the Nyquist frequency of the target ADC sampling rate.

Part Context

This component belongs to the LT1993 family of differential amplifiers. The LT1993CUD-4 is the commercial grade variant, while the LT1993IUD-4 extends the guaranteed performance to the full industrial temperature range. The device serves as a specialized interface solution between analog front-ends and high-speed digital converters.

Replacement Considerations

LT1993CUD-4#PBF: Commercial grade equivalent with identical electrical specifications but limited to 0°C to 70°C operation.

FAQ

How does the internal filtering affect the unfiltered outputs?

The internal 175MHz lowpass filter is implemented on separate pins (+OUTFILTERED and –OUTFILTERED). The primary unfiltered outputs (+OUT and –OUT) remain unaffected by the filter network and provide the full 900MHz bandwidth.

Can the LT1993IUD-4 operate with split supplies?

Yes, split supplies are possible provided the total voltage difference between VCC and VEE remains 5V. The exposed pad must be tied to VEEC, and if split supplies are used, it should not be tied to ground.