Data Sheet
NAU7802 24-bit ADC
Nuvoton Confidential - 4 - Revision 1.7
1 GENERAL DESCRIPTION
The Nuvoton NAU7802 is a precision low-power 24-bit analog-to-digital converter (ADC), with an
onboard low-noise programmable gain amplifier (PGA), onboard RC or Crystal oscillator, and a
precision 24-bit sigma-delta (Σ-Δ) analog to digital converter (ADC). The NAU7802 device is capable of
up to 23-bit ENOB (Effective Number Of Bits) performance. This device provides a complete front-end
solution for bridge/sensor measurement such as in weigh scales, strain gauges, and many other high
resolution, low sample rate applications.
The many built-in features enable high performance applications with very low external parts count.
Additionally, both operating current and standby current are very low, and many power management
features are included. These enable powering only those elements of the chip that are needed, and
also, to operate at greatly reduced power if the full 23-bit ENOB performance is not required.
The Programmable Gain Amplifier (PGA) provides selectable gains from 1 to 128. The A/D conversion
is performed with a Sigma-Delta modulator and programmable FIR filter that provides a simultaneous
50Hz and 60Hz notch filter to effectively improve interference immunity. Also, this device provides a
standard 2-wire interface compatible with I2C protocol for simple and straightforward connection to and
interoperation with a wide range of possible host processors.
2 SYSTEM BLOCK DIAGRAM
Control Signal
ADC result
1
0
Internal RC
Oscillator
24- bit ADC
14
24
PGA
Temperature
Sensor
Digital
Interface
OSCS
CRS[2:0]
PGA[1:0]
CHS
VBG XOUTAVDD XIN
SCLK
SDIO
DRDY
VIN2P
VIN1P
VIN1N
VIN2N
AVSS REFP REFN DVSS
LDO
LDO
To serial
Interface
IO Power
2.7V~5.5V Input
digital logic
Bandgap
Reference
VLDO [1:0]
DVDD
To
Analog
Circuit