Maxim Integrated MAXQ7667 - Manual (Page 269)

16-3 __________________________________________________________________________________________________________
MAXQ7667 User’s Guide
SECTION 16: POWER-SUPPLY/SUPERVISORY MONITORING
The MAXQ7667 power-supply/supervisory monitoring module supports dedicated supply pins to independently power analog, digital
I/O, and digital core functions. The analog functions, digital core, and the digital I/O can be powered from an internal regulator.
The MAXQ7667 power-supply/supervisory monitoring module includes the following features:
• Dedicated analog supply (+3.3V) pins
• Dedicated digital I/O supply (+5.0V) pins
• Dedicated digital core supply (+2.5V) pins
• On-chip +2.5V regulator with a dedicated output pin
• On-chip +3.3V regulator with a dedicated output pin
• On-chip +5.0V regulator (needs an external pass transistor for operation)
• Digital core voltage monitor
• Digital I/O voltage monitor
• Analog voltage monitor
• Preset threshold voltage level for power-on reset
• Preset threshold voltage level for digital core interrupt generation
• Preset threshold voltage level for digital I/O interrupt generation
• Preset threshold voltage level for analog interrupt generation
• Four reset sources: power-on (brownout), external, watchdog timer, and internal system
16.1 Power-Supply/Supervisory Module Pins
Table 16-1 shows the MAXQ7667 power-supply module signals.
Table 16-1. MAXQ7667 Power-Supply Module Pins
POWER-SUPPLY
SIGNAL
PIN FUNCTION
AVDD 27, 32
Analog Supply (+3.3V). AVDD is the power-supply pin for all analog functions. Connect to REG3P3 and
bypass with a 0.1µF capacitor to ground for self-powered operation.
AGND 28, 31, 33 Analog Ground
DVDD 6, 19, 42
Digital Supply Voltage (+2.5V). Connect all DVDD pins to the same point. Connect to REG2P5 and
bypass with a 0.1µF capacitor to ground for self-powered operation.
DVDDIO 8,17, 44
I/O Supply Voltage (+5.0V). DVDDIO is the power-supply pin for all digital input/output pins. Connect all
DVDDIO pins to the same point.
DGND 7, 18, 43 Digital Ground
RESET 25
Active-Low Reset Input/Output. Open-drain signal with internal pullup resistor to DVDD that remains low
until DVDD rises above the brownout-reset (BOR) threshold and a timeout period expires. RESET is
pulled low by internal circuitry if DVDD falls below its brownout reset value. It can also be pulled low by
the internal watchdog timer, or externally by the user.
GATE5 24
DVDDIO Pass Transistor Voltage Regulation Control. GATE5 connects directly to the gate of a depletion
mode transistor or through level-shifting diodes to an enhancement mode or npn Darlington transistor that
supplies 5V to DVDDIO.
REG2P5 22
+2.5V Regulator Output. For self-powered operation, connect to DVDD and bypass to DGND with a 0.1µF
capacitor.
REG3P3 23
+3.3V Regulator Output. For self-powered operation, connect to AVDD and bypass to AGND with a 0.1µF
capacitor.