Features and Benefits
- Replaces Hybrid Amplifiers in Many Applications
- Settles to 0.01% in 350 ns
- 100 V/µs Slew Rate
- 12.8 MHz Min Unity Gain Bandwidth
- 1.75 MHz Full Power Bandwidth at 20 V p-p
- 0.25 mV Max Input Offset Voltage
- 5 µV/°C Max Offset Voltage Drift
- 0.5 nA Input Bias Current
- 250 V/mV Min Open-Loop Gain
- 4 µV p-p Max Voltage Noise, 0.1 Hz to 10 Hz
- 94 dB Min CMRR
- Available in Plastic Mini-DIP, Hermetic CERDIP, and SOIC Packages. Also available in Tape and Reel in Accordance with EIA-481A Standard
Product DetailsThe AD845 is a fast, precise, N channel JFET input, monolithic operational amplifier. It is fabricated using Analog Devices' complementary bipolar (CB) process. Advanced laser-wafer trimming technology enables the very low input offset voltage and offset voltage drift performance to be realized. This precision, when coupled with a slew rate of 100 V/µs, a stable unity-gain bandwidth of 16 MHz, and a settling time of 350 ns 0.01%-while driving a parallel load of 100 pF and 500 Ohm- represents a combination of features unmatched by any FET input IC amplifier. The AD845 can easily be used to upgrade many existing designs which use BiFET or FET input hybrid amplifiers and, in some cases, those which use bipolar input op amps.
The AD845 is ideal for use in applications such as active filters, high speed integrators, photo diode preamps, sample-and-hold amplifiers, log amplifiers, and in buffering A/D and D/A converters. The 250 µV max input offset voltage makes offset nulling unnecessary in many applications. The common-mode rejection ratio of 110 dB over a ±10 V input voltage range represents exceptional performance for a JFET input high speed op amp. This, together with a minimum open-loop gain of 250 V/mV ensures that 12-bit performance is achieved, even in unity-gain buffer circuits.
The AD845 conforms to the standard op amp pinout except that offset nulling is to V+. The AD845J and AD845K grade devices are available specified to operate over the commercial 0°C to +70°C temperature range. AD845A and AD845B devices are specified for operation over the -40°C to +85°C industrial temperature range. The AD845S is specified to operate over the full military temperature range of -55°C to +125°C. Both the industrial and military versions are available in 8-pin cerdip packages. The commercial version is available in an 8-pin plastic mini-DIP and 16-pin SOIC; "J" and "S" grade chips are also available.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Application Notes (4)
Tools & Simulations
AD845 SPICE Macro Models
ADIsimPE, which is powered by SIMetrix/SIMPLIS, is a circuit simulation suite optimized for the design and development of analog and mixed signal circuits. SIMetrix mode is ideal for the simulation of general non-switching circuits. It provides full Pspice compatibility for use with industry-standard SPICE models. SIMPLIS (SIMulation Piecewise-Linear System) mode simulates the operation of switching circuits with vastly improved robustness, speed, and accuracy compared to standard SPICE. It is particularly useful for switching power supply, PLLs, and ADC/DAC applications.
Use the Analog Filter Wizard to design low-pass, high-pass, or band-pass filters with actual op amps in minutes. As you progress through the design process, you can observe the characteristics of your filter design from ideal specifications to real world circuit behavior. Quickly evaluate the tradeoffs in op amp specifications - including gain-bandwidth, noise, and supply current – to determine the best filter design for your requirements.
Use Photodiode Wizard to design a transimpedance amplifier circuit to interface with a photodiode. Select a photodiode from the library included in the tool, or enter custom photodiode specifications. Quickly observe tradeoffs between Bandwidth, Peaking (Q), and ENOB/SNR. Modify circuit parameters, and immediately see results in plots for pulse response, frequency response, and noise gain.
A utility to convert between standard units of power measurement and signal strength.
This tool estimates die temperature and power dissipation based on the supply voltages, ambient temperature, load characteristics, and package thermal data.
Analog Dialogue (1)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.