STPMS2 datasheet(21/36 Pages) STMICROELECTRONICS

21 / 36 page

STPMS2

Theory of operation

DocID16525 Rev 5

21/36

LPR (low precision): fCLK = 1 MHz and settings defined by MS0 through MS3

HPR (high precision): the normal mode of operation with fCLK = 2 MHz to 4 MHz

The STPMS2 performs operations in 2 basic modes: hard mode and soft mode. In hard

mode the configuration is set through external pins MS0, MS1, MS2 and MS3. In soft

mode, 40 configuration bits can be accessed through CFG[39:0], via serial communication.

The pins used for serial communication are: MS0, MS1 and MS2. Switching between hard

and soft mode is achieved through pin MS3.



Hard mode: in this case the device configuration is bootstrapped at startup and signals

come from VIN and VIP for voltage channels, and CIP and CIN for current channels or

from internal BIST DAC.



Soft mode: in this mode all possible settings from hard mode are accessible, as well

as the additional settings.

Figure 17: Block diagram of the modulator

The STPMS2 sends selected signals based on the configuration to the DAT and DATn

pins. Both outputs have cross-current and slew rate limiters to prevent excessive current

spikes on supply lines.

STPMS2 Datasheet(PDF) 21 Page - STMicroelectronics