Device Architecture
Pin Descriptions
Supply Pins
GND
Ground
Ground supply voltage to the core, I/O outputs, and I/O logic.
GNDQ
Ground (quiet)
Quiet ground supply voltage to input buffers of I/O banks. Within the package, the GNDQ plane is
decoupled from the simultaneous switching noise originated from the output buffer ground domain. This
minimizes the noise transfer within the package and improves input signal integrity. GNDQ needs to
always be connected on the board to GND. Note: In FG256, FG484, and FG676 packages, GNDQ and
GND pins are connected within the package and are labeled as GND pins in the respective package pin
assignment tables.
ADCGNDREF
Analog Reference Ground
Analog ground reference used by the ADC. This pad should be connected to a quiet analog ground.
GNDA
Ground (analog)
Quiet ground supply voltage to the Analog Block of Fusion devices. The use of a separate analog ground
helps isolate the analog functionality of the Fusion device from any digital switching noise. A 0.2 V
maximum differential voltage between GND and GNDA/GNDQ should apply to system implementation.
GNDAQ
Ground (analog quiet)
Quiet ground supply voltage to the analog I/O of Fusion devices. The use of a separate analog ground
helps isolate the analog functionality of the Fusion device from any digital switching noise. A 0.2 V
maximum differential voltage between GND and GNDA/GNDQ should apply to system implementation.
Note: In FG256, FG484, and FG676 packages, GNDAQ and GNDA pins are connected within the
package and are labeled as GNDA pins in the respective package pin assignment tables.
GNDNVM
Flash Memory Ground
Ground supply used by the Fusion device's flash memory block module(s).
GNDOSC
Oscillator Ground
Ground supply for both integrated RC oscillator and crystal oscillator circuit.
VCC15A
Analog Power Supply (1.5 V)
1.5 V clean analog power supply input for use by the 1.5 V portion of the analog circuitry.
VCC33A
Analog Power Supply (3.3 V)
3.3 V clean analog power supply input for use by the 3.3 V portion of the analog circuitry.
VCC33N
Negative 3.3 V Output
This is the –3.3 V output from the voltage converter. A 2.2 µF capacitor must be connected from this pin
to ground.
VCC33PMP
Analog Power Supply (3.3 V)
3.3 V clean analog power supply input for use by the analog charge pump. To avoid high current draw,
VCC33PMP should be powered up simultaneously with or after VCC33A.
VCCNVM
Flash Memory Block Power Supply (1.5 V)
1.5 V power supply input used by the Fusion device's flash memory block module(s). To avoid high
current draw, VCC should be powered up before or simultaneously with VCCNVM.
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