ST92F124/F150/F250 - GENERAL DESCRIPTION
1.3 VOLTAGE REGULATOR
The internal Voltage Regulator (VR) is used to
power the microcontroller starting from the exter-
nal power supply. The VR comprises a Main volt-
age regulator and a Low-power regulator.
non-stabilized and non-thermally-compensated
voltage sufficient for maintaining the data in
RAM and the Register File.
For both the Main VR and the Low-Power VR, sta-
bilization is achieved by an external capacitor,
– The Main voltage regulator generates sufficient
current for the microcontroller to operate in any
mode. It has a static power consumption (300
µA typ.).
connected to one of the V
pins. The minimum
REG
recommended value is 300 nF, and care must be
taken to minimize distance between the chip and
the capacitor. Care should also be taken to limit
the serial inductance to less than 60nH.
– The separate Low-Power regulator consumes
less power is used only when the microcontrol-
ler is in Low Power mode. It has a different de-
sign from the main VR and generates a lower,
Figure 16. Recommended Connections for V
REG
PQFP100
TQFP100
QFP64
Pin 28
Pin 43
Pin 31
Pin 28
Pin 40
C
C
C
L
L
L
C = 300 to 600nF
L = Ferrite bead for EMI protection.
Suggested type: Murata BLM18BE601FH1: (Imp. 600 Ω at 100 MHz).
IMPORTANT: The V pin cannot be used to drive external devices.
REG
Figure 17. Minimum Required Connections for V
REG
PQFP100
TQFP100
QFP64
Pin 31
Pin 43
Pin 28
Pin 40
Pin 28
C
C
C
C = 300 to 600nF
Note: Pin 31 of PQFP100 or pin 28 of TQFP100 can be left unconnnected. A secondary stabilization net-
work can also be connected to these pins.
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STMICROELECTRONICS [ ST ]
