Key facts
- Brand
- Analog Devices
- Model
- AD7669
- Industry
- Industrial
- Documents
- 3
- Languages
- EN
- Last added
- 2012-08-02
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Analog Devices AD7569/AD7669 Application Note AN-222 Operation with Offset Signal Grounds for Disk Drive Applications
Single rail power supplies are common in disk drive circuits, but sensor and control signals often require a voltage above ground potential. Using standard ADCs or DACs with these offset levels can reduce dynamic range due to unused codes or deadbands.
The AD7569/AD7669 is an 8-bit A/D and D/A system that allows operation with offset grounds for both the ADC and DAC independently. This configuration maintains full dynamic range by biasing the analog grounds (AGNDadc, AGNDdac) to match the signal offsets.
Analog Devices AD7669 specifications
| Power Supply | single 5 V power supply |
|---|---|
| Signal Ranges | 0 to 1.25 V or 0 to 2.5 V |
| ADC Resolution | 8-bit |
| ADC Linearity Error Degradation | 0.2 LSBs at 0.5 V offset |
| DAC Linearity Error Degradation | less than 0.1 LSB at 0.5 V offset |
All Analog Devices AD7669 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
How to use the product for one specific task, with worked examples.
Questions answered in these manuals
Can the AD7569/AD7669 grounds be connected together?
Yes, in most applications these independent ground connections would be externally connected together.
What capacitor value is recommended for decoupling pseudo grounds?
The pseudo grounds should be decoupled using 0.1 µF capacitors.
What is the conversion time of the AD7569 ADC?
The conversion time with an external clock is a maximum of 2 µs.
From: Analog Devices AD7569/AD7669 8-Bit Analog I/O System Datasheet
Does the AD7569/AD7669 require external components?
No, it provides everything necessary to interface a microprocessor to the analog world without external components or user trims.
From: Analog Devices AD7569/AD7669 8-Bit Analog I/O System Datasheet
What is the resolution of the AD7569/AD7669?
Both devices have an 8‑bit resolution.
From: Analog Devices AD7569/AD7669 Complete 8‑Bit Analog I/O Systems Datasheet
What is the typical conversion time with an external clock?
The conversion time is up to 2 ns when using an external clock.
From: Analog Devices AD7569/AD7669 Complete 8‑Bit Analog I/O Systems Datasheet