Datasheet

18 Maxim Integrated
16-Bit Microcontrollers with
Infrared Module and Optional USB
MAXQ612/MAXQ622
Pin Descriptions—Bare Die
PIN
NAME FUNCTION
MAXQ612 MAXQ622
POWER PINS
28 28 V
DD
Supply Voltage
8, 30, 45, 73
8, 23, 30, 45,
73
GND Ground
29 29 REG18
Regulator Capacitor. This pin must be connected to ground through a 1.0FF
external ceramic-chip capacitor. The capacitor must be placed as close to this
pin as possible. No external devices other than the capacitor should be con-
nected to this pin.
RESET PINS
21 21
RESET
Digital, Active-Low, Reset Input/Output. The CPU is held in reset when this pin is
low and begins executing from the reset vector when released. The pin includes
pullup current source and should be driven by an open-drain, external source
capable of sinking in excess of 4mA. This pin is driven low as an output when an
internal reset condition occurs.
CLOCK PINS
31 31 HFXIN
High-Frequency Crystal Input. Connect an external crystal or resonator between
HFXIN and HFXOUT as the high-frequency system clock. Alternatively, HFXIN is
the input for an external, high-frequency clock source when HFXOUT is shorted
to ground during POR.
32 32 HFXOUT
USB FUNCTION PINS
— 25 V
BUS
USB V
BUS
Supply Voltage. Connect V
BUS
to a positive 5.0V power supply.
Bypass V
BUS
to ground with a 1.0FF ceramic capacitor as close to the V
BUS
pin
as possible.
— 22 DP
USB D+ Signal. This bidirectional pin carries the positive differential data or
single-ended data. Connect this pin to a USB “B” connector. This pin is weakly
pulled high internally when the USB is disabled.
— 24 DM
USB D- Signal. This bidirectional pin carries the negative differential data or
single-ended data. Connect this pin to a USB “B” connector. This pin is weakly
pulled high internally when the USB is disabled.
— 26 V
DDB
USB Transceiver Supply Voltage. This is the power output of the internal voltage
regulator that is used for the USB transceiver (3.3V) block. This pin is bypassed
to ground with a 1.0FF capacitor as close as possible to the package. No exter-
nal circuitry should be powered from this pin.
— 27 V
DDIO
Switched 3V Power Supply. This is the power output after selection between
V
BUS
and V
DD
. Must be connected to an external ceramic chip capacitor. The
capacitor must be placed as close to this pin as possible. No external devices
other than the capacitor should be connected to this pin.