Pendulum Instruments · High-Voltage Linear Amplifiers
A800
Single-channel ±400V wideband high-voltage linear amplifier for high-impedance and capacitive loads
The A800 is the highest-voltage single-channel model: ±400 V (800 Vp-p), gain x100, nominal input ±4 V. Output current is 60 mA continuous. Note that figure: it is lower than the ±200 V A400 because, within a fixed power budget, voltage and current trade against each other. The A800 therefore suits high-voltage, low-current loads: static or low-frequency drive of long-travel piezo stacks, electrostatic transducers and high-impedance measurement setups. If you need full swing into a large capacitance at high frequency, current becomes the limit first.
Overview
Voltage and current are usually listed separately on an amplifier specification sheet, but in practice both are bound by the same power budget, and that is where selection most often goes wrong. The A800 delivers ±400 V, the top of this series, at the cost of 60 mA continuous output current. For a capacitive load, the highest frequency at which full swing can be held is roughly the current divided by capacitance times voltage swing, so a large piezo stack can be positioned statically and driven at low frequency on the A800 but cannot swing full scale at tens of kHz. That is not a defect; it reflects the loads the unit is designed for: electrostatic transducers, high-impedance devices and long-travel low-frequency positioning, all high-voltage and low-current. The x100 gain lets a small signal source drive it directly, with the same signal-chain advantages as the A600. If your load needs both high voltage and high current, a different trade-off point applies. Give us the load capacitance and operating frequency when you request a quotation and we will confirm feasibility.
Key specifications
| Channels | 1 |
|---|---|
| Voltage gain | 100x (fixed) |
| Output voltage range | ±400 V (bipolar, 800 Vp-p) |
| Maximum input voltage | ±4 V (nominal) |
| Output current limit | 60 mA (continuous) |
| Maximum output power | ~30 W |
| Bandwidth (100 Vpp) | DC to 1 MHz |
| Bandwidth (maximum output voltage) | DC to 300 kHz |
| Slew rate | 500 V/µs (no load); full-bandwidth capacitive load 120 pF (the A800 manual states a 300 pF maximum) |
| Input impedance | 1 MΩ (30 pF) |
| Output impedance | <0.1 Ω |
| Mains supply | 100 V, 120 V or 230 V factory set, 50/60 Hz, or a 110/220 V line voltage selector |
| Dimensions (W × H × D) | 257 × 102 × 262 mm |
| Weight | 4 kg |
Features
±400 V, the highest in the series
800 Vp-p of swing for long-travel piezo stacks and electrostatic transducers.
Voltage traded for current
60 mA continuous is below the A400; that follows from a fixed power budget, so choose by load type.
Suited to high-impedance loads
Electrostatic devices, high-impedance measurement setups and low-frequency long-travel positioning are voltage-led rather than current-led.
x100 gain
A small control signal drives the output directly with no preamplifier.
Calculate before choosing
Send us the load capacitance and highest operating frequency; the frequency limit for full swing is set by the current.
Not only for piezo
Resistive and small capacitive loads (about 120 pF at full bandwidth) are fine, so high-voltage functional test, insulation stress test and arbitrary high-voltage waveform reproduction all apply.
Typical applications
Piezo drive
Piezo actuator and nanopositioning system drive
In precision positioning and vibration control research, the low-voltage output of a function generator (within ±4 V) has to be raised to several hundred volts before a PZT stack or piezo motor produces useful displacement. The A800 amplifies it linearly by a fixed 100 to ±400 V (800 Vp-p), and its 60 mA continuous current with low output impedance (<0.1 Ω) keeps displacement linear under scanning and dynamic load conditions.
MEMS testing
MEMS electrostatic actuator characterization and reliability testing
The electrostatic drive electrodes of MEMS devices often need several hundred volts of bias to cross the pull-in threshold, so characterization and lifetime tests apply repeatable high-voltage waveforms to a capacitive load. The wideband linear output of the A800 (DC to about 300 kHz) and its 500 V/µs slew rate let a lab measure the full electrostatic actuation curve with an arbitrary waveform generator and one amplifier, with no custom high-voltage supply to design.
Optoelectronics research
Liquid crystal and electro-optic modulator drive research
Switching voltages of liquid crystal devices and electro-optic (EO) modulators can reach several hundred volts, so optical phase modulation, spatial light modulator (SLM) calibration and display research need a general-purpose amplifier that outputs accurate high-voltage waveforms. The bipolar output of the A800 drives a liquid crystal cell symmetrically between positive and negative voltage, which suppresses aging from ion migration, and it is a common fixture in academic labs and device R&D departments for electro-optical measurement.
Options and configuration
Tick the options you need; the configuration list is compiled and carried into the quotation form.
Standard equipment (included)
Factory options (state your needs when ordering)
Related models (other channel counts and voltages)
Downloads
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