ADSP-2171 Analog Devices, ADSP-2171 Datasheet - Page 29

• Manufacturer Part Number: ADSP-2171
• Description: ADSP-2100 Family DSP Microcomputers
• Manufacturer: Analog Devices

REV. A
ADSP-2171/ADSP-2172
ENVIRONMENTAL CONDITIONS
Ambient Temperature Rating:
Package
TQFP
PQFP
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:
•
•
•
•
P
graph (Figure 18).
(C
Address, DMS
Data Output, WR 9
RD
CLKOUT
Total power dissipation for this example is P
INT
T
T
PD = Power Dissipation in W
External data memory is accessed every cycle with 50% of the
address pins switching.
External data memory writes occur every other cycle with
50% of the data pins switching.
Each address and data pin has a 10 pF total load at the pin.
The application operates at V
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
Total Power Dissipation = P
= T
= Case Temperature in C
2
CASE
f ) is calculated for each output:
– (PD
# of
Pins
8
1
1
50 C/W
41 C/W
JA
C
10 pF
10 pF
10 pF
10 pF
C
CA
)
V
DD
DD
V
5
5
5
5
2
2
2
2
2
DD
= 5.0 V and t
INT
V
V
V
V
2 C/W
10 C/W
2
JC
f
+ (C
f
33.3 MHz
16.67 MHz = 37.5 mW
16.67 MHz =
33.3 MHz
INT
V
DD
CK
+ 116.6 mW.
2
= 30 ns.
= 66.6 mW
=
f )
116.6 mW
48 C/W
31 C/W
CA
4.2 mW
8.3 mW
–29–
ADSP-2171/ADSP-2172/ADSP-2173
VALID FOR ALL TEMPERATURE GRADES.
1
2
3
EXECUTION OF IDLE INSTRUCTION. DEASSERTED PINS ARE
DRIVEN TO EITHER V
OPERATING WITH CLKOUT DISABLED.
OF IDLE N INSTRUCTION (CLOCK FREQUENCY REDUCTION).
POWER REFLECTS DEVICE OPERATING WITH CLKOUT DISABLED.
POWER REFLECTS DEVICE OPERATING WITH NO OUTPUT LOADS.
IDLE REFERS TO ADSP-2171 STATE OF OPERATION DURING
TYPICAL POWER DISSIPATION AT 5.0V V
400
375
350
325
300
275
250
225
200
175
150
125
85
80
75
70
65
60
55
50
45
40
35
30
72
68
64
60
56
52
48
44
40
36
32
28
24
20
16
110mW
186mW
148mW
37mW
26mW
37mW
23mW
48mW
20mW
13
13
13
Figure 18. Power vs. Frequency
15
15
15
POWER, IDLE n MODES
17
POWER, INTERNAL
17
17
V
V
DD
DD
POWER, IDLE
DD
19
19
19
OR GND. POWER REFLECTS DEVICE
= 5.5V
= 5.5V
1
V
V
1
1
/ t
DD
DD
21
/ t
/ t
21
21
CK
V
CK
CK
V
= 5.0V
= 5.0V
DD
23
– MHz
DD
23
23
– MHz
– MHz
= 4.5V
= 4.5V
25
25
25
1, 2
27
27
27
DD
1
29
DURING EXECUTION
29
29
382mW
229mW
301mW
48mW
64mW
82mW
82mW
3
31
31
31
31mW
28mW
64mW
33
33
33
IDLE;
IDLE (16)
IDLE (128)