UPSD3212C, UPSD3212CV
Table 84. PSD MODULE Example, Typ. Power Calculation at V = 5.0V (Turbo Mode Off)
CC
Conditions
MCU Clock Frequency
= 12MHz
Highest Composite PLD input frequency
(Freq PLD)
= 8MHz
= 2MHz
MCU ALE frequency (Freq ALE)
% Flash memory
Access
= 80%
% SRAM access
% I/O access
= 15%
= 5% (no additional power above base)
Operational Modes
% Normal
= 40%
= 60%
% Power-down Mode
Number of product terms used
(from fitter report)
= 45 PT
% of total product terms = 45/182 = 24.7%
Turbo Mode
= Off
Calculation (using typical values)
I
total
= I (MCUactive) x %MCUactive + I (PSDactive) x %PSDactive + I (pwrdown) x %pwrdown
CC CC PD
CC
I
I
I
(MCUactive)
= 20mA
= 250µA
CC
(pwrdown)
PD
CC
(PSDactive)
= I (ac) + I (dc)
CC CC
= %flash x 2.5 mA/MHz x Freq ALE
+ %SRAM x 1.5 mA/MHz x Freq ALE
+ % PLD x (from graph using Freq PLD)
= 0.8 x 2.5 mA/MHz x 2MHz + 0.15 x 1.5 mA/MHz x 2MHz + 24 mA
= (4 + 0.45 + 24) mA
= 28.45mA
I
total
= 20mA x 40% + 28.45mA x 40% + 250µA x 60%
= 8mA + 11.38mA + 150µA
= 19.53mA
CC
This is the operating power with no Flash memory Erase or Program cycles in progress. Calculation is based on all I/
O pins being disconnected and I = 0 mA.
OUT
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STMICROELECTRONICS [ ST ]
