ZAMC4100 Datasheet, PDF (92/155 Pages) Integrated Device Technology – Actuator and Motor Controller

ZAMC4100 Datasheet
Register RCMPCNT
This register contains the number of the consecutive comparator matches before interrupt ADCCMPIF is
generated. If the value of RCMPCNT (Table 3.50) is 00_HEX (default value), the counter is bypassed and the
interrupt flag ADCCMPIF (Table 3.39) is set on the first match. When the conversion is running, this register is
accessed as read-only.
3.12.10. External ADC Analog Inputs Open/Short Diagnostics and Protection
ZAMC4100 provides open/short diagnostics for the analog input pins (AINx) and the sensor supply pin S_P as
well. Pins S_P and AIN1,2 also have short-to-battery protection. The internal protection and diagnostic structure
of the S_P and AINx pins is shown in Figure 3.25.
The diagnostic functionality for all pins (S_P, AINx) is controlled by register AINDIAG described in Table 3.43 and
Table 3.44. Table 3.45 gives the meaning of the corresponding open/short flag from the AINDIAG register with
respect to the combination of AINCSHEN and AINCSLEN bits that enable the diagnostic current sinks/sources
connected to the analog input pins.
The protection against a short to Vbat on the S_P and AIN1,2 pins relies on Zener-like structure inside the
ZAMC4100 that limits the voltage propagated to the internal circuitries to a safe level. The limitation of the current
through the S_P pin in the event of such a failure is achieved with an internal resistor connected in series (see
Figure 3.25-A. For the AIN1,2 pins this resistor is external (R2 and R3 on the application diagram as shown in
Figure 6.1).
The protection against a short to GND on the S_P pin is achieved by limitation of the load current. Its value is
specified in Table 1.4 as parameter I_{SP_OC}.
Note: Enabled diagnostic current sources during ADC conversion might result in inaccurate results. Disable all
AINx and S_P pin diagnostics before starting an ADC conversion.
Figure 3.25 ADC Analog Inputs Protection and Open/Short Detection Circuitry
A) S_P pin protection and diagnostic
ZAMC4100
VDD5V0
VDD5V0
SPSWEN
AINCSHEN
B) AINx pin diagnostic
ZAMC4100
VDD5V0
AINCSHEN
S_P
Open/Short
Detect
SPOSF
AINCSLEN
AINx
Open/Short
Detect
AINxOSF
AINCSLEN
© 2016 Integrated Device Technology, Inc.
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January 26, 2016