ADSP-2183
–24– REV. C
OUTPUT DRIVE CURRENTS
Figure 19 shows typical I-V characteristics for the output drivers
of the ADSP-2183. The curves represent the current drive
capability of the output drivers as a function of output voltage.
SOURCE VOLTAGE – V
100
–75
–150
0 5.25
SOURCE CURRENT – mA
0.75 1.50 2.25 3.00 3.75 4.50
75
–50
–100
–125
25
–25
50
0
–175
–200
3.0V, +85
°
C
3.3V, +25
°
C
3.6V, –40
°
C
3.0V, +85
°
C
3.3V, +25
°
C
3.6V, –40
°
C
Figure 19. Typical Drive Currents
NOTES:
1. REFLECTS ADSP-2183 OPERATION IN LOWEST POWER MODE.
(SEE "SYSTEM INTERFACE" CHAPTER OF THE ADSP-2100 FAMILY
USER'S MANUAL FOR DETAILS.)
2. CURRENT REFLECTS DEVICE OPERATING WITH NO INPUT LOADS.
V
DD
= 3.6V
V
DD
= 3.3V
V
DD
= 3.0V
TEMPERATURE – °C
CURRENT (LOG SCALE) – A
1000
100
0
08525 55
10
Figure 20. Power-Down Supply Current (Typical)
POWER DISSIPATION
To determine total power dissipation in a specific application,
the following equation should be applied for each output:
C × V
DD
2
× f
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
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
DD
= 3.3 V and t
CK
= 30.0 ns.
Total Power Dissipation = P
INT
+ (C × V
DD
2
× f )
P
INT
= internal power dissipation from Power vs. Frequency
graph (Figure 20).
(C × V
DD
2
× f ) is calculated for each output:
# of
Pins × C × V
DD
2
× f
Address, DMS 8 × 10 pF × 3.3
2
V × 33.3 MHz = 29.0 mW
Data Output, WR 9 × 10 pF × 3.3
2
V × 16.67 MHz = 16.3 mW
RD 1 × 10 pF × 3.3
2
V × 16.67 MHz = 1.8 mW
CLKOUT 1 × 10 pF × 3.3
2
V × 33.3 MHz = 3.6 mW
50.7 mW
Total power dissipation for this example is P
INT
+ 50.7 mW.
1/t
CK
– MHz
220
160
115
28 5232 36 40 44 48
205
175
145
130
190
100
85
70
2183 POWER, INTERNAL
1, 3, 4
V
DD
= 3.6V
V
DD
= 3.3V
V
DD
= 3.0V
184mW
150mW
120mW
110mW
90mW
72mW
1/t
CK
– MHz
50
25
10
28
5232
36 40 44 48
45
30
20
15
40
35
5
0
POWER, IDLE
1, 2, 3
V
DD
= 3.6V
V
DD
= 3.3V
V
DD
= 3.0V
38mW
30mW
24mW
27mW
20mW
15mW
1/t
CK
– MHz
32
22
16
4428 32 36 40
30
24
20
18
28
26
14
12
10
8
POWER, IDLE n MODES
3
48 52
IDLE
IDLE (16)
IDLE (128)
30mW
13.8mW
13mW
20mW
11mW
10.6mW
VALID FOR ALL TEMPERATURE GRADES.
1
POWER REFLECTS DEVICE OPERATING WITH NO OUTPUT LOADS.
2
IDLE REFERS TO ADSP-2183 STATE OF OPERATION DURING EXECUTION OF IDLE
INSTRUCTION. DEASSERTED PINS ARE DRIVEN TO EITHER V
DD
OR GND.
3
TYPICAL POWER DISSIPATION AT 3.3V V
DD
AND 25ⴗC EXCEPT WHERE SPECIFIED.
4
I
DD
MEASUREMENT TAKEN WITH ALL INSTRUCTIONS EXECUTING FROM INTERNAL
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.
Figure 21. Power vs. Frequency
