AS5261

Datasheet - Detailed Descr i p ti on

www.ams.com

Revision 1.1

14 - 32

For efficient use of diagnostics, it is recommended to program to clamping levels CLL and CLH.

8.2.7 Noise Suppressor

The noise suppressor is inserted on two levels of the DSP chain. The first stage, on the output of the Cordic block, is capable to reduce the noise

level up to 1 LSB peak to peak. The second stage, on the output of the straight-line tracer, reduces the impact of the post processing. In fact

depending on the programmed operating angular sector the gain module amplifies also the noise level up to 8 LSB peak to peak and the second

stage of the noise suppressor reduces it again to 1 LSB peak to peak.

Four possible configurations of the noise suppressor can be selected via the OTP bits FILTERCFG<1:0>.

8.2.8 Hysteresis Function

AS5261 device includes a hysteresis function to avoid sudden jumps from CLH to CLL and vice versa caused by noise in the full turn

configuration.

The hysteresis amplitude can be selected via the OTP bits HYSTSEL<1:0>.

8.3 PWM Output Driver Parameters

The output stage is configured in a open drain output.

The PWM duty cycle represents the angular output data. All programming features are available for the PWM mode as well. The PWM period is

programmable in four steps and can be programmed by PWMF<2:0>.

Ω

Table 8. Different Failure Cases of AS5261

Type

Failure Mode

Symbol

Failure Band

Note

Internal alarms (failures)

Out of magnetic range

(too less or too high magnetic input)

MAGRng

High/Low

Programmable by OTP bit DIAG_HIGH

Cordic overflow

COF

High/Low

Programmable by OTP bit DIAG_HIGH

Offset compensation finished

OCF

High/Low

Programmable by OTP bit DIAG_HIGH

Watchdog fail

WDF

High/Low

Programmable by OTP bit DIAG_HIGH

Oscillator fail

OF

High/Low

Programmable by OTP bit DIAG_HIGH

Application related

failures

Overvoltage condition

OV

High

Dependant on the load resistor

Pull up

→ failure band high

Broken VDD

BVDD

Broken VSS

BVSS

Short circuit output

SCO

High

Switch off

→ short circuit dependent

Table 9. PWM Parameters Output Driver

Symbol

Parameter

Conditions

Min

Typ

Max

Units

PWMF1

PWM frequency 7

PWMF<2:0>=111

109.86

122

134.28

Hz

PWMF2

PWM frequency 6

PWMF<2:0>=110

179.78

200

219.73

Hz

PWMF3

PWM frequency 5

PWMF<2:0>=101

219.73

244

268.55

Hz

PWMF4

PWM frequency 4

PWMF<2:0>=100

329.59

366

402.83

Hz

PWMF5

PWM frequency 3

PWMF<2:0>=011

494.38

549

604.25

Hz

PWMF6

PWM frequency 2

PWMF<2:0>=010

659.18

732

805.66

Hz

PWMF7

PWM frequency 1

PWMF<2:0>=001

988.77

1100

1208.50

Hz

PWMF8

PWM frequency 0

PWMF<2:0>=000

1977.54

2197

2416.2

Hz

PWMDC

PWM duty cycle range

info parameter

4

96

%

PWMVOL

Output voltage low

IOUT=5mA

0

0.4

V

PWMSRF

PWM slew rate (falling edge)

Between 75% and 25%

RPUOUT=4K

Ω; CLOUT=1nF

VDD=5V

12

4

V / µs