SH3100 Datasheet, PDF (3/80 Pages) Semtech Corporation – Supervisory IC with I2C Interface and PWM

SH3100
POWER MANAGEMENT
Table of Contents (continued)
Functional Descriptions ............................................................................................. .................................................................. 55
32.768 kHz Crystal Oscillator ................................................................................... .................................................................. 55
Plot of Crystal Padding Capacitance versus Adjustment Code .............................. .................................................................. 56
Internal 32.768 kHz Oscillator .................................................................................. .................................................................. 56
System Reset – Programmable VDD Threshold (VBO) ............................................ .................................................................. 57
Programmable Reset Duration ................................................................................. .................................................................. 58
System Reset - Watchdog Timer (WDT) .................................................................... .................................................................. 59
System Reset - Manual Override ............................................................................... .................................................................. 59
Real Time Clock (RTC) ............................................................................................... .................................................................. 60
Periodic Interval Timer (PIT) ...................................................................................... .................................................................. 61
Interrupt Operation .................................................................................................... .................................................................. 62
I²C Short-Form Interrupt Clear .................................................................................. .................................................................. 63
General Purpose 8-Bit DAC & Comparator ............................................................... .................................................................. 64
Temperature Measurement ...................................................................................... .................................................................. 65
PWM Operation & Fan Speed Control ...................................................................... .................................................................. 66
Auto-PWM Mode (Fan Control Mode) ....................................................................... .................................................................. 66
Auto-PWM Engine Features: ...................................................................................... ........................................................... 66, 67
Erratum ....................................................................................................................... .................................................................. 67
Manual PWM Control ................................................................................................. .................................................................. 67
PWM Mode ................................................................................................................. .................................................................. 68
Switching Regulator Operation ................................................................................. .................................................................. 69
Low Dropout Linear Regulator (LDO) ........................................................................ .................................................................. 70
I²C Interface ............................................................................................................... .................................................................. 71
Combined Write Format ............................................................................................ .................................................................. 71
Normal Write Format ................................................................................................. .................................................................. 71
Combined Read Format ............................................................................................ .................................................................. 72
I²C Timing Diagrams .................................................................................................. .................................................................. 73
High-Frequency Digitally-Controlled Oscillator (HFDCO) .......................................... ................................................................. 74
Spectrum Spreading .................................................................................................. .................................................................. 75
Clock Management & Frequency Locked Loop (FLL) .............................................. .................................................................. 76
CLK0 & CLK1 Outputs ............................................................................................... .................................................................. 77
HFDCO Clock On/Off Control ..................................................................................... .................................................................. 78
Outline Drawing and Land Pattern ............................................................................ .................................................................. 79
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