The AS5311 is a contactless high resolution magnetic linear encoder
for accurate linear motion and off-axis rotary sensing with a
resolution down to <0.5µm. It is a system-on-chip, combining
integrated Hall elements, analog front end and digital signal
processing on a single chip, packaged in a small 20-pin TSSOP
package.
A multi-pole magnetic strip or ring with a pole length of 1.0mm is
required to sense the rotational or linear motion. The magnetic strip
is placed above the IC at a distance of typ. 0.3mm.
The absolute measurement provides instant indication of the magnet
position within one pole pair with a resolution of 488nm per step (12-
bit over 2.0mm). This digital data is available as a serial bit stream
and as a PWM signal.
Furthermore, an incremental output is available with a resolution of
1.95µm per step. An index pulse is generated once for every pole
pair (once per 2.0mm).The travelling speed in incremental mode is
up to 650mm/second.
An internal voltage regulator allows the AS5311 to operate at either
3.3 V or 5 V supplies. Depending on the application the AS5311
accepts multi-pole strip magnets as well as multi-pole ring magnets,
both radial and axial magnetized (see
Figure 1
and
Figure 3).
Figure 1. AS5311 Block Diagram
The AS5311 is available in a PB-free TSSOP-20 package and
qualified for an ambient temperature range from -40°C to +125°C.
2 Key Features
Two 12-bit digital absolute outputs:
- Serial interface and
- Pulse width modulated (PWM) output
Incremental output with Index
“Red-Yellow-Green” indicators monitor magnet placement over
the chip
3 Applications
Micro-Actuator feedback
Servo drive feedback
Robotics
Replacement of optical encoders
VDD3V3
MagINCn
MagDECn
VDD5V
LDO 3.3V
PWM
Interface
Sin
Ang
PWM
Linear Hall
Array
&
Frontend
Amplifier
Cos
DSP
Mag
Absolute
Interface
(SSI)
DO
CSn
CLK
OTP
Register
Programming
Parameters
Incremental
Interface
A
B
Index
Prog
AS5311
www.ams.com/AS5311
Revision 1.13
1 - 32
AS5311
Datasheet - C o n t e n t s
Contents
1 General Description ..................................................................................................................................................................
5 Absolute Maximum Ratings ......................................................................................................................................................
6.2 DC Characteristics for Digital Inputs and Outputs ................................................................................................................................
6.3 Magnetic Input Specification.................................................................................................................................................................
6.4 Electrical System Specifications...........................................................................................................................................................
7.4.1 Adding a Digital Hysteresis........................................................................................................................................................ 14
7.4.2 Implementing Digital Filtering .................................................................................................................................................... 14
7.5 Z-axis Range Indication (“Red/Yellow/Green” Indicator) ....................................................................................................................
8 Application Information ...........................................................................................................................................................
8.2 Position of the Index Pulse .................................................................................................................................................................
8.3 Mounting the Magnet..........................................................................................................................................................................
8.3.2 Alignment of Multi-pole Magnet and IC...................................................................................................................................... 20
8.3.3 Lateral Stroke of Multi-pole Strip Magnets................................................................................................................................. 20
8.4 Measurement Data Example ..............................................................................................................................................................
8.6 Programming the AS5311 ..................................................................................................................................................................
22
23
25
8.6.1 Zero Position Programming ....................................................................................................................................................... 25
8.6.2 User Selectable Settings ........................................................................................................................................................... 26
9 Package Drawings and Markings ...........................................................................................................................................
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