Analog Devices Inc. LT1253CS8

Overview

LT1253CS8 from Analog Devices (formerly Linear Technology) is a dual current feedback video amplifier optimized for RGB and composite video signal conditioning. It delivers 90MHz bandwidth at ±5V, 0.03% differential gain error and 0.28° differential phase error into 150Ω loads, enabling high-fidelity analog video transmission in PC-to-workstation interconnects and broadcast-grade video routing systems.

For engineers reviewing the LT1253CS8 datasheet, LT1253CS8 pinout, LT1253CS8 application, or LT1253CS8 equivalent, key selection criteria include its 150°C/W junction-to-ambient thermal resistance in SOIC-8, ±2V to ±14V dual-supply operation, and verified performance in NTSC video cable driving with <0.3% total harmonic distortion at 5MHz.

Technical Context

The LT1253CS8 implements a current feedback architecture with separate high-impedance noninverting inputs and low-impedance inverting inputs, enabling stable gain configurations up to AV = 10 without external compensation. Its output stage delivers 55mA short-circuit current and sustains ±3.7V swing into 150Ω at ±5V supplies.

Thermal design is constrained by θ_JA = 150°C/W in the S8 package, requiring ambient temperature derating when dissipating >0.533W - e.g., at ±10.6V supply with 2V_P-P output into 150Ω. Channel separation exceeds 88dB at 10MHz, confirming isolation between dual amplifiers sharing only V+ and V− rails.

Key Specifications

Pinout & Package

The LT1253CS8 is housed in an 8-lead plastic SOIC (S8) package with industry-standard dual op amp pinout and 1.27mm lead pitch. Thermal pad is not present; PCB copper area under package body must be minimized to maintain specified θ_JA = 150°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH6629MA/NOPB and THS3202D, the LT1253CS8 offers the lowest cost-per-channel solution validated for NTSC/PAL compliance, with proven 0.03%/0.28° performance and SOIC-8 footprint compatibility with legacy designs - making it optimal for cost-sensitive, standards-compliant video equipment where 90MHz bandwidth suffices.

Availability

LT1253CS8 is available at Aetrix Electronics and suitable for RGB video distribution, composite video routing, IF stage gain blocks, and video test equipment output requiring stable component supply across industrial, broadcast, and embedded display applications.

Supply support for LT1253CS8 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 amplifiers for signal integrity-critical applications.

The LT1253CS8 belongs to Linear's legacy video amplifier product line, designed specifically for cost-effective, high-fidelity analog video signal conditioning in consumer, professional, and instrumentation systems.

FAQ

What is the maximum safe operating temperature for the LT1253CS8 in its S8 package?

The LT1253CS8 has a maximum junction temperature (T_JMAX) of 150°C. With θ_JA = 150°C/W, ambient temperature must be limited to ≤59.7°C when dissipating 0.602W (dual-channel worst case). At 70°C ambient, supply voltage must be reduced to ±10.6V to stay within the 0.533W package limit. Derating curves in the datasheet confirm this relationship across temperature and load conditions.

Does the LT1253CS8 support single-supply operation, and what is the minimum recommended supply voltage?

Yes, the LT1253CS8 supports single-supply operation from 4V to 24V (V_CC to GND). The minimum recommended supply is 4V (±2V dual), below which output swing and slew rate degrade significantly. At 4V single supply, common-mode input range extends to within 1.5V of rails, and output can swing to within 1.0V of each rail into 500Ω - sufficient for many CCTV and portable video applications.

How does the LT1253CS8 achieve 94dB channel separation despite sharing power rails?

The LT1253CS8 achieves 94dB channel separation at 5MHz through complete die-level isolation of amplifier cores - only V+ and V− supply pins are shared. Internal substrate and guard ring design prevent signal coupling between channels. This is verified in the datasheet's "Channel Separation" plot, which shows >88dB isolation up to 10MHz, enabling simultaneous RGB driving without visible crosstalk on calibrated monitors.

Can the LT1253CS8 drive 75Ω coaxial cable directly, and what termination is required?

Yes, the LT1253CS8 is explicitly characterized for 75Ω cable driving. It requires source-series termination: a 75Ω resistor placed between the LT1253CS8 output pin and the cable input. This matches the amplifier's low output impedance (~0.1Ω) to the cable characteristic impedance, preventing reflections. The datasheet's Figure TA01 shows this configuration with 620Ω feedback resistors and confirms 1V_P-P output into 75Ω with <5% overshoot.

What is the purpose of the thermal resistance specification TJ = TA + (PD × 150°C/W) for the LT1253CS8?

This formula defines how junction temperature (T_J) rises above ambient (T_A) based on power dissipation (P_D) in the S8 package. For the LT1253CS8, θ_JA = 150°C/W means each watt dissipated raises the die temperature by 150°C relative to ambient air. It is used to calculate maximum allowable ambient temperature for a given load condition - e.g., at 0.533W, T_J reaches 150°C exactly at T_A = 70°C, establishing the absolute thermal operating limit.