Quick Start Guide for Demonstration Circuit 1150A: LT5554 7-Bit Digitally Controlled VGA
Demonstration circuit 1150A features the LT5554, a 7-bit programmable gain amplifier with a 16dB gain range, 0.125dB steps, and ultra-low distortion for broadband applications.
Overview
The DC1150A demonstration circuit showcases the LT5554, a broadband, ultra-low distortion 7-bit digitally controlled variable gain amplifier (VGA). The LT5554 provides a 16dB gain range with 0.125dB step resolution and a fast 5ns settling time, making it suitable for quasi-continuous gain control. The board is designed for flexibility, supporting single-ended or differential I/O via transformer or capacitive coupling. It operates on a 5V supply and is compatible with TTL, ECL, and CMOS control logic through a 3-state MODE pin. The document provides detailed performance specifications, pin descriptions, and modification guides for various output impedance configurations including 50Ω, 75Ω, and 100Ω environments.
Use Cases
- ADC driver interfacing
- Broadband communication systems
- Receiver gain control
- RF/IF signal conditioning
- Quasi-continuous gain control applications
Topics
Referenced Parts
Mini-Circuits
Replace R5 and R6 from 68.1• to 124•. T2(TC2-1T) replace with TC3-1T(Mini-Circuit)
Mini-Circuits
Replace R5 and R6 from 68.1• to 205•. T2(TC2-1T) replace with TC4-1W(Mini-Circuit)
LT5554EUH
Linear Technology
U1 LT5554EUH IF AMPLIFIER
LTC2208
Linear Technology
The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling.
LTC2209
Linear Technology
The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling.
LTC2254
Linear Technology
The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling.
LTC2255
Linear Technology
The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling.
ETC1-1-13
MACOM
T1 ETC1-1-13
LT5514
Linear Technology
please refer to the Application Note 97 (published for the related LT5514 part)
2.2V
Maxim
2.2V, MAXIMUM GAIN, POUT = 4dBm/Tone (2VP-P into 50Ω Ω Ω Ω), ∆∆∆∆f = 200KHz]
| TC2-1T | Mini-Circuits | T2 =TC2-1T. (Standard Demo Board installed with these components values) |
| TC3-1T+ | Mini-Circuits | Replace R5 and R6 from 68.1• to 124•. T2(TC2-1T) replace with TC3-1T(Mini-Circuit) |
| TC4-1W | Mini-Circuits | Replace R5 and R6 from 68.1• to 205•. T2(TC2-1T) replace with TC4-1W(Mini-Circuit) |
| LT5554EUH | Linear Technology | U1 LT5554EUH IF AMPLIFIER |
| LTC2208 | Linear Technology | The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling. |
| LTC2209 | Linear Technology | The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling. |
| LTC2254 | Linear Technology | The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling. |
| LTC2255 | Linear Technology | The LT5554 outputs can drive differentially a 3V ADC like LTC2254/5 LTC2208/9 with AC coupling. |
| ETC1-1-13 | MACOM | T1 ETC1-1-13 |
| LT5514 | Linear Technology | please refer to the Application Note 97 (published for the related LT5514 part) |
| 2.2V | Maxim | 2.2V, MAXIMUM GAIN, POUT = 4dBm/Tone (2VP-P into 50Ω Ω Ω Ω), ∆∆∆∆f = 200KHz] |