Overview
The LF198H is a monolithic sample-and-hold circuit produced by Texas Instruments. It utilizes BI-FET technology to achieve ultra-high DC accuracy with fast acquisition of signals and a low droop rate. This device operates as a unity-gain follower, offering a typical DC gain accuracy of 0.002% and an acquisition time as low as 6 µs to 0.01%. The LF198H is designed for high-performance applications requiring precise signal sampling and holding capabilities.
Key Specifications
| Parameter | Conditions | Typical | Min | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | ±5V | ±18V | V | ||
| Acquisition Time | 6 µs | 10 µs | µs | ||
| Gain Error | Tj = 25°C, RL = 10kΩ | 0.002% | 0.005% | % | |
| Input Offset Voltage | Tj = 25°C | 1 mV | 3 mV | mV | |
| Input Impedance | Tj = 25°C | 10 GΩ | Ω | ||
| Hold Step | Ch = 0.01 µF | 0.5 mV | 1 mV | mV | |
| Output Impedance (HOLD mode) | Tj = 25°C | 0.5 Ω | 2 Ω | Ω | |
| Feedthrough Attenuation Ratio at 1 kHz | Ch = 0.01 µF | 86 dB | 96 dB | dB |
Key Features
- Operates from ±5V to ±18V supplies
- Less than 10 µs acquisition time with fast signal acquisition
- TTL, PMOS, CMOS compatible logic input with fully differential logic inputs
- 0.5 mV typical hold step at Ch = 0.01 µF
- Low input offset voltage and wide bandwidth
- 0.002% gain accuracy and low output noise in hold mode
- High supply rejection ratio in sample or hold mode
- No feed-through from input to output in the hold mode
- Space qualified, JM38510
Applications
The LF198H is suitable for various high-performance applications, including:
- Signal processing and data acquisition systems
- High-speed sampling and holding in analog-to-digital converters
- Feedback loops of high-frequency operational amplifiers
- Aerospace and defense systems due to its space qualification
- Medical and industrial instrumentation requiring precise signal handling
Q & A
- What is the typical acquisition time of the LF198H?
The typical acquisition time of the LF198H is as low as 6 µs to 0.01%.
- What is the input impedance of the LF198H?
The input impedance of the LF198H is 10 GΩ.
- What are the compatible logic inputs for the LF198H?
The LF198H has TTL, PMOS, and CMOS compatible logic inputs.
- What is the typical hold step of the LF198H at a 0.01 µF capacitor?
The typical hold step of the LF198H at a 0.01 µF capacitor is 0.5 mV.
- What is the gain accuracy of the LF198H?
The gain accuracy of the LF198H is typically 0.002%.
- Does the LF198H exhibit feed-through from input to output in the hold mode?
No, the LF198H guarantees no feed-through from input to output in the hold mode.
- What is the supply voltage range for the LF198H?
The LF198H operates from ±5V to ±18V supplies.
- Is the LF198H space qualified?
- What is the output impedance of the LF198H in the HOLD mode?
The output impedance of the LF198H in the HOLD mode is typically 0.5 Ω.
- What is the feedthrough attenuation ratio at 1 kHz for the LF198H?
The feedthrough attenuation ratio at 1 kHz for the LF198H is typically 86 dB.
