3 VOLT OPERATION / 5 VOLT TOLERANCE
The LPC47M10x is a 3.3 Volt part. It is intended solely for 3.3V applications. Non-LPC bus pins are 5V tolerant; that
is, the input voltage is 5.5V max, and the I/O buffer output pads are backdrive protected.
The LPC interface pins are 3.3 Volt only. These signals meet PCI DC specifications for 3.3V signaling. These pins
are:
•
•
•
•
LAD[3:0]
nLFRAME
nLDRQ
nLPCPD
The input voltage for all other pins is 5.5V max. These pins include all non-LPC Bus pins and the following pins:
•
•
•
•
nPCI_RESET
PCI_CLK
SER_IRQ
nIO_PME
POWER FUNCTIONALITY
The LPC47M10x has three power planes: VCC, VTR and VREF.
VCC Power
The LPC47M10x is a 3.3 Volt part. The VCC supply is 3.3 Volts (nominal). See the Operational Description Section
and the Maximum Current Values sub-section.
VTR Support
The LPC47M10x requires a trickle supply (VTR) to provide sleep current for the programmable wake-up events in the
PME interface when VCC is removed. The VTR supply is 3.3 Volts (nominal). See the Operational Description
Section. The maximum VTR current that is required depends on the functions that are used in the part. See Trickle
Power Functionality and Maximum Current Values sub-sections. If the LPC47M10x is not intended to provide wake-
up capabilities on standby current, VTR can be connected to VCC. VTR powers the IR interface, the PME configuration
registers and the PME interface. The VTR pin generates a VTR Power-on-Reset signal to initialize these components.
Note: If VTR is to be used for programmable wake-up events when VCC is removed, VTR must be at its full minimum
potential at least 10 μs before Vcc begins a power-on cycle. When VTR and Vcc are fully powered, the potential
difference between the two supplies must not exceed 500mV.
Internal PWRGOOD
An internal PWRGOOD logical control is included to minimize the effects of pin-state uncertainty in the host interface
as Vcc cycles on and off. When the internal PWRGOOD signal is “1” (active), Vcc > 2.3V (nominal), and the
LPC47M10x host interface is active. When the internal PWRGOOD signal is “0” (inactive), Vcc ≤ 2.3V (nominal), and
the LPC47M10x host interface is inactive; that is, LPC bus reads and writes will not be decoded.
The LPC47M10x device pins nIO_PME, CLOCKI32, KDAT, MDAT, IRRX, nRI1, nRI2, RXD2 and most GPIOs (as
input) are part of the PME interface and remain active when the internal PWRGOOD signal has gone inactive,
provided VTR is powered. The IRTX2/GP35, GP53/TXD2(IRTX), GP60/LED1 and GP61/LED2 pins also remain
active when the internal PWRGOOD signal has gone inactive, provided VTR is powered. See Trickle Power
Functionality section. The internal PWRGOOD signal is also used to disable the IR Half Duplex Timeout.
32.768 kHz Trickle Clock Input
The LPC47M10x utilizes a 32.768 kHz trickle input to supply a clock signal for the fan tachometer logic, LED blink
and wake on specific key function. See the following section for more information.
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