Overview
The AD7730BN, produced by Analog Devices Inc., is a complete analog front end designed specifically for weigh-scale and pressure measurement applications. This device accepts low-level signals directly from a transducer and outputs a serial digital word. It features a proprietary programmable gain front end based around an analog modulator, which is processed by a low pass programmable digital filter. This allows for the adjustment of filter cutoff, output rate, and settling time. The AD7730BN operates from a single +5 V supply and is compatible with microcontrollers and digital signal processors through its serial interface, which can be configured for three-wire operation.
Key Specifications
| Parameter | Value | Conditions/Comments |
|---|---|---|
| Resolution | 24 Bits | Minimum output noise and update rates |
| Integral Nonlinearity | 18 ppm of FSR max | |
| Offset Error | See Note 3 in datasheet | |
| Offset Drift | < 5 nV/°C | |
| Gain Drift | < 2 ppm/°C | |
| Analog Input Ranges (Unipolar) | 0 mV to +10 mV, +20 mV, +40 mV, +80 mV | |
| Analog Input Ranges (Bipolar) | ±10 mV, ±20 mV, ±40 mV, ±80 mV | |
| Supply Voltage | +5 V | |
| Package Options | 24-pin plastic DIP, 24-lead SOIC, 24-lead TSSOP | |
| Clock Frequency | fCLK IN = 4.9152 MHz |
Key Features
- Two-channel programmable gain front end with on-chip DAC for offset/TARE removal.
- FASTStep™ mode for AC or DC excitation.
- Single supply operation with a +5 V supply.
- Serial interface compatible with microcontrollers and digital signal processors, configurable for three-wire operation.
- Self-calibration and system calibration options.
- Low offset drift of less than 5 nV/°C and gain drift of less than 2 ppm/°C.
- On-chip 6-bit DAC for TARE voltage removal.
- Clock signals for synchronizing AC excitation of the bridge.
Applications
- Weigh scales: The AD7730BN is designed to handle the low-level signals from load cells in weigh-scale applications.
- Pressure measurement: It is also suitable for pressure measurement applications, accepting signals directly from pressure transducers.
Q & A
- What is the primary application of the AD7730BN?
The AD7730BN is primarily used for weigh-scale and pressure measurement applications.
- What is the resolution of the AD7730BN?
The AD7730BN has a resolution of 24 bits).
- What are the analog input ranges supported by the AD7730BN?
The device supports both unipolar and bipolar analog input ranges: 0 mV to ±10 mV, +20 mV, +40 mV, and +80 mV for unipolar, and ±10 mV, ±20 mV, ±40 mV, and ±80 mV for bipolar).
- What is the supply voltage for the AD7730BN?
The AD7730BN operates from a single +5 V supply).
- What types of packages are available for the AD7730BN?
The device is available in 24-pin plastic DIP, 24-lead SOIC, and 24-lead TSSOP packages).
- Does the AD7730BN support self-calibration?
Yes, the AD7730BN supports self-calibration and system calibration options).
- What is the offset drift and gain drift of the AD7730BN?
The AD7730BN has an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C).
- How is the serial interface of the AD7730BN configured?
The serial interface can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors).
- What is the purpose of the on-chip 6-bit DAC in the AD7730BN?
The on-chip 6-bit DAC is used for the removal of TARE voltages).
- Does the AD7730BN provide clock signals for AC excitation?
Yes, the AD7730BN provides clock signals for synchronizing AC excitation of the bridge).
