Actel Fusion Mixed-Signal FPGAs
Pr el iminar y v1 .7
1-5
quad consists of three analog inputs and one gate driver. Each quad can be configured in various
built-in circuit combinations, such as three prescaler circuits, three digital input circuits, a current
monitor circuit, or a temperature monitor circuit. Each prescaler has multiple scaling factors
programmed by FPGA signals to support a large range of analog inputs with positive or negative
polarity. When the current monitor circuit is selected, two adjacent analog inputs measure the
voltage drop across a small external sense resistor. Built-in operational amplifiers amplify small
voltage signals (2 mV sensitivity) for accurate current measurement. One analog input in each quad
can be connected to an external temperature monitor diode and achieves detection accuracy of
±3C. In addition to the external temperature monitor diode(s), a Fusion device can monitor an
internal temperature diode using dedicated channel 31 of the ADCMUX.
shown is configured to monitor and control an external power supply. The AV pad measures the
source of the power supply. The AC pad measures the voltage drop across an external sense resistor
to calculate current. The AG MOSFET gate driver pad turns the external MOSFET on and off. The AT
pad measures the load-side voltage level.
Embedded Memories
Flash Memory Blocks
The flash memory available in each Fusion device is composed of one to four flash blocks, each 2
Mbits in density. Each block operates independently with a dedicated flash controller and
interface. Fusion flash memory blocks combine fast access times (60 ns random access and 10 ns
access in Read-Ahead mode) with a configurable 8-, 16-, or 32-bit datapath, enabling high-speed
Figure 1-1 Analog Quad
Analog Quad
AV
AC
AT
Voltage
Monitor Block
Current
Monitor Block
AG
Power
Line Side
Load Side
Pre-
scaler
Digital
Input
Power
MOSFET
Gate Driver
Current
Monitor/Instr
Amplifier
Temperature
Monitor
Digital
Input
Digital
Input
Pre-
scaler
Pre-
scaler
Pads
To Analog MUX
To FPGA
(DAVOUTx)
To FPGA
(DACOUTx)
To FPGA
(DATOUTx)
On-Chip
Gate
Driver
Temperature
Monitor Block
Off-Chip
Rpullup
From FPGA
(GDONx)