Overview
The LMH6518SQE/NOPB is a digitally controlled variable gain amplifier designed by Texas Instruments. This device is specifically tailored to drive high-speed analog-to-digital converters (ADCs) with a 100-Ω input impedance and an 800 mVPP full-scale input voltage. It features a wide gain range of 40 dB, adjustable in 2 dB steps, and a combined gain resolution of 8.5 mdB when used with gigasamples per second (GSPS) ADCs. The LMH6518 is characterized by its high bandwidth of 900 MHz across all gain settings, making it suitable for high-frequency applications.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Gain Range | -1.16 dB | - | 38.8 dB | dB |
| Gain Step Size | - | 2 dB | - | dB |
| -3 dB Bandwidth | - | 900 MHz | - | MHz |
| Rise Time | - | 460 ps | - | ps |
| Fall Time | - | 450 ps | - | ps |
| Recovery Time | - | < 5 ns | - | ns |
| Propagation Delay Variation | - | 100 ps | - | ps |
| Input-Referred Noise (Max Gain) | - | 0.98 nV/√Hz | - | nV/√Hz |
| Power Consumption (Auxiliary Off) | 0.75 W | - | 1.1 W | W |
| Junction Temperature | - | - | 150 °C | °C |
Key Features
- Digitally controlled variable gain with a 40 dB range in 2 dB steps
- High bandwidth of 900 MHz across all gain settings
- Combined gain resolution of 8.5 mdB with GSPS ADCs
- Fast rise and fall times (< 500 ps) and recovery time (< 5 ns)
- Low input-referred noise (0.98 nV/√Hz at maximum gain)
- Overvoltage clamps for fast recovery
- Differential outputs with individual common-mode voltage control
- Selectable bandwidth limiting circuitry
- Programmable via SPI-compatible serial bus
Applications
- Oscilloscope programmable gain amplifiers
- Differential ADC drivers
- High-frequency single-ended input to differential conversion
- Precision gain control applications
- Medical applications
- RF/IF applications
Q & A
- What is the gain range of the LMH6518?
The LMH6518 has a gain range of -1.16 dB to 38.8 dB.
- What is the bandwidth of the LMH6518?
The -3 dB bandwidth of the LMH6518 is 900 MHz across all gain settings.
- How is the gain of the LMH6518 programmed?
The gain is programmed through a SPI-compatible serial bus.
- What are the typical rise and fall times of the LMH6518?
The typical rise and fall times are less than 500 ps.
- What is the recovery time of the LMH6518?
The recovery time is less than 5 ns.
- What is the input-referred noise at maximum gain?
The input-referred noise at maximum gain is 0.98 nV/√Hz.
- Does the LMH6518 have overvoltage protection?
Yes, the LMH6518 features overvoltage clamps for fast recovery.
- What are the common applications of the LMH6518?
Common applications include oscilloscope programmable gain amplifiers, differential ADC drivers, high-frequency single-ended to differential conversion, precision gain control, medical applications, and RF/IF applications.
- What is the package type and size of the LMH6518?
The LMH6518 comes in a 16-pin WQFN package with a size of 4mm x 4mm.
- What is the junction temperature limit of the LMH6518?
The junction temperature limit is 150 °C.
