Analog Devices Inc. LT6557IGN#TRPBF

Overview

LT6557IGN#TRPBF from Analog Devices (formerly Linear Technology) is a high-speed triple video amplifier with fixed gain of 2, programmable DC input bias control, and independent per-channel power/ground pins. It delivers 500MHz small-signal bandwidth, 2200V/µs slew rate, ±100mA output drive, and rail-to-rail output swing within 0.8V of supply rails - enabling full NTSC/PAL video swing on a single 5V supply for RGB HD video driver applications.

For engineers reviewing the LT6557IGN#TRPBF datasheet, LT6557IGN#TRPBF pinout, LT6557IGN#TRPBF application, or LT6557IGN#TRPBF equivalent, key selection criteria include AC-coupled input bias programmability via BCV pin, channel isolation via separate V+/GND pins, differential gain/phase performance (0.02%/0.05°), enable/shutdown functionality, and compatibility with 16-lead SSOP layout and thermal constraints (θJA = 110°C/W).

Technical Context

The LT6557IGN#TRPBF integrates three identical current-feedback amplifiers sharing a common programmable input bias circuit (via BCV pin) and individual enable-controlled shutdown paths. Each channel features independent V+ and GND pins to minimize inter-channel crosstalk (<–80dB at 10MHz) and optimize power supply rejection (42dB typical).

Its architecture supports both AC-coupled operation (with resistor-programmed input bias voltage) and DC-coupled configurations (BCV pin open), while maintaining 0.1dB gain flatness up to 120MHz and full-power bandwidth of 350MHz at 2VP-P output. The internal fixed-gain topology eliminates external feedback resistors and ensures ±0.5% gain error and ±0.4% channel-to-channel gain match.

Key Specifications

Pinout & Package

LT6557IGN#TRPBF is housed in a 16-lead narrow-body SSOP (GN package) with exposed pad not present; thermal resistance θJA = 110°C/W. Pin 17 does not exist in SSOP - only DFN variant includes exposed pad (Pin 17 = GND).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple video amplifier applications.

Compared with LT6558CS8#TRPPBF and LT6553CGN#TRPBF, the LT6557IGN#TRPBF uniquely combines fixed gain-of-2, BCV-programmable input bias, and 500MHz bandwidth in a thermally robust SSOP package - making it optimal for cost-sensitive, space-constrained RGB amplification where external components must be minimized.

Availability

LT6557IGN#TRPBF is available at Aetrix Electronics and suitable for RGB HD video amplifiers, coaxial cable drivers, and low-voltage ADC front-ends requiring stable component supply, consistent parametric performance across production lots, and long-term lifecycle support.

Supply support for LT6557IGN#TRPBF 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 acquired Linear Technology in 2017 and maintains its precision analog portfolio, including high-speed video amplifiers designed for broadcast, medical, and industrial imaging systems.

The LT6557IGN#TRPBF belongs to Linear's legacy high-speed video amplifier product line, engineered specifically for single-supply RGB video signal conditioning with emphasis on differential fidelity, channel isolation, and layout simplicity.

FAQ

What is the operating temperature range for the LT6557IGN#TRPBF?

The LT6557IGN#TRPBF is specified for operation from –40°C to +85°C and is fully tested across this range. Its SSOP package has a maximum junction temperature of 150°C, with thermal resistance θJA = 110°C/W. At 25°C ambient and 5V supply, total quiescent current is ~75mA, resulting in ~375mW dissipation - requiring adequate PCB copper area for heat spreading. The "I" grade designation in LT6557IGN#TRPBF confirms industrial-temperature qualification.

How does the BCV pin function in the LT6557IGN#TRPBF?

The BCV (Bias Control Voltage) pin (Pin 16) on the LT6557IGN#TRPBF allows a single resistor between BCV and GND (Pin 2) to program a common DC bias voltage for all three amplifier inputs - simplifying AC-coupled RGB video designs. With a 348Ω resistor, the input bias is typically 1.25V; opening BCV disables internal biasing, yielding ~200kΩ input impedance for DC-coupled use. This feature eliminates three external bias networks while preserving channel matching.

Can the LT6557IGN#TRPBF drive 75Ω coaxial cables directly?

Yes, the LT6557IGN#TRPBF is explicitly characterized to drive 75Ω loads and is widely used in coaxial cable applications. Each output delivers ±100mA peak current and sustains 2VP-P signals with <0.02% differential gain error. For optimal performance, terminate the far end of the cable and place series 33Ω resistors near the LT6557IGN#TRPBF outputs to damp reflections - a configuration validated in Linear's typical application circuits (e.g., Figure 1 in 6557fa datasheet).

What is the purpose of separate V+ and GND pins for each channel in the LT6557IGN#TRPBF?

The LT6557IGN#TRPBF uses separate V+ R/G/B and GND R/G/B pins to isolate power paths between amplifier channels - preventing shared-impedance coupling that degrades crosstalk. This architecture achieves –80dB hostile crosstalk at 10MHz, critical for RGB video where leakage between color channels causes visible color bleeding. Each V+ pin must be bypassed locally with 10nF + 2.2µF capacitors, and each GND pin tied to a low-inductance ground plane region.

Does the LT6557IGN#TRPBF support dual-supply operation?

Yes, the LT6557IGN#TRPBF supports split supplies: connect all GND pins to the negative rail (e.g., –2.5V) and all V+ pins to the positive rail (e.g., +2.5V). Signal references shift accordingly - inputs and outputs become centered around the negative rail. In this mode, the LT6557IGN#TRPBF retains its 2200V/µs slew rate and 500MHz bandwidth, but the BCV bias circuit requires adjustment since its reference is now the negative rail, not ground.