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Features
- Very Fast Transconductance Amplifier
- Bandwidth: 75MHz
- Outputs Swing Within 0.8V of Supplies
- gm = 10 × ISET
- Low THD: 0.2% at 30mVRMS Input
- Wide ISET Range: 1µA to 1mA
- Very Fast Current Feedback Amplifier
- Bandwidth: 100MHz
- Slew Rate: 1000V/µs
- Output Drive Current: 30mA
- Differential Gain: 0.04%
- Differential Phase: 0.1°
- High Input Impedance: 25MΩ, 6pF
- Wide Supply Range: ±2V to ±15V
- Inputs Common Mode to Within 1.5V of Supplies
- Supply Current: 7mA
- Available in 8-Lead PDIP and SOIC Packages
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The LT1228 makes it easy to electronically control the gain of signals from DC to video frequencies. The LT1228 implements gain control with a transconductance amplifier (voltage to current) whose gain is proportional to an externally controlled current. A resistor is typically used to convert the output current to a voltage, which is then amplified with a current feedback amplifier. The LT1228 combines both amplifiers into an 8-pin package, and operates on any supply voltage from 4V (±2V) to 30V (±15V). A complete differential input, gain controlled amplifier can be implemented with the LT1228 and just a few resistors.
The LT1228 transconductance amplifier has a high impedance differential input and a current source output with wide output voltage compliance. The transconductance, gm, is set by the current that flows into Pin5, ISET. The small signal gm is equal to ten times the value of ISET and this relationship holds over several decades of set current. The voltage at Pin 5 is two diode drops above the negative supply, Pin 4.
The LT1228 current feedback amplifier has very high input impedance and therefore it is an excellent buffer for the output of the transconductance amplifier. The current feedback amplifier maintains its wide bandwidth over a wide range of voltage gains making it easy to interface the transconductance amplifier output to other circuitry. The current feedback amplifier is designed to drive low impedance loads, such as cables, with excellent linearity at high frequencies.
Applications
- Video DC Restore (Clamp) Circuits
- Video Differential Input Amplifiers
- Video Keyer/Fader Amplifiers
- AGC Amplifiers
- Tunable Filters
- Oscillators
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LT1228
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Data Sheet 1
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Application Note 5
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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LT1228CN8#PBF |
8-Lead PDIP (Narrow 0.3 Inch)
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| LT1228CS8#PBF |
8-Lead SOIC (Narrow 0.15 Inch)
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| LT1228CS8#TRPBF |
8-Lead SOIC (Narrow 0.15 Inch)
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| LT1228IN8#PBF |
8-Lead PDIP (Narrow 0.3 Inch)
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| LT1228IS8#PBF |
8-Lead SOIC (Narrow 0.15 Inch)
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| LT1228IS8#TRPBF |
8-Lead SOIC (Narrow 0.15 Inch)
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- LT1228CN8#PBF
- Pin/Package Drawing
-
8-Lead PDIP (Narrow 0.3 Inch)
- Documentation
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HTML
Material Declaration
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HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
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Ultra Librarian
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SamacSys
- LT1228CS8#PBF
- Pin/Package Drawing
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8-Lead SOIC (Narrow 0.15 Inch)
- Documentation
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HTML
Material Declaration
-
HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
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Ultra Librarian
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SamacSys
- LT1228CS8#TRPBF
- Pin/Package Drawing
-
8-Lead SOIC (Narrow 0.15 Inch)
- Documentation
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HTML
Material Declaration
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HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
-
Ultra Librarian
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SamacSys
- LT1228IN8#PBF
- Pin/Package Drawing
-
8-Lead PDIP (Narrow 0.3 Inch)
- Documentation
-
HTML
Material Declaration
-
HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
-
Ultra Librarian
-
SamacSys
- LT1228IS8#PBF
- Pin/Package Drawing
-
8-Lead SOIC (Narrow 0.15 Inch)
- Documentation
-
HTML
Material Declaration
-
HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
-
Ultra Librarian
-
SamacSys
- LT1228IS8#TRPBF
- Pin/Package Drawing
-
8-Lead SOIC (Narrow 0.15 Inch)
- Documentation
-
HTML
Material Declaration
-
HTML
Reliablity Data
- CAD Symbols, Footprints, and 3D Models
-
Ultra Librarian
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SamacSys
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Product Lifecycle
PCN
Oct 11, 2022
- 22_0241
Epoxy Change from Henkel 8290 to 8290A for PDIP Package
LT1228CN8#PBF
PRODUCTION
LT1228IN8#PBF
PRODUCTION
Aug 6, 2022
- 22_0172
Laser Top Mark Conversion for PDIP Packages Assembled in ADPG [PNG]
LT1228CN8#PBF
PRODUCTION
LT1228IN8#PBF
PRODUCTION
Dec 14, 2023
- 22_0255
Epoxy Change from Henkel 8290 to 8290A for 8-Lead SOIC Package (PCN part 2 of 2)
LT1228CS8#PBF
PRODUCTION
LT1228CS8#TRPBF
PRODUCTION
LT1228IS8#PBF
PRODUCTION
LT1228IS8#TRPBF
PRODUCTION
Jun 11, 2021
- 21_0060
Laser Top Mark for 8SOICN Assembled in ADPG, UTL and CRM
LT1228CS8#PBF
PRODUCTION
LT1228CS8#TRPBF
PRODUCTION
LT1228IS8#PBF
PRODUCTION
LT1228IS8#TRPBF
PRODUCTION
Filter by Model
Part Models
Product Lifecycle
PCN
Oct 11, 2022
- 22_0241
Epoxy Change from Henkel 8290 to 8290A for PDIP Package
LT1228CN8#PBF
PRODUCTION
LT1228IN8#PBF
PRODUCTION
Aug 6, 2022
- 22_0172
Laser Top Mark Conversion for PDIP Packages Assembled in ADPG [PNG]
LT1228CN8#PBF
PRODUCTION
LT1228IN8#PBF
PRODUCTION
Dec 14, 2023
- 22_0255
Epoxy Change from Henkel 8290 to 8290A for 8-Lead SOIC Package (PCN part 2 of 2)
LT1228CS8#PBF
PRODUCTION
LT1228CS8#TRPBF
PRODUCTION
LT1228IS8#PBF
PRODUCTION
LT1228IS8#TRPBF
PRODUCTION
Jun 11, 2021
- 21_0060
Laser Top Mark for 8SOICN Assembled in ADPG, UTL and CRM
LT1228CS8#PBF
PRODUCTION
LT1228CS8#TRPBF
PRODUCTION
LT1228IS8#PBF
PRODUCTION
LT1228IS8#TRPBF
PRODUCTION
Software & Part Ecosystem
Evaluation Kits 1
DC417B
DIP8, MS8, S8, SOT23-6 | Multi-Footprint General Purpose Board for Single Op. Amp
Product Detail
DC417B: Demo Board
Resources
Tools & Simulations 1
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Lt Spice
