AS8510
D a t a A cq u is i t io n D ev ic e f o r B a t t e r y S e n s o r s
1 General Description
The AS8510 is a virtually offset free, low noise, two channel
measurement device. It is tailored to accurately measure battery
current from mA range up to kA range in conjunction with a 100 µΩ
shunt resistor in series with the battery rail. Through the second
measurement channel it enables capture of, either battery voltage
synchronous with the current measurement, or, measure the analog
output of an internal or external temperature sensor. Both channels
are matched and can either measure small signals up to ±160 mV
versus ground, through programmable gain amplifier or larger
signals in the 0 to 1V range without the amplifier.
After analog to digital conversion and digital filtering, the resulting
16-bit digital words are accessible through 4-wire standard serial
interface.The device includes a number of additional features
explained in the next section.
Option for multiplexing either one differential input, or two single
ended inputs or the internal temperature sensor on one channel
Programmable current source for external temperature sensor
connectable to any of the inputs
High precision and high stability 1.2V reference voltage source
Digital signal processing with filter options for both channels
Four operating modes providing
- Continuous data acquisition (or)
- Periodic single-shot acquisition, (or)
- Continuous acquisition on threshold crossing of programmed
current levels (or)
- A combination of the above
On chip high-precision 4MHz RC oscillator or option for external
clock
-40ºC to +125ºC ambient operation
AEC - Q100 automotive qualified
Internal chip ID for full traceability
2 Key Features
3.3V supply voltage
Two High resolution 16 bit
Σ−Δ
A/D converters
SSOP-20 pin package
Programmable sampling to enable data throughputs from less
than 1Hz to 8kHz
Zero Offset for both channels
Independent control of data rate on both channels
Precision, low noise, programmable gain amplifiers for both
3 Applications
The AS8510 is ideal for shunt based batteries sensor. For high-side
current sensing, the input signal may be conditioned using
ams
device AS8525 before applying to this device.
channels with gains 5, 25, 40, 100 to support wide dynamic
ranges.
Figure 1. AS8510 Block Diagram
AVDD
Internal Temperature Sensor
Prog-Cur
Source
MUX and
Chopper
PGA
16-bit Sigma-Delta ADC
REF
Bandgap Reference
DVDD
Oscillators
ETR
ETS
VBAT_IN
VBAT_GND
MEN
FIR / MA
AS8510
RSHH
RSHL
Chopper
PGA
16-bit Sigma-Delta ADC
CHOP_CLK
INT
CLK
Analog Common Mode
Serial Interface
AVSS
VCM
SCLK CS
SDI
SDO
DVSS
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AS8510
Datasheet - C o n t e n t s
Contents
1 General Description
...................................................................................................................................................................... 1
2 Key Features.................................................................................................................................................................................
1
3 Applications...................................................................................................................................................................................
1
4 Pin Assignments
........................................................................................................................................................................... 4
4.1 Pin Descriptions........................................................................................................................................................................................
4
5 Absolute Maximum Ratings
.......................................................................................................................................................... 6
6 Electrical Characteristics...............................................................................................................................................................
7
6.1 Operating Conditions................................................................................................................................................................................
7
6.2 DC/AC Characteristics for Digital Inputs and Outputs
.............................................................................................................................. 7
6.3 Detailed System and Block Specifications
............................................................................................................................................... 9
6.3.1 Electrical System Specifications .................................................................................................................................................. 9
6.4 Current Measurement Ranges (across 100µOhm shunt resistor)
........................................................................................................... 9
6.4.1 Differential Input Amplifier for Current Channel .......................................................................................................................... 10
6.4.2 Differential Input Amplifier for Voltage Channel.......................................................................................................................... 11
6.4.3 Sigma Delta Analog to Digital Converter .................................................................................................................................... 12
6.4.4 Bandgap Reference Voltage....................................................................................................................................................... 12
6.4.5 Internal (Programmable) Current Source for External Temperature Measurement ................................................................... 13
6.4.6 CMREF Circuit (VCM) ................................................................................................................................................................ 14
6.4.7 Internal AVDD Power-on Reset .................................................................................................................................................. 14
6.4.8 Internal DVDD Power-on Reset.................................................................................................................................................. 14
6.4.9 Low Speed Oscillator.................................................................................................................................................................. 14
6.4.10 High Speed Oscillator ............................................................................................................................................................... 15
6.4.11 External Clock........................................................................................................................................................................... 15
6.4.12 Internal Temperature Sensor.................................................................................................................................................... 15
6.5 System Specifications
............................................................................................................................................................................ 15
7 Detailed Description....................................................................................................................................................................
18
7.1 Current Measurement Channel
.............................................................................................................................................................. 18
7.2 Voltage/Temperature Measurement Channel
......................................................................................................................................... 18
7.3 Digital Implementation of Measurement Path.........................................................................................................................................
19
7.4 Modes of Operation
................................................................................................................................................................................ 19
7.4.1
7.4.2
7.4.3
7.4.4
Normal Mode 1 (NOM1) ............................................................................................................................................................. 21
Normal Mode 2 (NOM2) ............................................................................................................................................................. 21
Standby Mode1 (SBM1) ............................................................................................................................................................. 22
Standby Mode2 (SBM2) ............................................................................................................................................................. 23
7.5 Reference-Voltage..................................................................................................................................................................................
23
7.6 Oscillators...............................................................................................................................................................................................
23
7.7 Power-On Reset
..................................................................................................................................................................................... 23
7.8 4-Wire Serial Port Interface
.................................................................................................................................................................... 24
7.8.1
7.8.2
7.8.3
7.8.4
7.8.5
SPI Frame................................................................................................................................................................................... 24
Write Command.......................................................................................................................................................................... 25
Read Command.......................................................................................................................................................................... 26
Timing ......................................................................................................................................................................................... 27
SPI Interface Timing ................................................................................................................................................................... 28
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AS8510
Datasheet - C o n t e n t s
7.9 Control Register......................................................................................................................................................................................
29
7.9.1
7.9.2
7.9.3
7.9.4
7.9.5
7.9.6
Standby Mode - Power Consumption ......................................................................................................................................... 40
Initialization Sequence at Power ON .......................................................................................................................................... 40
Soft-reset of Device Using Bit D[7] of Reset Register 0x09........................................................................................................ 41
Soft-reset of the Measurement Path Using Bit D[7] of Reset Register 0x09 .............................................................................. 42
Reconfiguring Gain Setting of PGA ........................................................................................................................................... 42
Configuring the Device During Normal Mode ............................................................................................................................. 43
7.10 Low Side Current Measurement Application
........................................................................................................................................ 43
8 Package Drawings and Markings
............................................................................................................................................... 44
8.1 Recommended PCB Footprint................................................................................................................................................................
45
9 Ordering Information...................................................................................................................................................................
47
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AS8510
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
RSHH
RSHL
REF
VCM
AVDD
AVSS
ETR
ETS
VBAT_IN
VBAT_GND
1
2
20
19
INT
CLK
SDI
MEN
CHOP_CLK
DVDD
DVSS
SDO
SCLK
CS
3
4
18
17
5
6
7
8
9
10
AS8510
16
15
14
13
12
11
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
Pin Name
RSHH
RSHL
REF
Analog output
VCM
AVDD
AVSS
ETR
ETS
VBAT_IN
VBAT_GND
CS
SCLK
SDO
Digital input
Digital output
Analog input
Supply pad
Pin Type
Analog input
Description
Positive Differential input for current channel
Negative differential input for current channel
Internal reference voltage to sigma-delta ADC; connect 100nF to
AVSS from this pin.
Common Mode voltage to the internal measurement path;
connect 100nF to AVSS from this pin.
+3.3V Analog Power-supply
0V Power-supply analog
Voltage channel single ended input
Battery voltage (high) input
Battery voltage (low) input
Digital input with pull-up Chip select with an internal pull-up resistor (SPI Interface)
Clock signal (SPI Interface)
Serial Data Input (SPI Interface)
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AS8510
Datasheet - P i n A s s i g n m e n t s
Table 1. Pin Descriptions
Pin Number
14
15
Pin Name
DVSS
DVDD
Pin Type
Supply pad
0V Digital Ground
+3.3V Digital Supply
Chop Clock used in High side measurements to synchronize
external chopper.
(As an example, when AS8525 is used to condition the input
signal to the input range of AS8510, the chop clock is used by
AS8525.)
Digital output issued during the Standby Mode (SBM) to signal
the short duration of data sampling. This signal is useful in the
case of a High Side Measurement application.
(For example: This signal is used by AS8525 device to wake-up
and enable the measurement path.)
Data signal (SPI Interface)
By default this pin is the internal clock output which can be used
by a Microcontroller. The internal clock may also be disabled as
an output by programming Register 08. To use an external Clock,
Register 08 has to be programmed.
Active High Interrupt to indicate data is ready
Description
16
CHOP_CLK
Digital output
17
MEN
18
19
20
SDI
CLK
INT
Digital input
Digital I/O
Digital output
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