Overview
The LF398N/NOPB 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 times and low droop rates. This device operates as a unity-gain follower, offering a DC gain accuracy of 0.002% and an acquisition time as low as 6 µs to 0.01%. The LF398N/NOPB is designed to provide low input offset voltage, wide bandwidth, and high supply rejection ratio in both sample and hold modes.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage | ±5 | - | ±18 | V |
| Acquisition Time (Ch = 0.01 µF) | - | 20 | - | µs |
| Input Offset Voltage (Tj = 25°C) | 1 | 3 | 7 | mV |
| Input Bias Current (Tj = 25°C) | 5 | 25 | 75 | nA |
| Input Impedance (Tj = 25°C) | 10^10 | - | - | Ω |
| Gain Error (Tj = 25°C, RL = 10 kΩ) | 0.002 | 0.005 | 0.02 | % |
| Output Impedance (Tj = 25°C, HOLD mode) | 0.5 | 2 | 4 | Ω |
| HOLD Step (Tj = 25°C, Ch = 0.01 µF, VOUT = 0) | 0.5 | 2 | - | mV |
| Supply Current (Tj ≥ 25°C) | 4.5 | 5.5 | 6.5 | mA |
| Operating Ambient Temperature | 0 | - | 70 | °C |
Key Features
- Operates from ±5-V to ±18-V supplies.
- Less than 10-µs acquisition time.
- Logic input compatible with TTL, PMOS, CMOS.
- 0.5-mV typical hold step at Ch = 0.01 µF.
- Low input offset voltage and high gain accuracy (0.002%).
- Low output noise in hold mode.
- Input characteristics do not change during hold mode.
- High supply rejection ratio in sample or hold mode.
- Wide bandwidth and space qualified (JM38510).
Applications
The LF398N/NOPB is suitable for various applications requiring precise signal sampling and holding, such as in data acquisition systems, analog-to-digital converters, and other high-accuracy analog circuits. It can be used in environments where fast acquisition times and low droop rates are critical. Additionally, its compatibility with TTL, PMOS, and CMOS logic makes it versatile for integration into a wide range of digital and analog systems.
Q & A
- What is the typical acquisition time of the LF398N/NOPB?
The typical acquisition time is less than 10 µs, specifically 20 µs for a 0.01 µF hold capacitor.
- What is the input offset voltage of the LF398N/NOPB?
The input offset voltage is typically 3 mV at 25°C and up to 7 mV over the full temperature range.
- What is the supply voltage range for the LF398N/NOPB?
The device operates from ±5-V to ±18-V supplies.
- Is the LF398N/NOPB compatible with different logic families?
Yes, it is compatible with TTL, PMOS, and CMOS logic inputs.
- What is the typical hold step of the LF398N/NOPB?
The typical hold step is 0.5 mV at Ch = 0.01 µF.
- What is the gain accuracy of the LF398N/NOPB?
The gain accuracy is typically 0.002%.
- Does the LF398N/NOPB have high supply rejection ratio?
Yes, it has a high supply rejection ratio in both sample and hold modes, typically 80 to 110 dB.
- What is the operating ambient temperature range for the LF398N/NOPB?
The operating ambient temperature range is from 0°C to 70°C.
- Is the LF398N/NOPB space qualified?
Yes, it is space qualified to JM38510 standards.
- What is the typical supply current of the LF398N/NOPB?
The typical supply current is 5.5 mA at Tj ≥ 25°C.
