Overview
The AD694JNZ, produced by Analog Devices Inc., is a monolithic current transmitter designed to drive a standard 4–20 mA current loop. This device is ideal for controlling valves, actuators, and other control devices, as well as transmitting process parameters such as pressure, temperature, or flow. It is particularly useful in industrial process control, factory automation, and system monitoring. The AD694JNZ is available in a 16-pin plastic DIP package and is specified over the 0°C to +70°C temperature range.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage Range | –0.2 VS | –2.0 V | VS –2.5 V | V |
| Input Bias Current | 1.5 | 5 | 1.5 | nA |
| Offset Current | ±0.1 | ±1 | ±0.1 | nA |
| Offset Current Drift | ±1.0 | ±5.0 | ±1.0 | pA/°C |
| Input Impedance | 5 | MΩ | ||
| Operating Current Range | 0 | 23 | 0 | mA |
| Output Voltage Compliance | VS –36 V | VS –2 V | V | |
| Output Impedance, 4–20 mA | 40.0 | 50.0 | 40.0 | MΩ |
| Current Limit (@ 2 × FS Overdrive) | 241 | 441 | 241 | mA |
| Slew Rate | 1.3 | mA/µs |
Key Features
- Complete voltage-to-4–20 mA current transmitter.
- Pin-programmable input ranges precalibrated at 0 V to 2 V and 0 V to 10 V.
- The input amplifier can be configured to buffer and scale the input voltage or serve as an output amplifier for current output DACs.
- Output voltage compliance extends to within 2 V of the positive supply and below common.
- Interfaces directly with 8-, 10-, and 12-bit single supply CMOS and bipolar DACs.
- The 4 mA zero current can be switched on and off with a TTL control pin, allowing 0–20 mA operation.
- An open collector alarm warns of loop failure due to open wires or noncompliance of the output stage.
- A monitored output is provided to drive an external pass transistor, off-loading power dissipation and minimizing self-heating error.
Applications
The AD694JNZ is recommended for use in various industrial and automation applications, including:
- Industrial process control.
- Factory automation.
- System monitoring.
- Control of valves, actuators, and other control devices.
- Transmission of process parameters such as pressure, temperature, or flow.
Q & A
- What is the primary function of the AD694JNZ?
The AD694JNZ is a monolithic current transmitter that converts high-level signal inputs into a standard 4–20 mA current loop. - What are the available input voltage ranges for the AD694JNZ?
The input voltage ranges are precalibrated at 0 V to 2 V and 0 V to 10 V. - What types of DACs does the AD694JNZ interface with?
The AD694JNZ interfaces directly with 8-, 10-, and 12-bit single supply CMOS and bipolar DACs. - How can the 4 mA zero current be controlled?
The 4 mA zero current can be switched on and off with a TTL control pin, allowing 0–20 mA operation. - What is the purpose of the open collector alarm in the AD694JNZ?
The open collector alarm warns of loop failure due to open wires or noncompliance of the output stage. - How does the monitored output feature work?
The monitored output drives an external pass transistor, off-loading power dissipation and minimizing self-heating error. - What are the temperature ranges for the AD694JNZ?
The AD694JNZ is specified over the 0°C to +70°C temperature range. - What package types are available for the AD694JNZ?
The AD694JNZ is available in a 16-pin plastic DIP package. - Can the AD694JNZ be used in industrial process control?
Yes, the AD694JNZ is highly recommended for industrial process control and similar applications. - How does the voltage reference feature work in the AD694JNZ?
A 2 V or 10 V voltage reference is available, selectable by pin-strapping, and can source up to 5 mA for user applications.
