Overview
The AD549JH is a monolithic electrometer operational amplifier produced by Analog Devices Inc. It is renowned for its ultralow input bias current, achieved through Analog Devices' exclusive Topgate™ JFET technology. This technology allows for the fabrication of extremely low input current JFETs, making the AD549JH ideal for applications requiring minimal input current and low input offset voltage. The device is laser trimmed for precision performance, ensuring low input offset voltage and drift. It is available in a TO-99 hermetic package and is pin compatible with standard FET and electrometer op amps, facilitating easy upgrades in existing systems.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Bias Current | - | 60 fA | 100 fA | A |
| Input Offset Voltage | - | 0.5 mV (AD549K) | 1 mV (AD549J) | mV |
| Input Offset Voltage Drift | - | 15 μV/°C (AD549K) | 20 μV/°C (AD549J) | μV/°C |
| Unity Gain Bandwidth | 0.7 | 1.0 | - | MHz |
| Slew Rate | 2 | 3 | - | V/μs |
| Supply Voltage | - | - | ±18 V | V |
| Operating Temperature Range | 0°C (AD549J, AD549K, AD549L) | - | +70°C (AD549J, AD549K, AD549L) | °C |
| Operating Temperature Range (Military Grade) | -55°C (AD549S) | - | +125°C (AD549S) | °C |
Key Features
- Ultralow Input Bias Current: Achieved through Topgate™ JFET technology, ensuring minimal input current.
- Precision Performance: Laser trimmed input offset voltage and drift for high accuracy.
- Low Quiescent Supply Current: Maximum of 700 μA to minimize heating effects on input current and offset voltage.
- High Bandwidth and Slew Rate: 1 MHz unity-gain bandwidth and 3 V/μs slew rate.
- Hermetic Packaging: Available in a TO-99 hermetic package, with the case connected to Pin 8 for minimizing stray leakage.
- Military Grade Option: The AD549S is specified over the military temperature range and is available processed to MIL-STD-883B, Rev. C.
Applications
- Current Output Transducers: Ideal as a preamp for photodiodes, photomultiplier tubes, or oxygen sensors.
- Precision Integrator and Sample-and-Hold Circuits: Excels in applications requiring low droop and high precision.
- Electrometer Applications: Suited for any application requiring very low input current and low input offset voltage.
Q & A
- What is the primary feature of the AD549JH operational amplifier?
The AD549JH is primarily known for its ultralow input bias current, achieved through Topgate™ JFET technology.
- What are the typical input offset voltage and drift specifications for the AD549JH?
The input offset voltage is typically 0.5 mV (AD549K) and 1 mV (AD549J), with drifts of 15 μV/°C (AD549K) and 20 μV/°C (AD549J).
- What is the unity gain bandwidth of the AD549JH?
The unity gain bandwidth is typically 1 MHz.
- What is the maximum supply voltage for the AD549JH?
The maximum supply voltage is ±18 V.
- What are the operating temperature ranges for the AD549JH?
The commercial grades (AD549J, AD549K, AD549L) operate from 0°C to +70°C, while the military grade (AD549S) operates from -55°C to +125°C.
- What type of packaging is the AD549JH available in?
The AD549JH is available in a TO-99 hermetic package.
- Can the AD549JH be used in precision integrator circuits?
Yes, the AD549JH excels as a precision integrator due to its low input bias current and offset voltage.
- Is the AD549JH compatible with standard FET and electrometer op amps?
Yes, it is pin compatible, allowing for easy upgrades in existing systems..
- What are some common applications for the AD549JH?
Common applications include preamps for current output transducers, precision integrators, and sample-and-hold circuits..
- Does the AD549JH have any military-grade options?
Yes, the AD549S is the military-grade version, specified over the military temperature range and available processed to MIL-STD-883B, Rev. C..
