ST & T UPSD3212C - Manual (Page 129)

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uPSD3212A, uPSD3212C, uPSD3212CV
Table 104. PSD MODULE Example, Typ. Power Calculation at V
CC
= 5.0V (Turbo Mode Off)
Conditions
MCU Clock Frequency = 12MHz
Highest Composite PLD input frequency
(Freq PLD) = 8MHz
MCU ALE frequency (Freq ALE) = 2MHz
% Flash memory Access = 80%
% SRAM access = 15%
% I/O access = 5% (no additional power above base)
Operational Modes
% Normal = 40%
% Power-down Mode = 60%
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
CC
total = I
CC
(MCUactive) x %MCUactive + I
CC
(PSDactive) x %PSDactive + I
PD
(pwrdown) x %pwrdown
I
CC
(MCUactive) = 20mA
I
PD
(pwrdown) = 250µA
I
CC
(PSDactive) = I
CC
(ac) + I
CC
(dc)
= %flash x 2.5mA/MHz x Freq ALE
+ %SRAM x 1.5mA/MHz x Freq ALE
+ % PLD x (from graph using Freq PLD)
= 0.8 x 2.5mA/MHz x 2MHz + 0.15 x 1.5mA/MHz x 2MHz + 24mA
= (4 + 0.45 + 24) mA
= 28.45mA
I CC total = 20mA x 40% + 28.45mA x 40% + 250µA x 60%
= 8mA + 11.38mA + 150µA
= 19.53mA
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
OUT
= 0mA.