ADSP-2187L Analog Devices, ADSP-2187L Datasheet - Page 17

• Manufacturer Part Number: ADSP-2187L
• Description: DSP Microcomputer
• Manufacturer: Analog Devices

OUTPUT DRIVE CURRENTS
Figure 12 shows typical I-V characteristics for the output drivers
of the ADSP-2187L. The curves represent the current drive
capability of the output drivers as a function of output voltage.
Figure 13 shows the typical power-down supply current.
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:
•
•
•
•
REV. 0
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
1000
100
NOTES:
1. REFLECTS ADSP-2187L OPERATION IN LOWEST POWER MODE.
2. CURRENT REFLECTS DEVICE OPERATING WITH NO INPUT LOADS.
–20
–40
–60
–80
10
Figure 13. Power-Down Supply Current (Typical)
80
60
40
20
0
(SEE "SYSTEM INTERFACE" CHAPTER OF THE ADSP-2100 FAMILY
USER'S MANUAL FOR DETAILS.)
0
0
0
3.6V, –40 C
0.5
Figure 12. Typical Drive Currents
3.0V, +85 C
3.6V, –40 C
1
SOURCE VOLTAGE – Volts
3.3V, +25 C
25
3.0V, +85 C
TEMPERATURE – C
1.5
C V
3.3V, +25 C
2
DD
DD
2
= 3.3 V and t
2.5
55
f
3
3.5
CK
= 34.7 ns.
85
4
V
V
V
DD
DD
DD
= 3.6V
= 3.3V
= 3.0V
–17–
P
graph, see Figure 14.
(C
Address, DMS
Data Output, WR 9
RD
CLKOUT
Total power dissipation for this example is P
VALID FOR ALL TEMPERATURE GRADES.
1
2
3
4
INT
POWER REFLECTS DEVICE OPERATING WITH NO OUTPUT LOADS.
IDLE REFERS TO ADSP-2187L STATE OF OPERATION DURING EXECUTION OF IDLE
TYPICAL POWER DISSIPATION AT 3.3V V
I
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.
DD
MEASUREMENT TAKEN WITH ALL INSTRUCTIONS EXECUTING FROM INTERNAL
= internal power dissipation from Power vs. Frequency
V
DD
Total Power Dissipation = P
2
f ) is calculated for each output:
250
200
150
100
50
45
40
35
30
25
20
15
10
Figure 14. Power vs. Frequency
45
40
35
30
25
20
15
10
0
5
8
5
0
33.33
33.33
33.3
# of
Pins
8
1
1
144mW
112.2mW
87mW
25mW
21mW
10mW
9mW
23mW
2187L POWER, INTERNAL
V
DD
POWER, IDLE n MODES
= 3.3V
C
10 pF
10 pF
10 pF
10 pF
POWER, IDLE
FREQUENCY – MHz
FREQUENCY – MHz
FREQUENCY – MHz
23mW
V
V
V
V
DD
DD
DD
DD
DD
= 3.6V
= 3.3V
= 3.0V
= 3.6V
V
3.3
3.3
3.3
3.3
V
DD
AND 25 C EXCEPT WHERE SPECIFIED.
INT
DD
2
2
2
2
2
1, 2, 3
V
V
V
V
= 3.0V
32mW
+ (C
ADSP-2187L
168.3mW
f
33.3 MHz = 29.0 mW
16.67 MHz = 16.3 mW
16.67 MHz =
33.3 MHz =
1, 3, 4
132mW
216mW
3
12mW
13mW
35mW
30mW
32mW
INT
V
52
52
52
DD
DD
+ 50.7 mW.
IDLE
IDLE (16)
IDLE (128)
OR GND.
2
f )
50.7 mW
1.8 mW
3.6 mW