Analog Devices Inc. LTC6430BIUF-20#PBF

Overview

LTC6430BIUF-20#PBF from Analog Devices (formerly Linear Technology) is a high-linearity, fixed-gain differential RF/IF amplifier optimized as an ADC driver for 16-bit+ systems up to 1000MHz. It delivers 20.8dB gain, 51.0dBm OIP3 at 240MHz into 100Ω differential load, 2.9dB noise figure, and >2.75VP-P linear output swing from a single 5V supply consuming 850mW.

For engineers reviewing the LTC6430BIUF-20#PBF datasheet, LTC6430BIUF-20#PBF pinout, LTC6430BIUF-20#PBF application, or LTC6430BIUF-20#PBF equivalent, key selection criteria include differential 100Ω input/output impedance matching, guaranteed B-grade OIP3 performance across 20–1000MHz, thermal stability via exposed-pad QFN, and compatibility with 50Ω test equipment using 1:2 baluns.

Technical Context

The LTC6430BIUF-20#PBF implements a SiGe BiCMOS-based differential gain block with internal bias and temperature compensation, enabling stable linearity over –40°C to 85°C without external tuning. Its core architecture uses shunt-series feedback to simultaneously match 100Ω differential source/load impedances while minimizing Miller effect and ensuring unconditional stability above 20MHz.

It operates as a true differential pair-no DC coupling-requiring external DC-blocking capacitors on +IN/–IN and RF chokes on +OUT/–OUT for bias feed. The device is de-embedded to package pins for S-parameter accuracy, with large-signal metrics (OIP3, P1dB, HD2/HD3) measured directly from Test Circuit A using 50Ω SMA interfaces.

Key Specifications

Pinout & Package

The LTC6430BIUF-20#PBF is housed in a 4mm × 4mm, 24-lead plastic QFN package with exposed thermal pad (Pin 25 = GND). All ground pins (8, 14, 17, 23, 25) must connect to PCB ground plane via multiple vias for low-inductance RF grounding and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar differential RF amplifier applications.

Compared with LMH5401IRHA and ADL5565ACPZ, the LTC6430BIUF-20#PBF offers unique value in plug-and-play 100Ω differential matching, guaranteed B-grade linearity across 20–1000MHz, and thermal robustness via exposed-pad QFN-making it optimal for production CATV, LTE, and high-resolution ADC driver applications where layout simplicity and repeatability are prioritized over maximum bandwidth or minimum noise.

Availability

LTC6430BIUF-20#PBF is available at Aetrix Electronics and suitable for 700–800MHz LTE infrastructure, 40–1000MHz CATV signal distribution, and high-speed differential ADC driver applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LTC6430BIUF-20#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and RF ICs, formed through the acquisition of Linear Technology in 2017.

The LTC6430 family was developed by Linear Technology specifically for wideband, high-linearity differential signal chain amplification - targeting ADC drivers, IF amplifiers, and CATV/LTE infrastructure where 100Ω differential impedance matching and thermal stability are critical.

FAQ

What is the guaranteed OIP3 performance for LTC6430BIUF-20#PBF?

The LTC6430BIUF-20#PBF is the B-grade variant and is not 100% OIP3 tested at 380MHz like the A-grade (LTC6430AIUF-20#PBF). Its typical OIP3 is 47.0dBm at 240MHz and 43.7dBm at 1000MHz, with no minimum guaranteed specification. Designers must verify linearity margins per application using bench characterization or worst-case simulation.

Can LTC6430BIUF-20#PBF operate with a 3.3V supply?

No. The LTC6430BIUF-20#PBF is specified only for 4.75V to 5.25V operation. Its internal bias circuitry, SiGe BiCMOS topology, and 850mW power consumption are optimized for 5V. Operation below 4.75V may cause gain compression, degraded OIP3, or failure to meet AC specifications - use only within the absolute maximum rating of 5.5V and recommended 5.0V ±2.5% range.

How should the exposed thermal pad (Pin 25) of LTC6430BIUF-20#PBF be connected?

The exposed pad (Pin 25) of LTC6430BIUF-20#PBF must be soldered directly to the PCB ground plane using ≥9 thermal vias (0.3mm diameter) arranged in a 3×3 grid under the pad, connected to inner ground layers. This achieves θJC = 40°C/W and ensures both low-inductance RF grounding and effective thermal dissipation - floating or insufficient via count causes gain droop, instability, and accelerated junction temperature rise.

Is LTC6430BIUF-20#PBF compatible with DC-coupled signal paths?

No. The LTC6430BIUF-20#PBF is AC-coupled only: +IN and –IN have internal 1.8V DC bias, while +OUT and –OUT require RF chokes to VCC for bias feed. Its lower frequency cutoff is limited by on-chip matching elements (~20MHz), and DC coupling is impractical due to mismatched input common-mode (1.8V) and output open-collector bias levels - always use DC-blocking capacitors on inputs and chokes on outputs.

What balun ratio is required for 50Ω single-ended test equipment interfacing with LTC6430BIUF-20#PBF?

A 1:2 balun is required on both input and output to interface the LTC6430BIUF-20#PBF's native 100Ω differential ports with standard 50Ω single-ended test equipment. Recommended models include Mini-Circuits ADT2-IT (50–300MHz), ADT2-1P (300–400MHz), and ADTL2-18 (400–1000MHz), all using CD542 footprint - this transformation preserves impedance match, gain accuracy, and OIP3 measurement integrity.