FEATURES
Conversion of 4 sensor signals of photodiodes
(e.g. RGB/XYZ color plus one blank channel for
compensation of parasitic currents or temperature
conversion) or other sensors with current
signal output
Configurable conversion gain and integration
time supports a very high dynamic range of
1 – 2.68E+08
Up to 16 bit (internal 20 bit) signal resolution
by achievable sensitivity up to 20 fA/LSB –
scaling (by a divider) the internal 20 bit on
16 bit output
Adjustable operation modes like continuous, by
command and externally synchronized (by
given start and start/end signal) measurement
Option: external control of integration time and
reference current (gain)
High linearity of amplifying, no cross talking
High absolute accuracy without additional
sources
High reliability internal reference source generation
Consideration of negative offset
Measurement of current for both polarities
Measurement of integration time
Supply and temperature independent response
Insensitive to 50 Hz/60 Hz external disturbances
16 Bit/400 kHz fast I²C interface with programmable
slave addresses
Very low current consumption in active, in
Power down and Standby mode
Supply voltage 2.7 V to 3.6 V
Temperature range -40°C to 125°C
Deliverable in SMD package and as bare die
APPLICATIONS
Precise conversion of average e.g. integral
photo current for optical sensors and arrays
e.g. UV, VIS, IR) and other sensors with current
output
In combination with ams Sensors Germany’s
color sensors: measurement of lights – chromaticity
coordinates (XYZ CIE 1931, DIN 5033
and similar) or color temperatures to control
and process displays and backlights (e.g. LED,
CCFL)
In combination with ams Sensors Germany’s
color and spectral sensors: measurement of reflective
and/or transmitted light – chromaticity
coordinates (XYZ CIE1931, DIN5033 and similar)
measurement of objects and surfaces for
analyzes, quality management, sorting, etc.
1 GENERAL DESCRIPTION
The ASIC AS89010 is a low noise sensor interface application specific standard product (ASSP) and suitable
for coupling of multi-channel optical sensors or sensors using current output. It converts input currents of
for example photodiodes (both polarities) to a digital output and realizes a continuous or triggered
measurement via current integration. Optional the integration time and sensitivity can be controlled by
external programming to extend the internal functions and parameters. The four signal channels convert
directly and simultaneously the input currents to a digital representation of the measured average. The
channels may be divided into three signal channels and one dummy channel for compensation of parasitic
currents. This ASIC is especially suitable for signal conditioning of photodiodes of array sensors like color
or other optical sensors with maximum of 4 channels per chip1. A configurable conversion gain factor and
integration time support a dynamic range2 of 1 - 2.68E+08 and achieves an accuracy of up to 16 bit signal
resolution with sensitivity up to 20 fA/LSB.
The internal reference generations offers a high reliability. The converter is insensitive to a 50 Hz/60 Hz
external disturbances and was especially designed to accommodate high accuracy at high sensitivity
offering high robustness. Automatic Power down (sleep function) between subsequent measurements offers
operation with very low current c60onsumption. Further, it offers a wide range of reference currents
(1.25 nA to 5 μA), integration times (1 ms to 1 s), synchronized mode and other control modes adjustable
by user programming. The conversion data can be accessed via 16 bit/400 kHz fast I²C Interface with
programmable slave addresses. Measurement of actual integration time for a full triggered measurement
can be performed.
AS89010’s supported operating modes depending on required performance:
▪ CMD Mode – single measurement and conversion (controlled via I²C bus),
▪ CONT Mode - continuous measurement and conversion (periodically recurring measuring cycles)
until “Stop” controlled via I²C bus,
▪ SYN[x] modes - synchronized measurement and conversion:
– [SYNS Mode] synchronization of start,
– [SYND Mode] synchronization of start and stop of measuring cycle on the falling edge of the
SYN pin.
The settings for the input current range and integration time are not affected by alternative modes. Further
the converter supports functions like Power down and Standby. It represents a low power solution and is
also suitable for mobile applications.
Based on the high flexibility the AS89010 is suitable as converter for a width range of multi-channel sensors
with current output. The device achieves a high dynamic range especially in (back) light applications and
in measurements of integral intensity of pulsed light. The combination of ams Sensors Germany’s color
sensors with AS89010 is excellently suited for photometry applications (brightness, color coordinate and/or
color temperature), for determining current values for control of spectrally mixed LED light sources or as
sensors for display and (back)light calibration and mobile devices for light measurement. The sensor signal
IC is available in SMD housing or can be supplied as a bare die.