AS5134-ASSU austriamicrosystems, AS5134-ASSU Datasheet - Page 25

• Manufacturer Part Number: AS5134-ASSU
• Description: ENCODER, MAGNETIC, ROTARY, 8BIT, 20SSOP
• Manufacturer: austriamicrosystems

Specifications of AS5134-ASSU

• Brief Features: 9-Bit Multiturn Counter, User Programmable Zero Position And Sensitivity
• Supply Voltage Range: 4.5V To 5.5V
• Operating Temperature Range: -40°C To +140°C
• Digital Ic Case: RoHS Compliant
• Ic Function: Programmable High Speed Magnetic Rotary Encoder
• Rohs Compliant: Yes

AS5134
Data Sheet - D e t a i l e d D e s c r i p t i o n
Low Power Mode
The target of this mode is to reduce the long time power consumption of the device for battery powered applications,
without losing the actual angle information.
In Low Power Mode, the AS5134 is inactive. The last state (for e.g. the angle, AGC value, etc.) is frozen and the chip
starts from this frozen state when it resumes active operation. This method provides much faster start-up than a “cold
start” from zero. If the AS5134 is cycled between active and reduced current mode, a substantial reduction of the
average supply current can be achieved. The minimum dwelling time is <0.5 ms. The actual active time depends on
how much the magnet has moved while the AS5134 was in reduced power mode. The angle data is valid, when the
status bit LOCK has been set. Once a valid angle has been measured, the AS5134 can be put back to reduced power
mode. The average power consumption can be calculated as:
Where:
I
I
I
t
t
To access the Low Power Mode, the bit ‘LP’ <15> of the digital interface has to be set to “1”.
Figure 17. Low Power Mode Connection
Reducing Power Supply Peak Currents
An optional RC-filter (R1/C1) may be added to avoid peak currents in the power supply line when the AS5134 is
toggled between active and reduced power mode. R1 must be chosen such that it can maintain a VDD voltage of 4.5 –
5.5V under all conditions, especially during long active periods when the charge on C1 has expired. C1 should be
chosen such that it can support peak currents during the active operation period. For long active periods, C1 should be
large and R1 should be small.
www.austriamicrosystems.com
avg
active
power_down
on
off
= Time period during which the chip is operated in active mode
= Time period during which the chip is in reduced power mode
= Average current consumption
= Current consumption in active mode
= I
off
: Current consumption in reduced power mode (max. 120µA)
I
avg
C1
=
I
-------------------------------------------------------------------- -
active
100n
∗ t
on
t
on
+
AS5134
I
+
powerdown
t
off
S
VDD
VSS
∗ t
N
off
C2
Revision 1.8
I
I
on
off
CS
DCLK
DIO
R1
sampling interval = t
t
on
t
off
on/off
Controller
VDD
VSS
Micro
on
+ t
off
VDD
+5V
VSS
25 - 39
(EQ 5)