54.11 PTC Characteristics

Table 54-35. Sensor Load Capacitance
Symbol	Mode	PTC channel	Max Sensor Load ⁽¹⁾	Units
Cload	Self-capacitance	Y0	54	pF
		Y1
		Y2
		Y3
		Y4
		Y5
		Y6
		Y7
		Y8
		Y9
		Y10
		Y11
		Y12
		Y13
		Y14
		Y15
		Y16	51
		Y17	54
		Y18
		Y19
		Y20
		Y21	51
		Y22	54
		Y23
		Y24
		Y25
		Y26
		Y27
		Y28
		Y29
		Y30
		Y31
	Mutual-capacitance	All	31

Note:

Capacitance load that the PTC circuitry can compensate for each channel.

Table 54-36. Analog Gain Settings ^{(1)
(2)}
Symbol	Setting	Average
Gain	GAIN_1	1
	GAIN_2	2.0
	GAIN_4	4.2
	GAIN_8	9.1
	GAIN_16	15.4
	GAIN_32	-

Note:

Analog Gain is a parameter of the QTouch Library. Refer to the “QTouch Library Peripheral Touch Controller User Guide” for additional information.
The GAIN_16 and GAIN_32 settings are not recommended; otherwise, the PTC measurements might become unstable.

The values in the following Power Consumption table are measured values of power consumption under the following conditions:

Operating Conditions:

VDD = 3.0V

Clocks:

DFLL48M used as main clock source, running undivided at 48 MHz

CPU is running on flash with 2 wait states, at 48 MHz

PTC running at 4 MHz

PTC Configuration

Mutual-Capacitance mode

One touch channel

System Configuration

Standby Sleep mode enabled

RTC running on ULP32K: used to define the PTC scan rate, through the event system

RTC interrupts (wake up) the CPU to perform PTC scans

Table 54-37. Power Consumption ⁽¹⁾
Symbol	Parameters	PTC scan rate (msec)	Oversamples	TA	Typ.	Max	Units
IDD	Current Consumption	10	4	Max 85°C Typ 25°C	137	1164	µA
		10	16		146	1179
		50	4		77	1094
		50	16		79	1100
		100	4		68	1086
		100	16		69	1089
		200	4		64	1085
		200	16		65	1087

Note:

These values are based on characterization.

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