A Sample & Hold Amplifier (SHA) acts like a “fast-shutter camera” for analog circuits. Analog signals change constantly. Some devices, like Analog-to-Digital Converters (ADCs), cannot process these signals fast enough. An SHA “snaps” the voltage at a specific moment and freezes it, allowing subsequent circuits time to process the data.
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Global Sample & Hold Amplifiers IC Manufacturers and Typical Models
1. Analog Devices (ADI)
ADI is a leader in high-performance signal chains.
Series
Typical Models
Features & Applications
High Speed / Wideband
AD783
Internal capacitor; 250ns acquisition time. Used in high-speed data systems.
Precision / General Purpose
AD585, AD781
Ultra-low offset voltage. Ideal for high-precision instrument front-ends.
Multi-channel (SMP)
SMP04, SMP08, SMP18
4/8/16 channels with low droop rates. Suitable for multiplexed demodulation.
Dual Channel
AD684
Two independent SHAs. Perfect for I/Q signal simultaneous sampling.
2. Texas Instruments (TI)
TI dominates the industrial standard and high-reliability markets.
Series
Typical Models
Features & Applications
Industry Benchmarks
LF198, LF298, LF398
The most famous SHA chips in history. External capacitor; high cost-performance.
Military / High Reliability
LM198, LM198-N
Wide-temperature versions of LF398. Common in aerospace and defense.
Specialized Integrated
SHC298
Optimized for specific industrial control environments.
3. Maxim Integrated (Now part of ADI)
Maxim focuses on low power and high integration.
Series
Typical Models
Features & Applications
High Speed, Low Power
MAX4100, MAX4101
Optimized for video signal processing; extremely high bandwidth.
Integrated with ADC
MAX125, MAX126
Integrated 2×4 channel SHA and ADC for synchronous data acquisition.
Low Voltage Single Supply
MAX4140
Suitable for 3V/5V portable devices.
4. Renesas / Intersil
Renesas maintains specialized “HA” series chips for radar and imaging.
Series
Typical Models
Features & Applications
Ultra-High Speed
HA-5351
~70ns acquisition time. Designed for radar and image processing.
Industrial Standard
HA-2420, HA-5320
Legacy standards still widely used in existing equipment.
High Input Impedance
HA-2425
Extremely high input resistance for weak signals from high-impedance sensors.
Chinese Domestic Manufacturers and Typical Models
Chinese firms primarily focus on “Pin-to-Pin” replacements for TI/ADI standards and high-reliability customization.
1. General Purpose and Performance Replacements
Manufacturer
Typical Models
Cross-Reference
Features & Applications
Corebai
CBM398
TI/National LF398
Most common domestic replacement. External capacitor for precision sampling.
Belling
BL398
TI/National LF398
Reliable legacy manufacturer. Common in power meters and industrial tools.
CETC (58th Institute)
54HC… Series
AD783 / HA-5320
High-performance analog front-ends; industrial-grade replacements.
3PEAK
TP… Series
Compatible Series
Often integrated into custom sample-and-hold circuits.
2. High Reliability and Special Applications
Manufacturer
Typical Models
Technical Background
Typical Applications
Xi’an Microelectronics (771st)
Custom Models
HA-5320 / AD585 Compat.
Wide temperature range for high-reliability grades.
Beijing Microelectronics (772nd)
BM Series
Mil-grade SHA Compat.
Radiation-hardened systems for aerospace.
Gausstek
GS… Series
High-perf Analog Chain
Customized solutions for high-speed signal acquisition.
Sample Phase: The internal switch closes. The charge flows into an internal or external hold capacitor. The output voltage follows the input.
Hold Phase: The switch opens. The capacitor “locks” the voltage. High input impedance in the buffer prevents charge leakage. The output stays constant.
The Trade-off: Designers must balance Acquisition Time (how fast it samples) with Droop Rate (how accurately it holds the voltage).
Typical Application Scenarios
ADC Front-End Buffering: Prevents “Aperture Error” during quantization by providing a stable “frozen image” of the signal.
Simultaneous Sampling: Captures multiple channels (e.g., 3-phase power) at the exact same moment.
DAC Deglitching: Suppresses spikes (glitches) during digital input transitions.
Peak Detection: Captures transient maximum voltages in radar or pressure tests.
Analog De-multiplexing: Distributes a single signal source to multiple processing circuits by “grabbing” specific time slots.
Detailed Classification of SHA ICs
1. By Performance and Speed
Speed determines the highest signal frequency a system can handle.
Category
Characteristics
Typical Models
Main Manufacturers
High Speed
Acquisition < 1µs.
AD783, HA-5320
ADI, Renesas
Precision
Acquisition 1µs – 20µs.
LF398, AD585
TI, ADI
2. By Channel Count
Selection depends on board space and synchronization needs.
Category
Characteristics
Typical Models
Main Manufacturers
Single Channel
Optimal performance for single signal paths.
LF198, AD781
TI, ADI
Multi-channel
4/8/16 channels for multiplexed systems.
SMP08, MAX125
ADI, Maxim
3. By Capacitor Architecture
This affects BOM complexity and tuning flexibility.
