NXP Semiconductors K22F series, Reference Manual, Page: 589 / 1407

Chapter 27
RTC Oscillator (OSC32K)
27.1 Introduction
NOTE
For the chip-specific implementation details of this module's
instances, see the chip configuration information.
The RTC oscillator module provides the clock source for the RTC. The RTC oscillator
module, in conjunction with an external crystal, generates a reference clock for the RTC.
27.1.1 Features and Modes
The key features of the RTC oscillator are as follows:
• Supports 32 kHz crystals with very low power
• Consists of internal feed back resistor
• Consists of internal programmable capacitors as the C
load
of the oscillator
• Automatic Gain Control (AGC) to optimize power consumption
The RTC oscillator operations are described in detail in Functional Description .
27.1.2 Block Diagram
The following is the block diagram of the RTC oscillator.
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 589