Device Architecture
Temperature Monitor
The final pin in the Analog Quad is the Analog Temperature (AT) pin. The AT pin is used to
implement an accurate temperature monitor in conjunction with an external diode-connected
bipolar transistor (Figure 2-76). For improved temperature measurement accuracy, it is important
to use the ATRTN pin for the return path of the current sourced by the AT pin. Each ATRTN pin is
shared between two adjacent Analog Quads. Additionally, if not used for temperature monitoring,
the AT pin can provide functionality similar to that of the AV pad. However, in this mode only
positive voltages can be applied to the AT pin, and only two prescaler factors are available (16 V
and 4 V ranges—refer to Table 2-54 on page 2-128).
Discrete
Bipolar
Transistor
Off-Chip
ATRTN
AV
AC
AG
AT
Voltage
Monitor Block
Current
Monitor Block
Gate
Driver
Temperature
Monitor Block
Pads
On-Chip
Analog Quad
Prescaler
Prescaler
Prescaler
Power
MOSFET
Gate Driver
Digital
Input
Digital
Input
Digital
Input
Current
Monitor / Instr
Amplifier
Temperature
Monitor
To FPGA
(DAVOUTx)
To FPGA
(DACOUTx)
From FPGA
(GDONx)
To FPGA
(DATOUTx)
To Analog MUX
To Analog MUX
To Analog MUX
Figure 2-76 • Temperature Monitor Quad
Fusion uses a remote diode as a temperature sensor. The Fusion Temperature Monitor uses a
differential input; the AT pin and ATRTN (AT Return) pin are the differential inputs to the
2-96
Preliminary v1.7
ACTEL [ Actel Corporation ]
