SH3100

POWER MANAGEMENT

3

© 2006 Semtech Corp.

www.semtech.com

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

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

Combined Write Format ............................................................................................ .................................................................. 71

Normal Write Format ................................................................................................. .................................................................. 71

Combined Read Format ............................................................................................ .................................................................. 72

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