Data Sheet
AEAT-8811-Q24
Magnetic Encoder IC: 10-Bit to 16-Bit Programmable
Angular Magnetic Encoder with No Offset Calibration
Overview
The Broadcom AEAT-8811-Q24 is an angular magnetic
rotary sensor that provides accurate angular measurement
over a full 360 degrees of rotation.
It is a sophisticated system that uses integrated Hall sensor
elements with complex analog and digital signal processing
within a single device.
A simple two-pole magnet generates the necessary
magnetic field by rotating it in perpendicular, placed in
alignment to the center of the device.
The Broadcom AEAT-8811-Q24 is a versatile solution
capable of supporting a broad range of applications with its
robust architecture to measure and deliver both absolute
and incremental signals.
The absolute angle measurement provides an instant
indication of the magnet's angular position with a selectable
and one-time programmable resolution of 10, 12, 14, or
16 bits. When selected, its positioning data is then
represented in its digital form to be assessed through a
standard SSI 3-wire communication protocol. Where
desired, users may also choose to receive its absolute angle
position in PWM-encoded output signals.
The incremental positions are indicated on ABI and UVW
signals with user-configurable CPR 32, 64, 128, 256, 512,
1024, 2048, 4096 and 50, 100, 200, 400, 800, 1000, 2000,
and 4000 of ABI signals and pole pairs from 1 to 8 (2 to 16
poles) for UVW commutation signals. AEAT-8811-Q24
requires no offset calibration programming and operates at
5V supply.
Key Features
5V operation
Selectable 10, 12, 14, or 16 bits of absolute resolution
Incremental output of ABI UVW (32, 64, 128, 256, 512,
1024, 2048, 4096, 50, 100, 200, 400, 800, 1000, 2000,
4000 CPR)
PWM output modes
User-programmable zero position, direction, and index
width
Selectable zero latency mode option
Programmable hysteresis
Available in 2-wire or 3-wire SSI options. Selectable
3-wire SSI option with initial data output at tri-state
mode
Compact QFN-24 leads (5 mm × 5 mm) package
RoHS compliant
No programming required for offset calibration
Specifications
Absolute 10-bit to 16-bit resolution
Incremental output resolutions of 32 to 4096 CPR
UVW output of 1 to 8 pole pairs
Wide operating temperature: –40°C to 125°C
Applications
Brushless DC motor and stepper motor
Resolver and potentiometer replacement
Industrial automation and robotics
Industrial sewing machine and textile equipment
Broadcom
AEAT-8811-Q24-DS100
February 21, 2020
AEAT-8811-Q24
Data Sheet
Magnetic Encoder IC: 10-Bit to 16-Bit Programmable Angular Magnetic Encoder with No
Offset Calibration
NOTE:
This product is not specifically designed or
manufactured for use in any specific device.
Customers are solely responsible for determining
the suitability of this product for its intended
application and are solely liable for all loss,
damage, expense, or liability in connection with
such use.
Figure 1: ABI Signals of AEAT-8811-Q24
Definition
Electrical Degree (°e):
CPR × 360 electrical degrees =
360 mechanical degrees.
Cycle (C):
One cycle of the incremental signal is 360
mechanical degrees/resolution and is equal to 360 electrical
degrees (°e).
Pulse Width (P):
The number of electrical degrees that an
output is high during one cycle, nominally 180°e or one-half
of a cycle.
State Width (S):
The number of electrical degrees between
a transition in the output of channel A and the neighboring
transition in the output of channel B. There are four states
per cycle, each nominally 90°e.
Phase (Φ):
The number of electrical degrees between the
center of the high state on channel A and the center of the
high state on channel B.
Relative angular accuracy:
With reference to the output
period at A and B. The relative accuracy of the edges to
each other at a CPR setting of 256 is within ± 10% for 5V
operation in a typical condition. Therefore, based on a
period at A or B, the edge occurs in a window between 40%
and 60% as shown in the following figure.
Integral non-linearity (INL):
The maximum deviation
between the actual angular position and the position
indicated by the encoder's output count, over one
revolution. It is defined as the most positive linearity error
+INL or the most negative linearity error –INL from the best
fit line, whichever is larger.
Figure 2: Integral Non-Linearity Example
Broadcom
AEAT-8811-Q24-DS100
2
AEAT-8811-Q24
Data Sheet
Magnetic Encoder IC: 10-Bit to 16-Bit Programmable Angular Magnetic Encoder with No
Offset Calibration
Functional Description
Figure 3: AEAT-8811-Q24 Block Diagram
Broadcom
AEAT-8811-Q24-DS100
3
AEAT-8811-Q24
Data Sheet
Magnetic Encoder IC: 10-Bit to 16-Bit Programmable Angular Magnetic Encoder with No
Offset Calibration
Pin Assignment
Figure 4: Pin Configurations for AEAT-8811-Q24
Table 1: Pinout Description
Pin
1–6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Symbol
No Connection
I
B
A
SSI_SCL_SPI_CLK
SSI_SCL_SPI_DI
SSI_SCL_SPI_D0
VSS
VDDA
No Connection
No Connection
No Connection
No Connection
VDDA
VSS
SSI_SCL_SPI_SEL
U
V
W or PWM
VSS
Description
N/A
Index output (ABI mode)
Incremental B output (ABI mode)
Incremental A output (ABI mode)
SSI/SPI clock input
SSI/SPI data input
SSI/SPI data out
Supply ground
5V supply input
No connection
No connection
No connection
No connection
5V supply input
Supply ground
SSI/SPI select pin
U commutation output (UVW mode)
V commutation output (UVW mode)
W commutation (UVW mode)/PWM output
Supply ground
Broadcom
AEAT-8811-Q24-DS100
4
AEAT-8811-Q24
Data Sheet
Magnetic Encoder IC: 10-Bit to 16-Bit Programmable Angular Magnetic Encoder with No
Offset Calibration
The AEAT-8811-Q24 is manufactured with a CMOS standard process. It is capable of accurately measuring a magnet's
rotational angle when it is placed in alignment and perpendicular to the device by using its integrated Hall sensors to detect
its magnetic field. The detected magnetic signals are then taken as input signals to be properly conditioned to negate its non-
idealities before inputting them into the analog amplifiers for strength amplification and filtering. After which, the amplified
analog signals are fed into the internal analog-to-digital converter (ADC) to be converted into digital signals for the final stage
of digital processing.
The digital processing provides a digitized output of the absolute and incremental signals. For optimal performance, the used
magnet's center axis should be aligned with the center of the device with a tolerable displacement radius of 0.5 mm from the
defined Hall sensor center as described in
Magnet and IC Package Placement.
Moreover, the used magnet should have
sufficient magnetic field strength (mT) to generate the magnetic field for the signal generation as highlighted in
Recommended Magnetic Input Specifications.
The device provides digital information of magnetic field strength high (MHi)
and magnetic field strength low (MLo) from the SSI read to indicate whether the magnets are too close or too far away from
the device's surface.
Users can assess the device's digitized absolute data using standard Synchronous Serial Interface (SSI) protocols. In
addition, an absolute angular representation can also be selected using a pulse-width modulated (PWM) signal.
The incremental outputs are available from the digital outputs of their respective A, B, and I pins. This is the same for the U,
V, and W pins.
Absolute Maximum Ratings
Parameter
Storage Temperature
DC Supply Voltage
VDDA Pin
Input Voltage Range
Electrostatic Discharge
Moisture Sensitivity Level
Symbol
T
S
VDD
V
in
—
—
Min.
–40
–0.3
–0.3
–2.0
—
Max.
125
5.5
5.5
+2.0
3
Unit
°C
Volts
Volts
kVolts
—
Notes
—
—
—
—
Maximum floor life = 168 hours
CAUTION!
Subjecting the product to stresses beyond those listed in this section may cause permanent damage to the
devices. These are stress ratings only and do not imply that the devices will function beyond these ratings.
Exposure to the extremes of these conditions for extended periods may affect product reliability.
Electrical Characteristics
Recommended Operating Conditions
Parameter
Operating Ambient Temperature
DC Supply Voltage to VDD Pin
5V Operation
OTP Programming Voltage at
VDDA Pin
Symbol
T
A
VDD
—
Min.
–40
4.5
5.5
Typ.
—
5.0
5.6
Max.
125
5.5
5.7
Unit
°C
Volts
Volts
Notes
—
—
—
Broadcom
AEAT-8811-Q24-DS100
5
