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RH850/U2A 292pin
3.3
Device Core Voltage (VDD) Selection
The device core voltage VDD (typ.1.12 V) can be
•
supplied from external via CN11 (voltage IN_1v12)
•
generated from the P3V3 power rail by use of the on-board voltage regulator IC16 (voltage reg_vcc_VDD)
•
generated by the on-chip Switching Voltage Regulator (SVR) in combination with device external power transistors
TR1, TR2 (voltage SVR_OUTPUT)
Note
The IN_1v12 and reg_vcc_VDD voltages have a level of typical 1.12 V, which is higher than the typical
device core voltage VDD of 1.09 V. The 30 mV difference is supposed to compensate voltage drops over the
power rails on the board, in particular over the jumpers.
Selection of the VDD source is achieved by use of the jumpers JP23 and JP16:
•
JP23[2-1]: VDD = 1.12 V (VDDs) from
−
JP16[2-1]: VDDs = reg_vcc_VDD from on-board voltage regulator IC16
−
JP16[2-3]: VDDs = IN_1v12 from external supply CN11
•
JP23[2-3]: VDD = 1.09 V (SVR_OUTPUT)
Note
If JP23[2-3]: VDD = 1.09 V (SVR_OUTPUT) is selected as core voltage it is not possible to operate the
device in DeepSTOP mode. Please refer to the precaution in 9.3 DeepSTOP Mode when using SVR for
details.
Figure 3.2 Device core voltage (VDD) selection
3.4
Current Measurement Bridges
The total current of the 5V0 and 3V3 power rails can be measured by replacing the jumpers JP4 and JP5 with a current
meter.
Accordingly, the total current via the A/D Converter's supply voltages A5V0 and A3V3 can be measured via the
jumpers JP30 and JP31 respectively.
The current of particular power supply pins of the device can be measured via their respective supply selection jumpers,
refer to Figure 3.1 Voltage distribution.
R20UT4545ED0102 Rev.1.02
May 27, 2021
3. Power Supply
Page 20 of 58
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