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db12348e_V3.11_preliminary_2017-07-06

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AS89010

V3.11

3 BLOCK DIAGRAM

The main components of the AS89010 are shown in Figure 2. The input currents are directly converted by

Delta-Sigma to digital converter. The reference current for the A/D converters and optionally the bias

voltage for the photodiodes VPD (see Figure 19) are provided by the internal reference generator10. The

results of the A/D conversion are stored in four 16 bit registers and can be accessed via I²C interface. The

input SYN can be used for an externally triggered start or start and stop of the measurement, the output

READY gives the information of the status of the conversion. The I²C slave address is set by pins A0 and

A1. Separated analog and digital power supply pins are used for noise decoupling.

Figure 2: Block diagram

Reference

Generator

4 x 16 Bit

Register

Control

Register

Integrating A/D

Converter

Control

Unit

I²C

Interface

SCL

SDA

IN0

IN1

IN2

IN3

VPD

VDDA

VSSA

READY

SYN

VDD

VSS

REXT

Clock

Generator

A0

A1

4 PIN ASSIGNMENT

The Pin assignment is shown in the following table.

Table 4: Pin assignment (Analog/Digital)

10 The external resistor REXT directly influences the generating of the reference current for the signal conversion. Therefore, the temper-

ature coefficient of resistance has an important role. The smaller the temperature coefficient and the resistor value tolerance (1% better

than 5%, etc.) result the more accurate the result of the converting.

PIN

TYPE

A/D

DESCRIPTION

VDDA

power

A

analog power supply voltage

VSSA

power

A

analog power supply voltage

VDD

power

D

digital power supply voltage (VDDA = VDD)

VSS

power

D

digital power supply voltage (VSSA = VSS)

IN0, IN1, IN2, IN3

input

A

input current

REXT

input

A

external resistor of 3.3 MΩ

VPD

output

A

photodiodes bias voltage (cathode or anode)

SCL

input

D

I²C clock input

SDA

input /

output

D

I²C data input / output, open drain output stage

SYN

input

D

externally controlled conversion

READY

output

D

conversion status, push pull output stage

A0, A1

input

D

variable I²C slave address