AD688AQ Detailed explanation of pin function specifications and circuit principle instructions

The part number you provided, "AD688AQ," is a specific model from Analog Devices, a well-known manufacturer of analog, mixed-signal, and digital signal processing integrated circuits (ICs). The "AD688AQ" specifically refers to a Precision Voltage Reference device.

Pin Function Specifications and Circuit Principle

Let's break down the requested information step by step.

1. Brand and Model

Brand: Analog Devices Model: AD688AQ Part Type: Precision Voltage Reference (Dual Output)

2. Package Type and Pin Count

The AD688AQ is available in a 20-lead SOIC (Small Outline Integrated Circuit) package.

Package Type: 20-lead SOIC Pin Count: 20 pins

3. Pin Function List (Detailed, 20-pin Package)

Here is the detailed pinout and functionality for the AD688AQ in its 20-lead SOIC package:

Pin Number Pin Name Function Description 1 VOUT1 Output voltage 1 (VREF1), typically 5V, provided by the voltage reference circuit. 2 VOUT2 Output voltage 2 (VREF2), typically 5V, provided by the voltage reference circuit. 3 VCM Common voltage (input/output), usually connected to a mid-supply voltage in differential mode applications. 4 GND Ground pin for the circuit, provides the reference point for the voltage levels. 5 VOUT1+ Positive terminal of output voltage 1 (VREF1). 6 VOUT1- Negative terminal of output voltage 1 (VREF1). 7 VOUT2+ Positive terminal of output voltage 2 (VREF2). 8 VOUT2- Negative terminal of output voltage 2 (VREF2). 9 VCC Supply voltage pin, usually connected to the positive voltage source. 10 NC No connection (internal or unconnected pin). 11 NC No connection (internal or unconnected pin). 12 OUT1 Output voltage 1, usually represents the main output of the reference circuit. 13 OUT2 Output voltage 2, the secondary reference output. 14 NC No connection (internal or unconnected pin). 15 REF1 Reference input for output 1, usually used to set the reference voltage level. 16 REF2 Reference input for output 2, used to set the reference voltage level for output 2. 17 NC No connection (internal or unconnected pin). 18 SENSE1 Sensing input for output voltage 1, used to monitor the output voltage level. 19 SENSE2 Sensing input for output voltage 2, used to monitor the output voltage level. 20 GND Ground pin (additional ground pin for reference).

4. Pin Function FAQs (20 Frequently Asked Questions)

Q1: What is the function of pin 1 (VOUT1)? A1: Pin 1 (VOUT1) provides the output voltage 1, typically 5V, which is one of the main reference voltages from the AD688AQ.

Q2: What is pin 2 (VOUT2) used for? A2: Pin 2 (VOUT2) provides a secondary output voltage, usually set to 5V as well, from the voltage reference circuit in the AD688AQ.

Q3: What does the VCM pin (Pin 3) do? A3: Pin 3 (VCM) is the common voltage, usually connected to a mid-supply voltage in differential applications to maintain proper voltage levels.

Q4: Can I use Pin 4 (GND) as a ground for other parts of my circuit? A4: Yes, Pin 4 (GND) is the ground pin and serves as the reference for all the voltages in the AD688AQ circuit.

Q5: How are Pin 5 (VOUT1+) and Pin 6 (VOUT1-) used? A5: Pin 5 (VOUT1+) is the positive terminal for the first output voltage, and Pin 6 (VOUT1-) is the negative terminal for the same output.

Q6: What is the function of Pin 7 (VOUT2+)? A6: Pin 7 (VOUT2+) is the positive terminal for the second output voltage (VREF2).

Q7: What about Pin 8 (VOUT2-)? A7: Pin 8 (VOUT2-) is the negative terminal for the second output voltage (VREF2).

Q8: How should Pin 9 (VCC) be connected? A8: Pin 9 (VCC) is the supply voltage pin, typically connected to the positive power source to drive the reference voltage circuitry.

Q9: What is Pin 10 (NC) for? A9: Pin 10 (NC) is a "no connection" pin, meaning it is not internally connected to any circuitry within the AD688AQ.

Q10: What is the significance of Pin 12 (OUT1)? A10: Pin 12 (OUT1) is the main output of the AD688AQ, providing the first reference voltage (VREF1).

Q11: Is Pin 13 (OUT2) similar to Pin 12? A11: Yes, Pin 13 (OUT2) provides the second reference voltage (VREF2), similar to Pin 12 but for the second output.

Q12: What does Pin 15 (REF1) control? A12: Pin 15 (REF1) is the reference input for output 1, used to set the level of the first reference voltage output (VREF1).

Q13: How about Pin 16 (REF2)? A13: Pin 16 (REF2) is the reference input for output 2, used to control the level of the second reference voltage output (VREF2).

Q14: Why are there "No Connection" pins like Pin 11 and Pin 17? A14: "No Connection" pins (NC) are either unconnected internally or reserved for future use, and do not affect the circuit's function.

Q15: Can I connect Pin 18 (SENSE1) to an external sensor? A15: Yes, Pin 18 (SENSE1) is used for monitoring the voltage level of output 1, and can be connected to a sensing circuit if needed.

Q16: What is the purpose of Pin 19 (SENSE2)? A16: Pin 19 (SENSE2) is used to monitor the voltage level of output 2, similar to Pin 18 but for the second reference output.

Q17: Can Pin 4 (GND) and Pin 20 (GND) be tied together? A17: Yes, both Pin 4 and Pin 20 are ground pins, and can be tied together for better grounding in the circuit.

Q18: Is the AD688AQ suitable for use in high-precision voltage reference applications? A18: Yes, the AD688AQ is designed specifically for high-precision voltage reference applications and provides accurate output voltages.

Q19: What are the common uses for the AD688AQ? A19: The AD688AQ is commonly used in power supplies, instrumentation, ADC/DAC circuits, and any application requiring stable and precise reference voltages.

Q20: How do I ensure the AD688AQ operates correctly in my circuit? A20: To ensure proper operation, ensure stable input voltage at VCC (Pin 9), proper grounding (GND pins), and correct external components connected to the reference inputs (REF1, REF2).

This explanation covers the pin functions, as well as answers to the frequently asked questions (FAQs) for the AD688AQ in a detailed manner.