AS5045

Data Sheet

www.austriamicrosystems.com

Revision 1.7

20 – 33

Figure 12. OTP Programming Connection of AS5045 (shown with AS5045 demoboard)

11.4 Analog Readback Mode

Non-volatile programming (OTP) uses on-chip zener diodes, which become permanently low resistive when

subjected to a specified reverse current.

The quality of the programming process depends on the amount of current that is applied during the programming

process (up to 130mA). This current must be provided by an external voltage source. If this voltage source cannot

provide adequate power, the zener diodes may not be programmed properly.

In order to verify the quality of the programmed bit, an analog level can be read for each zener diode, giving an

indication whether this particular bit was properly programmed or not.

To put the AS5045 in Analog Readback Mode, a digital sequence must be applied to pins CSn, PROG and CLK as

shown in Figure 13. The digital level for this pin depends on the supply configuration (3.3V or 5V; see section 13

3V / 5V Operation).

The second rising edge on CSn (OutpEN) changes pin PROG to a digital output and the log. high signal at pin PROG

must be removed to avoid collision of outputs (grey area in Figure 13).

must be saved as a reference for the calculation of the subsequent programmed and unprogrammed OTP bits.

Following this step, each rising slope of CLK outputs one bit of data in the reverse order as during programming

(see Figure 10: Md0-MD1-Div0,Div1-Indx-Z0…Z11, ccw).

If a capacitor is connected to pin PROG, it should be removed during analog readback mode to allow a fast readout

rate. If the capacitor is not removed the analog voltage will take longer to stabilize due to the additional capacitance.

value gives an indication on the quality of the programmed bit: a reading of <100mV indicates a properly

programmed bit and a reading of >1V indicates a properly unprogrammed bit.

A reading between 100mV and 1V indicates a faulty bit, which may result in an undefined digital value, when the

OTP is read at power-up.

Following the 18