This version is outdated by a newer approved version.
This version (03 Jul 2017 10:15) is a draft.
Approvals: 0/1
This version (03 Jul 2017 10:15) is a draft.Approvals: 0/1
This is an old revision of the document!
Table of Contents
AD7768-1 User Guide
Overview
The AD7768-1 is a low power, high performance, Σ-Δ ADC, with a Σ-Δ modulator and digital filter for precision conversion of both ac and dc signals. The AD7768-1 provides a single configurable and reusable Data Acquisition Footprint, which establishes a new industry standard in combined AC & DC performance, and enables Instrumentation and Industrial System designers to design across multiple measurement variants, for both isolated and non-isolated applications.
The AD7768-1 achieves 108 dB dynamic range when using the low ripple FIR digital filter at 256 kSPS giving 110.8 kHz input BW, combined with ±2 ppm INL, ±50 ìV zero error and ±30 ppm gain error.
Wider bandwidth, up to 500kHz Nyquitst, 250kHz -3dB, is available using the Sinc Filter, enabling a view of signals over an extended range.
The AD7768-1 offers the user the flexibility to configure and optimise for input bandwidth versus output data rate, and versus power dissipation. The selection of one of three available power modes allows the designer to achieve required noise targets while minimising power consumption. The design of the AD7768-1 is unique in that it becomes a reusable and flexible platform for low power dc and high performance ac measurement modules.
The AD7768-1 achieves the optimum balance of dc and ac performance with excellent power efficiency. The three operating modes allow the user to tailor the input bandwidth versus power budgets:
- FAST mode, Sinc filter
- Up to 1.024 MSPS and 250 kHz BW, TBD mW
- FAST mode, FIR filter
- Up to 256 kSPS, 110.8 kHz BW, 34mW
- MEDIAN mode, FIR filter
- Up to 128 kSPS, 55.4 kHz BW, 20mW
- Low power mode, FIR filter
- Up to 32 kSPS, 13.85 kHz BW, 7mW
Embedded analog functionality will greatly reduce the design burden over the entire range of applications the AD7768-1 is employed in. The precharge buffer on each analog input decreases analog input current compared to competitive offerings, simplifying the task of an external amplifier to drive the analog input.
There is a full buffer input on the reference. This will allow for vastly reduced input current providing a high impedance input for the external reference device or in buffering any reference sense resistor scenarios that can be used in ratio-metric measurements.
The device operates with a 5 V AVDD1 supply, a 2.2 V to 5 V AVDD2 supply, and a 1.8V to 3.3 V IOVDD supply. In low power mode, the full device can run from a single 3.3V rail.
The device requires an external reference; the absolute input reference voltage range is 1 V to AVDD1 - AVSS.
The specified operating temperature range is -40°C to +125°C. The device is housed in a 4 mm × 5 mm 28-lead LFCSP and a 24-lead TSSOP
No-OS Driver Description
Functions Declarations
| Function | Description |
|---|---|
int32_t ad77681_setup(ad77681_dev **device, ad77681_init_param init_param); | Initialize the device. |
int32_t ad77681_soft_reset(ad77681_dev *dev); | Device reset over SPI. |
int32_t ad77681_set_status_bit(ad77681_dev *dev, bool status_bit); | Activates CRC on all SPI transactions and Selects CRC method as XOR or 8-bit polynomial. |
resources/eval/user-guides/ad7768-1.1499069723.txt.gz · Last modified: 03 Jul 2017 10:15 by Stefan Popa