TLE9869QXA20_15 Datasheet, PDF (28/122 Pages) Infineon Technologies AG – Microcontroller with LIN and H-Bridge MOSFET Driver for Automotive Applications

TLE9869QXA20
System Control Unit - Digital Modules (SCU-DM)
CGU
OSHCP_OCSOCNCON
PLLCON
CMCON
SYSCON0
XTAL1
XTAL2
OSC_HP
LPL_PC_LCKLK
PMU
PLL
f_OSC
f_{LP_CLK}
Figure 9 Clock Generation Unit Block Diagram
The following sections describe the different parts of the CGU.
CCU
f_SYS
CGU_ block
6.3.1 Low Precision Clock
The clock source LP_CLK is a low-precision RC oscillator (LP-OSC) with a nominal frequency of 18 MHz that is
enabled by hardware as an independent clock source for the TLE9869QXA20 startup after reset and during the
power-down wake-up sequence. f_{LP_CLK} is not user configurable.
6.3.2 High Precision Oscillator Circuit (OSC_HP)
The high precision oscillator circuit, designed to work with both an external crystal oscillator or an external stable
clock source, consists of an inverting amplifier with XTAL1 as the input, and XTAL2 as the output.
Figure 10 shows the recommended external circuitry for both operating modes, External Crystal Mode and
External Input Clock Mode.
6.3.2.1 External Input Clock Mode
When supplying the clock signal directly, not using an external crystal and bypassing the oscillator, the input
frequency needs to be equal to or greater than 4 MHz if the PLL VCO part is used.
When using an external clock signal, it must be connected to XTAL1. XTAL2 is left open (unconnected).
6.3.2.2 External Crystal Mode
When using an external crystal, its frequency can be within the range of 4 MHz to 25 MHz. An external oscillator
load circuitry must be used, connected to both pins, XTAL1 and XTAL2. It normally consists of the two load
capacitances C1 and C2. A series damping resistor could be required for some crystals. The exact values and the
corresponding operating ranges depend on the crystal and have to be determined and optimized in cooperation
with the crystal vendor using the negative resistance method. The following load cap values can be used as
starting point for the evaluation:
Data Sheet
28
Rev. 1.0, 2015-04-30