adsp2185 Analog Devices, Inc., adsp2185 Datasheet - Page 15

• Manufacturer Part Number: adsp2185
• Description: Dsp Microcomputer
• Manufacturer: Analog Devices, Inc.

ENVIRONMENTAL CONDITIONS
Ambient Temperature Rating:
Package
TQFP
POWER DISSIPATION
To determine total power dissipation in a specific application,
the following equation should be applied for each output:
C = load capacitance, f = output switching frequency.
Example:
In an application where external data memory is used and no
other outputs are active, power dissipation is calculated as follows:
Assumptions:
• External data memory is accessed every cycle with 50% of the
• External data memory writes occur every other cycle with
• Each address and data pin has a 10 pF total load at the pin.
• The application operates at V
P
graph (Figure 8).
(C
Address, DMS
Data Output, WR 9
RD
CLKOUT
Total power dissipation for this example is P
REV. 0
INT
T
T
PD = Power Dissipation in W
address pins switching.
50% of the data pins switching.
CA
JA
JC
AMB
CASE
= internal power dissipation from Power vs. Frequency
V
= Thermal Resistance (Junction-to-Ambient)
= Thermal Resistance (Junction-to-Case)
= Thermal Resistance (Case-to-Ambient)
DD
= T
= Case Temperature in C
Total Power Dissipation = P
2
CASE
f) is calculated for each output:
– (PD x
# of
Pins
8
1
1
50 C/W
JA
10 pF
10 pF
10 pF
10 pF
C
C
CA
)
V
DD
DD
5
5
5
5
V
2
2
2
2
2
= 5.0 V and t
DD
INT
V
V
V
V
f
2
2 C/W
+ (C
JC
f
33.3 MHz = 66.6 mW
16.67 MHz = 37.5 mW
16.67 MHz = 4.2 mW
33.3 MHz =
INT
V
DD
+ 116.6 mW.
CK
2
= 30 ns.
116.6 mW
f)
48 C/W
8.3 mW
CA
–15–
VALID FOR ALL TEMPERATURE GRADES.
1
2
3
4
INSTRUCTION. DEASSERTED PINS ARE DRIVEN TO EITHER V
MEMORY. 50% OF THE INSTRUCTIONS ARE MULTIFUNCTION (TYPES 1, 4, 5, 12, 13, 14),
30% ARE TYPE 2 AND TYPE 6, AND 20% ARE IDLE INSTRUCTIONS.
POWER REFLECTS DEVICE OPERATING WITH NO OUTPUT LOADS.
IDLE REFERS TO ADSP-2185 STATE OF OPERATION DURING EXECUTION OF IDLE
TYPICAL POWER DISSIPATION AT 5.0V V
I
DD
MEASUREMENT TAKEN WITH ALL INSTRUCTIONS EXECUTING FROM INTERNAL
440
420
400
380
360
340
320
300
280
260
240
220
200
95
90
85
80
75
70
65
60
55
50
45
40
75
70
65
60
55
50
45
40
35
30
25
28
28
28
Figure 8. Power vs. Frequency
34mW
56mW
40mW
56mW
36mW
349mW
277mW
214mW
75mW
2185 POWER, INTERNAL
29
29
29
POWER, IDLE n MODES
POWER, IDLE
30
30
30
V
V
V
DD
DD
DD
V
V
V
1/
1/f
1/f
DD
DD
DD
t
CK
CK
CK
= 5.5V
= 5.0V
= 4.5V
= 5.5V
= 5.0V
= 4.5V
31
31
31
– MHz
– MHz
– MHz
DD
AND 25 C EXCEPT WHERE SPECIFIED.
32
32
32
1, 2
1, 3, 4
396mW
315mW
243mW
33
83mW
62mW
45mW
62mW
38mW
36mW
3
33
33
ADSP-2185
34
34
34
DD
IDLE
IDLE (16)
IDLE (128)
OR GND.