AS5145H/AS5145A/
AS5145B
12-Bit Programmable Magnetic Rotary
Encoder
General Description
The AS5145 is a contactless magnetic rotary encoder for
accurate angular measurement over a full turn of 360 degrees.
It is a system-on-chip, combining integrated Hall elements,
analog front end and digital signal processing in a single device.
To measure the angle, only a simple two-pole magnet, rotating
over the center of the chip, is required. The magnet can be
placed above or below the IC.
The absolute angle measurement provides instant indication of
the magnet’s angular position with a resolution of
0.0879º = 4096 positions per revolution. This digital data is
available as a serial bit stream and as a PWM signal.
An internal voltage regulator allows the AS5145 to operate at
either 3.3V or 5V supplies.
Ordering Information
and
Content Guide
appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS5145H/AS5145A/AS5145B,
12-Bit Programmable Magnetic Rotary Encoder are listed
below:
Figure 1:
Added Value of Using AS5145
Benefits
•
Highest reliability and durability
•
Simple programming
Features
•
Contactless high resolution rotational position encoding
over a full turn of 360 degrees
•
Simple user-programmable zero position and settings
•
Serial communication interface (SSI)
•
10-bit pulse width modulated (PWM) output
•
Quadrature A/B and Index output signal
•
Rational speeds up to 30,000 rpm
•
Failure detection mode for magnet placement monitoring
and loss of power supply
•
Serial read-out of multiple interconnected AS5145 devices
using Daisy Chain mode
•
Multiple interfaces
•
Ideal for motor applications
•
Failure diagnostics
•
Easy setup
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B −
General Description
Benefits
•
Great flexibility at a huge application area
•
Fully automotive qualified
•
Small form factor
•
Robust environmental tolerance
Features
•
Detects movement of magnet in Z-axis (Red-Yellow-Green
indicator)
•
AEC-Q100, grade 0
•
SSOP 16 (5.3mm x 6.2mm)
•
Wide temperature range: -40°C to 150°C
Applications
The device is ideal for industrial applications like contactless
rotary position sensing and robotics; automotive applications
like steering wheel position sensing, transmission gearbox
encoder, head light position control, torque sensing, valve
position sensing and replacement of high end potentiometers.
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
AS5145 Automotive Rotary Encoder IC
VDD3V3
MagINCn
MagDECn
PWM
Interface
Sin
Ang
VDD5V
LDO 3.3V
PWM
Hall Array
&
Frontend
Amplifier
Cos
DSP
Mag
Absolute
Interface
(SSI)
DO
CSn
CLK
OTP
Register
PDIO
Incremental
Interface
DTEST1_A
DTEST2_B
Mux
Mode_Index
AS5145
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AS5145H/AS5145A/AS5145B −
Pin Assignment
Pin Assignment
Figure 3:
Pin Diagram (Top View)
MagINCn
MagDECn
DTest1_A
DTest2_B
NC
Mode_Index
VSS
PDIO
1
2
3
16
15
14
VDD5V
VDD3V3
NC
NC
PWM
CSn
CLK
DO
AS5145
4
5
6
7
8
13
12
11
10
9
Pin Description
The following SSOP16 shows the description of each pin of the
standard SSOP16 package (Shrink Small Outline Package, 16
leads, body size: 5.3mm x 6.2mmm; (see
Figure 3).
Figure 4:
Pin Description
Pin Name
Pin
Number
1
Pin Type
Description
Magnet Field Magnitude Increase.
Active low.
Indicates a distance reduction between the
magnet and the device surface. (see
Figure 15)
Magnet Field Magnitude Decrease.
Active low.
Indicates a distance increase between the device
and the magnet. (see
Figure 15)
Test output in default mode
MagINCn
Digital output open
drain
MagDECn
DTest1_A
DTest2_B
NC
Mode_Index
VSS
2
3
Digital output
4
5
6
7
-
Digital input/output
pull-down
Supply pin
Test output in default mode
Must be left unconnected
Select between slow (open, low: VSS) and fast
(high) mode. Internal pull-down resistor (10kΩ).
Negative supply voltage (GND)
ams Datasheet
[v2-00] 2016-Feb-05
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AS5145H/AS5145A/AS5145B −
Pin Assignment
Pin Name
Pin
Number
Pin Type
Description
OTP Programming Input and Data Input for
Daisy Chain Mode.
Pin has an internal pull-down
resistor (74kΩ). Connect this pin to VSS if
programming is not required.
Data Output
of Synchronous Serial Interface
Clock Input
of Synchronous Serial Interface;
Schmitt-Trigger input
Chip Select.
Active low. Schmitt-Trigger input,
internal pull-up resistor (50kΩ)
Pulse Width Modulation
Must be left unconnected
Must be left unconnected
3V-Regulator output, internally regulated from
VDD5V. Connect to VDD5V for 3V supply voltage.
Do not load externally.
Positive supply voltage, 3.0V to 5.5V
PDIO
8
Digital input
pull-down
Digital output/
tri-state
Digital input,
Schmitt-Trigger input
Digital input
pull-down,
Schmitt-Trigger input
Digital output
-
-
Supply pin
Supply pin
DO
CLK
9
10
CSn
PWM
NC
NC
VDD3V3
VDD5V
11
12
13
14
15
16
Pin 1 and 2 are the magnetic field change indicators, MagINCn
and MagDECn (magnetic field strength increase or decrease
through variation of the distance between the magnet and the
device). These outputs can be used to detect the valid magnetic
field range. Furthermore those indicators can also be used for
contactless push-button functionality.
Pin 3 and 4 are multi function pins for sync mode, sine/cosine
mode and incremental mode.
Pin 6 Mode_Index allows switching between filtered (slow) and
unfiltered (fast mode). In incremental mode, the pin changes
from input to output and provides the index pulse information.
A change of the mode during operation is not allowed. The
setup must be constant during power up and during operation.
Pins 7, 15, and 16 are supply pins, pins 5, 13, and 14 are for
internal use and must not be connected.
Pin 8 (PDIO) is used to program the zero-position into the
OTP(see
page 27).
This pin is also used as digital input to shift
serial data through the device in daisy chain configuration, (see
page 18).
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AS5145H/AS5145A/AS5145B −
Pin Assignment
Pin 11 Chip Select (CSn; active low) selects a device within a
network of AS5145 encoders and initiates serial data transfer.
A logic high at CSn puts the data output pin (DO) to tri-state
and terminates serial data transfer. This pin is also used for
alignment mode (see
Alignment Mode)
and programming
mode (see
Programming the AS5145).
Pin 12 allows a single wire output of the 12-bit absolute position
value. The value is encoded into a pulse width modulated signal
with 1μs pulse width per step (1μs to 4096μs over a full turn).
By using an external low pass filter, the digital PWM signal is
converted into an analog voltage, e.g. for making a direct
replacement of potentiometers possible.
ams Datasheet
[v2-00] 2016-Feb-05
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