Overview
The AD549LHZ 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 AD549LHZ ideal for applications requiring very low input current and low input offset voltage. The device is laser trimmed for precision performance, ensuring high accuracy in its 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 | 200 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 |
| Settling Time (0.1%) | 4.5 | - | - | μs |
| Supply Voltage | - | - | ±18 V | V |
| Operating Temperature Range | 0°C to +70°C (AD549J, AD549K, AD549L) | - | -55°C to +125°C (AD549S) | °C |
Key Features
- Ultralow Input Bias Current: Achieved through Topgate™ JFET technology, ensuring extremely low 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 AC Performance: 1 MHz unity-gain bandwidth and 3 V/μs slew rate.
- Pin Compatibility: Compatible with standard FET and electrometer op amps, facilitating easy system upgrades.
- Hermetic Packaging: Available in a TO-99 hermetic package with the case connected to Pin 8 for minimizing stray leakage.
Applications
- Preamp for Current Output Transducers: Suitable for photodiodes, photomultiplier tubes, and oxygen sensors.
- Precision Integrator: Can be used as a precision integrator due to its low input bias current and offset voltage.
- Low Droop Sample-and-Hold: Ideal for applications requiring low droop sample-and-hold circuits.
Q & A
- What is the primary technology behind the AD549LHZ's low input bias current?
The AD549LHZ uses Analog Devices' exclusive Topgate™ JFET technology to achieve its ultralow input bias current.
- What are the typical input offset voltage and drift specifications for the AD549K?
The typical input offset voltage is 0.5 mV, and the drift is 15 μV/°C for the AD549K.
- What is the maximum quiescent supply current of the AD549LHZ?
The maximum quiescent supply current is 700 μA).
- What is the unity-gain bandwidth of the AD549LHZ?
The unity-gain bandwidth is typically 1 MHz).
- What types of packages are available for the AD549LHZ?
The AD549LHZ is available in a TO-99 hermetic package).
- What are some common applications of the AD549LHZ?
Common applications include preamps for current output transducers, precision integrators, and low droop sample-and-hold circuits).
- What is the operating temperature range for the AD549J, AD549K, and AD549L versions?
The operating temperature range is 0°C to +70°C for the AD549J, AD549K, and AD549L versions).
- What is the operating temperature range for the AD549S version?
The operating temperature range is −55°C to +125°C for the AD549S version).
- Is the AD549LHZ pin compatible with other FET and electrometer op amps?
Yes, the AD549LHZ is pin compatible with standard FET and electrometer op amps).
- What is the significance of the metal case being connected to Pin 8 in the TO-99 package?
The metal case can be independently connected to a point at the same potential as the input terminals, minimizing stray leakage to the case).
