AS5030-ATST austriamicrosystems, AS5030-ATST Datasheet - Page 30

• Manufacturer Part Number: AS5030-ATST
• Description: IC ENCODER ROTARY 8-BIT 16-TSSOP
• Manufacturer: austriamicrosystems
• Type: Linear, Rotary Encoder - Programmabler

Specifications of AS5030-ATST

• Sensing Range: 23.6mT ~ 44.5mT
• Voltage - Supply: 4.5 V ~ 5.5 V
• Current - Supply: 14mA
• Current - Output (max): 4mA
• Output Type: Digital, PWM
• Features: Programmable
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: AS5030-ATSTTR

AS5030
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Chip Internal Lowpass Filtering.
anti-aliasing filter. The filter characteristic must be chosen carefully to balance propagation delay and noise.
The lowpass filter in the AS5030 has a cut-off frequency of typ. 23.8kHz and the overall propagation delay in the analog signal path is typ.
15.6µs.
Digital Readout Rate.
considered. Due to its nature, a PWM signal is not very usable at high speeds, as you get only one reading per PWM period. Increasing the
PWM frequency may improve the situation but causes problems for the receiving controller to resolve the PWM steps. The frequency on the
AS5030 PWM output is typ. 1.95kHz with a resolution of 2µs/step.
A more suitable approach for high speed absolute angle measurement is using the serial interface. With a clock rate of up to 6MHz, a complete
set of data (21bits) can be read in >3.5µs
8.6.2 Total Propagation Delay of the AS5030
The total propagation delay of the AS5030 is the delay in the analog signal path and the tracking rate of the ADC:
15.6µs + 1.15µs = 16.75µs.
If only the SIN-/COS-outputs are used, the propagation delay is the analog signal path delay only (typ. 15.6µs).
Position Error over Speed.
The angle error over speed caused by the propagation delay is calculated as:
In addition, the anti-aliasing filter causes an angle error calculated as:
Examples of the overall position error caused by speed, including both propagation delay and filter delay:
8.7 Reduced Power Modes
The AS5030 can be operated in 3 reduced power modes. All 3 modes have in common that they switch off or freeze parts of the chip during
intervals between measurements. In Low Power Mode or Ultra Low Power Mode, the AS5030 is not operational, but due to the fast start-up, an
angle measurement can be accomplished very quickly and the chip can be switched to reduced power immediately after a valid measurement
has been taken. Depending on the intervals between measurements, very low average power consumption can be achieved using such a
strobed measurement mode.
www.austriamicrosystems.com/AS5030
Low Power Mode:reduced current consumption, very fast start-up. Ideal for short sampling intervals (<3ms)
Ultra Low Power Mode:further reduced current consumption, but slower start-up than Low Power Mode. Ideal for sampling intervals from
3….200ms
Power Cycle mode:zero power consumption (externally switched off) during sampling intervals, but slower start-up than Ultra Low Power
Mode. Ideal for sampling intervals 200ms
Speed (rpm)
10000
1000
100
Aside from the chip-internal propagation delay, the time required to read and process the angle data must also be
Total Position Error
(Δφ
0.0175°
pd
0.175°
1.75°
A commonplace practice for systems using analog-to-digital converters is to filter the input signal by an
+ Δφl
pf
)
Δφ
pd
Δφ
= rpm * 6 * 16.75E
lpf
= ArcTan [ rpm / ( 60*f
Revision 2.1
-6
in degrees
0
) ]
30 - 44
(EQ 4)
(EQ 5)