AS8500_1 AMSCO [austriamicrosystems AG], AS8500_1 Datasheet

AS8500_1

Manufacturer Part Number

AS8500_1

Description

Universal multi pupose data aquisition system

Manufacturer

AMSCO [austriamicrosystems AG]

Datasheet

1.AS8500_1.pdf (41 pages)

Current page: 1 of 41
Download datasheet (591Kb)

1.1

Revision 1.2, 08-Junel-06

The AS8500 is a complete, low power data acquisition system

for very small signals (i.e. voltages from shunt resistors,

thermocouples) that operates on a single 5 V power supply. The

chip powers up with a set of default conditions at which time it

can be operated as a read-only-converter. Reprogramming is at

any time possible by just writing into two internal registers via

the serial interface.

The AS8500 has four ground refering inputs which can be

switched separately to the internal PGA. Two input channels can

also be operated as a fully differential ground free input. The

system can measure both positive and negative input signals.

The PGA amplification ranges from 6 to 100 which enables the

system to measure signals from 7mV to 120 mV full scale range

with high accuracy, linearity and speed.

The chip contains a high precision bandgap reference and an

active offset compensation that makes the system offset free

(better than 0,5 !V) and the offset-TC value negligible. The built-

in programmable digital filter allows an effective noise

suppression if the high speed is not necessary in the application.

The input noise density is only 35 nV / Hz and due to

AS8500

Universal multi pupose data aquisition system

16 bits resolution

differential inputs

Single + 5V supply

Low power 15 mW

SOIC16 package

16 kHz maximum sampling frequency

internal temperature measurement

internal reference

programmable current sources

digital comparator

active wake-up

PGA gains 6, 24, 50, 100

Zero offset

Zero offset TC

Extremely low noise

Internal oscillator with comparator for active wake up

3-wire serial interface, !P compatible

temperature range – 40 to + 125 °C

battery management for automotive systems

power management

mV/µ V-meter

thermocouple temperature measurement

RTD precision temperature measurement

high-precision voltage and current measurement

Features

Applications

General description

www.austriamicrosystems.com

ETR

ETS

RSHH

VBAT

RSHL

the high internal chopping frequency the system is free of 1/f-noise down

to DC.The 0-10 Hz noise is typical below 1 µ V i.e. as good or better than

any other available chopper amplifier.

For high speed synchronous measurements the chip can run in an

automatic switching mode between two input channels with pre-

programmed parameter sets.

The circuit has been optimised for the application in battery management

systems in automotive systems. As a front end data acquisition system it

allows an high quality measurement of current, voltage and temperature

of the battery.

With a high quality 100 !" resistor the system can handle the starter

current of up to 1500 A, a continuous current of # 300 A as well as the

very low idle current of a few mA in the standby mode.

For external temperature measurement the chip can use a wide variety of

different temperature sensors such as RTD, PTC, NTC, thermocouples or

even diodes or transistors. A built-in programmable current source can be

switched to any input and activate these sensors without the need of

other external components.

The measurement of the chip temperature with the integrated internal

temperature sensor allows in addition the temperature compensation of

sensitive parameters which increases the total accuracy considerably.

The flexibility of the system is further increased by a digital comparator

that can be assigned to any measured property

(current, voltage, temperature) and an active wake-up in the sleep-mode.

All analog input-terminals can be checked for wire break via the SDI-

interface.

Figure 1: Functional Block Diagram

INTERNAL TEMPERATURE

PROTECTION

INPUT MUX

CHOPPER

SOURCES

CURRENT

16 BIT - CONVERTER

LEVEL SHIFT

SERIAL INTERFACE / CONTROL REGISTERS

REF

BUF

PGA

and

SCLK

REFERENCE

1.26 V

SDAT

AGND

Data Sheet

COMPARATOR

CALIBRATION

CONTROLLER

DATA SHEET

VDDA

INT. CLOCK

INTN

FILTER

TIMER

DATA

DSP

VSSA

Page 1 of 41

CLK

EZPRG

VDDD

VSSD

Related parts for AS8500_1

AS8500_1 Summary of contents

Page 1

AS8500 2 Universal multi pupose data aquisition system 1 Features 16 bits resolution differential inputs Single + 5V supply Low power 15 mW SOIC16 package 16 kHz maximum sampling frequency internal temperature measurement internal reference programmable current sources digital ...

Page 2

FEATURES ........................................................................................................................................................................................ 1 2 APPLICATIONS................................................................................................................................................................................. 1 3 GENERAL DESCRIPTION ................................................................................................................................................................ 1 4 PIN FUNCTION DESCRIPTION FOR SOIC 16 PACKAGE.............................................................................................................. 3 5 ABSOLUTE MAXIMUM RATINGS.................................................................................................................................................... 4 6 ELECTRICAL CHARACTERISTICS ................................................................................................................................................. 5 7 FUNCTIONAL DESCRIPTION .......................................................................................................................................................... 9 7 ........................................................................................................................................................................... ...

Page 3

PIN function description for SOIC 16 package PIN Name 1 RSHL anlalog input from shunt resistor low side 2 RSHH anlalog input from shunt resistor high side 3 ETS analog input with reference to RSHL analog input for differential ...

Page 4

Absolute Maximum Ratings Stress beyond those listed under “Absolute Maximum Ratings“ may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at these or any other conditions beyond those indicated under “Operating ...

Page 5

Electrical characteristics VDDA=5V +/-0.1 V, fclk=8.192 MHz, chopping ratio MM=4 (see 7.5.3), oversampling frequency=2.048 MHz, oversampling ratio=128 temperature range : -40 to 125°C if not otherwise noted symbol parameter input characteristics for gain 1 the input signal is connected ...

Page 6

Electrical characteristics (continued) VDDA=5V +/-0.1 V, fclk=8.192 MHz, chopping ratio MM=4 (see 7.5.3), oversampling frequency=2.048 MHz, oversampling ratio=128 temperature range : -40 to 125°C if not otherwise noted symbol parameter cal_err calibration error for 30 000 digits output at full ...

Page 7

Electrical characteristics (continued) VDDA=5V +/-0.1 V, fclk=8.192 MHz, chopping ratio MM=4 (see 7.5.3), oversampling frequency=2.048 MHz, oversampling ratio =128 symbol parameter data conversion RES resolution Vref reference voltage Vref_TC temperature coefficient of Vref Vref_Ri internal resistance of Vref fovs clock ...

Page 8

Electrical characteristics (continued) VDDA=5V +/-0.1 V, fclk=8.192 MHz, chopping ratio MM=4 (see 7.5.3), oversampling frequency=2.048 MHz, oversampling ratio=128 temperature range : -40 to 125°C if not otherwise noted symbol parameter programmable current source Icurr_ON current level I_steps current steps TC_CS ...

Page 9

Functional Description 7.1 Power on Reset The power on reset is iniciated during each power up of the ASSP and can be triggered purpously by reducing the analog supply voltage (VDDA value lower than Vporlo for a ...

Page 10

M 6 ETR M 8 ETS M 14 VBAT RSHH RSHL AUXILIARY CURRENT SOURCE M 13 Figure 3: Multiplexer 7.2.1 Reference voltage The ASSP contains a highly sophisticated precision reference voltage. Its ...

Page 11

Writing into subregister TRIMBV of TRR changes the absolute value linearly by 5.1 mV per digit as shown in the following graph and described in full detail in 7.5.7 1,36 1,32 1,28 1,24 1,20 1, Trimming the TC ...

Page 12

Current sources The AS8500 contains several current sources which can be used for checking all input lines for wire brake, to control external circuitry or to activate external sensors. Main current source The main current source can be digitally ...

Page 13

Internal temperature sensor The ASSP contains a high sensitive precision temperature sensor which can be used at any time. The sensor supplies a very linear voltage with temperature. The voltage can be measured using the internal circuitry with gain ...

Page 14

The absolute input-output calibration of the gain ranges can be done that way that for a given input voltage 30 000 digits at the output are produced: Table 7.2.2 gain input/mV 1 720 6 120 100 ...

Page 15

Modes of operation The AS8500 can run in different operation modes, which are selected and activated via the serial interface. Detailed description: Mode 0: MZL In power-on reset sequence, which is initiated by the on-chip power-on reset circuit whenever ...

Page 16

AS8500 - Data Sheet Modes of operation, register OPM Mode Name 0 MZL Power on, loading from Zener-Zap memory 1 MMS Single measurement 2 MMD Double measurement (A,B,A,B …) 3 MWU Wake-up 4 MAM Alarm 5 MZP Zener program/read 6 ...

Page 17

AS8500 - Data Sheet 7.5.1 OPM operation mode register ( 4 bits ) no. Bit mo3 mo2 0 default 0 1) This register has been described in detail under 7.4 7.5.2 CRG general configuration register ( 28 bits ) no. ...

Page 18

AS8500 - Data Sheet Current source setting bits (5 bits) Nr. Current [uA … … 31 248 subregister CRV: Voltage configuration (4 bits ) Nr. Bits 3 0 CRV bit ...

Page 19

AS8500 - Data Sheet subregister CRU: calibration constant selection for voltage path ( 3 bits) in registers CRA,CRB Nr. Calibration const CAU0 1 CAU1 2 CAU2 3 CAU3 4 CAU4 5 CAU5 6 1548 7 1548 subregister CRM: ...

Page 20

AS8500 - Data Sheet subregister MM: chopping ratio bit, Registers CRA, CRB Nr Notes: 1) For c=0 and d=0 , chopping and dechopping is switched off and every cycle is active regardless of ...

Page 21

AS8500 - Data Sheet 7.5.5 ZZR Zener-Zap register (188 bits ): For the AS8500 the zener zap registers are set to a predefined default value exception the TRIMA bits in the ZTR subregister is factory adjusted for minimum ...

Page 22

AS8500 - Data Sheet Calibration constant selection truth table Nr. cu2 cu1 cu0 ...

Page 23

AS8500 - Data Sheet 7.5.6 CAR calibration register ( 110 bits ) The aim of the calibration register is to hold the calibration constants that are used by the internal DSP for the correction of each measurement (for the factory ...

Page 24

AS8500 - Data Sheet subregister TRIMA The offset of the PGA is factory trimmed to a mimimum absolute value to guarantee the full dynamic range with all gain settings. change of amplifier offset with TRIMA bits Nr. trimas trima3 0 ...

Page 25

AS8500 - Data Sheet TRIMBV=16+int(-(Uam-1.232)/0.0051) for Uam below the ideal value. subregister TRIMBTC change of reference voltage Uo and TC-value with TRIMBTC bits Nr. trimbtcs trimbtc3 trimbtc2 ...

Page 26

AS8500 - Data Sheet 7.5.8 THR alarm (Wake-up) threshold register ( 17 bits ) Nr. MR16 MR15 MR14 0 A/B s Msb default Notes: All measurements are performed in channel A therefore MR16 must be set to ...

Page 27

AS8500 - Data Sheet The trailing edge of INTN signals the start of a new measurement. INTN available i-2 results on SDI Figure 5: INTN pin in modes 1 and 2 The determination of Tcnv and Tres from the parameter ...

Page 28

AS8500 - Data Sheet The slave unit drives the sdat signal only in master-read data condition. In all other cases the slave sdat pin is in high-impedance state. During data transfer in read condition the internal AD-conversion in continuing but ...

Page 29

AS8500 - Data Sheet 7 TRR 8 THR 8.5 SDI bus timing Timing definitions for SDI bus are based on software-implemented master unit protocol MDE sclk (uP) master sdat (uP) slave sdat (ASIC) strobe ASSP Figure 8: SDI Bus timing ...

Page 30

AS8500 - Data Sheet SDI bus timing Nr. PARAMETER 0 SCLK pulse width 1 SCLK low 2 Master SDAT exception after SCLK 3 Master SDAT valid before/after SCLK 4 Slave SDAT not valid after SCLK 5 Master 3-state ON/OFF 6 ...

Page 31

AS8500 - Data Sheet Cell index 8 trimc0 Purpose trimc1 ZTR ZZR field ZTR 178 ZZR bit 179 Cell index 16 17 trimbv2 Purpose trimbv3 ZTR ZZR field ZTR 170 ZZR bit 171 Cell index 24 25 cgi1_10 Purpose trimbtc0 ...

Page 32

AS8500 - Data Sheet Cell index 72 73 Purpose cau0_7 cau0_6 ZZR field ZCL ZCL ZZR bit 115 114 Cell index 80 81 cau1_9 Purpose cau1_10 ZZR field ZCL ZCL ZZR bit 107 106 Cell index 88 89 Purpose cau1_2 ...

Page 33

AS8500 - Data Sheet Cell index 136 137 Purpose tcu1_7 tcu1_6 ZZR field ZTC ZTC ZZR bit 51 50 Cell index 144 145 Purpose tcu0_8 tcu0_7 ZZR field ZTC ZTC ZZR bit 43 42 Cell index 152 153 Purpose tcu0_0 ...

Page 34

AS8500 - Data Sheet 8.6.2 Stored ZZR-register mapping ZZR subreg bitno in subregister 10 9 msb ZLO ZTR TRIMC TRIMA TRIMBV TRIMBTC ZCL CGI1 1 1 CGI2 1 1 CGI3 1 1 CGI4 0 0 CAU0 1 1 CAU1 1 ...

Page 35

General application hints Since the AS8500 is optimised for low voltage applications extreme care should be taken that the signal is not disturbed by influences like bad ground reference, external noise pick-up, thermal EMFs generated at the transition of ...

Page 36

The total noise voltage generated at a given frequency resp given frequency band (BW) is given by: Un= En*sqr(BW) This square root dependence can be seen very nicely in fig. 9.10. The typical square-root shaped dependence is found ...

Page 37

Typical performance characteristics Revision 1.2, 08-Junel-06 41 www.austriamicrosystems.com Page 37 of ...

Page 38

Revision 1.2, 08-Junel-06 41 www.austriamicrosystems.com Page 38 of ...

Page 39

Package Dimensions Thermal Resistance junction / ambient.: 66 K/W (typ.) in still air 11 Revision History Revision Date 1.0 Feb.10, 2006 1.1 March 23, 2006 1.2 June 2006 12 Ordering Information Delivery: Tape and Reel (1 reel ...

Page 40

Contact 13.1 Headquarters austriamicrosystems AG A 8141 Schloss Premstätten, Austria Phone: +43 3136 500 0 Fax: +43 3136 525 01 industry.medical@austriamicrosystems.com www.austriamicrosystems.com 13.2 Sales Offices austriamicrosystems Germany GmbH Tegernseer Landstrasse 85 D-81539 München, Germany Phone: + ...

Page 41

Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent identification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied description regarding the information set forth herein or regarding ...

Related keywords

AS8500_1 datasheet
AS8500_1 data sheet
AS8500_1 pdf datasheet
AS8500_1 component
AS8500_1 part
AS8500_1 distributor
AS8500_1 RoHS
AS8500_1 datasheet download