SCPS286 July 2025 TPLD2001
ADVANCE INFORMATION
In order for the ACMP macro-cell to be used in a TPLD design, the power up (PWR UP) port needs to be connected to a logic High signal. By connecting to signals coming from the connection mux, it is possible to have the ACMP always on, always off, or switched on dynamically based on a digital signal coming from the connection mux.
The ACMP macro-cell has a positive input signal that can be provided by a variety of external sources with a selectable gain stage before going into the analog comparator. The negative input signal can either come from the internal VREF or an external source, which is shared between all comparator channels.
| Parameters | Source |
|---|---|
| IN+ source | ACMP IN0 |
ACMP IN1 | |
| ACMP IN2 | |
| ACMP IN3 |
IN+ gain: The McACMP positive input can be provided by a variety of external sources, and can also have a selectable gain stage (1X, 0.5X, 0.33X, 0.25X) before connecting to the analog comparator.
IN- voltage range: 32 mV to 2.016 V through the internal VREF or up to 2.016 V external source.
The VREF selection per discrete analog comparator may be updated in-system using the User Registers. For glitch-free measurements, it is recommended to disable/power down all analog comparators when changing the VREF. If the analog comparator is not disabled while the VREF selection is being updated, it may take up to 10µs for valid data to be output from the analog comparators.
Hysteresis: If the internal VREF is used, corresponding ACMP channels have four selectable hysteresis options 0 mV, 32 mV, 64 mV and 192 mV.
Low bandwidth: The ACMP cell has a selection for the bandwidth of the input signal, which can be used to save power and reduce noise impact when lower bandwidth signals are being compared.