Signal Conditioning Operational Amplifiers (Op Amps) Video Functions
Signal Conditioning Operational Amplifiers (Op Amps) Current Feedback Amplifiers

LT1251 - 40MHz Video Fader and DC Gain Controlled Amplifier

Features

  • Accurate Linear Gain Control: ±1% Typ, ±3% Max
  • Constant Gain with Temperature
  • Wide Bandwidth: 40MHz
  • High Slew Rate: 300V/µs
  • Fast Control Path: 10MHz
  • Low Control Feedthrough: 2.5mV
  • High Output Current: 40mA
  • Low Output Noise
    45nV/rtHz at AV = 1
    270nV/rtHz at AV = 100
  • Low Distortion: 0.01%
  • Wide Supply Range: ±2.5V to ±15V
  • Low Supply Current: 13mA
  • Low Differential Gain and Phase: 0.02%, 0.02°

Typical Application

LT1251 Typical Application
LT1251 Typical Application

Description

The LT®1251/LT1256 are 2-input, 1-output, 40MHz current feedback amplifiers with a linear control circuit that sets the amount each input contributes to the output. These parts make excellent electronically controlled variable gain amplifiers, filters, mixers and faders. The only external components required are the power supply bypass capacitors and the feedback resistors. Both parts operate on supplies from ±2.5V (or single 5V) to ±15V (or single 30V). Absolute gain accuracy is trimmed at wafer sort to minimize part-to-part variations. The circuit is completely temperature compensated. The LT1251 includes circuitry that eliminates the need for accurate control signals around zero and full scale. For control signals of less than 2% or greater than 98%, the LT1251 sets one input completely off and the other completely on. This is ideal for fader applications because it eliminates off-channel feedthrough due to offset or gain errors in the control signals. The LT1256 does not have this on/off feature and operates linearly over the complete control range. The LT1256 is recommended for applications requiring more than 20dB of linear control range.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing		 RoHS
LT1251CN#PBF N-14 N C 05-08-1510 (N14) Yes
LT1251CS#PBF SO-14 S C 05-08-1610 (S14) Yes
LT1251CS#TRPBF SO-14 S C 05-08-1610 (S14) Yes


LT1251 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)		 Price
(1k)*		 RoHS
LT1251CN#PBF N-14 C $7.33 $5.85 Yes
LT1251CS#PBF SO-14 C $7.75 $6.10 Yes
LT1251CS#TRPBF SO-14 C $6.16 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Composite Video Gain Control
  • RGB, YUV Video Gain Control
  • Video Faders, Keyers
  • Gamma Correction Amplifiers
  • Audio Gain Control, Faders
  • Multipliers, Modulators
  • Electronically Tunable Filters

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Design Tools

LTspice

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Models for the following parts are available in LTspice:
LT1251

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