Datasheet
ADSP-21160M
–42– REV. 0
Output Drive Currents
Figure 29 shows typical I–V characteristics for the output drivers of the ADSP-21160M. The curves represent the current
drive capability of the output drivers as a function of output voltage.
Power Dissipation
Total power dissipation has two components, one due to internal circuitry and one due to the switching of external output
drivers.
Internal power dissipation is dependent on the instruction execution sequence and the data operands involved. Using the
current specifications (I
DDINPEAK
, I
DDINHIGH
, I
DDINLOW
, I
DDIDLE
) from Electrical Characteristics on page 13 and the current-ver-
sus-operation information in Table 29, engineers can estimate the ADSP-21160M’s internal power supply (V
DDINT
) input
current for a specific application, according to the following formula:
The external component of total power dissipation is caused by the switching of output pins. Its magnitude depends on:
• the number of output pins that switch during each cycle (O)
• the maximum frequency at which they can switch (f)
• their load capacitance (C)
• their voltage swing (VDD)
and is calculated by:
P
EXT
= O × C × V
DD
2
× f
Figure 29. ADSP-21160M Typical Drive Currents
#
$
$
B*B* B* B*
#
#
$
1
$
$)
$
$
$
)
=B'@G
=B@*G
=B@)*G
=B' @G
=B@*G
=B@)*G
% Peak I
DDINPEAK
×
% High I
DDINHIGH
×
% Low I
DDINLOW
×
+ % Idle I
DDIDLE
×
I
DDINT
--------------------------------------------------