ADSP-2104 Analog Devices, ADSP-2104 Datasheet - Page 18

• Manufacturer Part Number: ADSP-2104
• Description: Low Cost DSP Microcomputers
• Manufacturer: Analog Devices

ADSP-2104/ADSP-2109
SPECIFICATIONS (ADSP-2104L /ADSP-2109L)
POWER DISSIPATION EXAMPLE
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 ADSP-2104L application where external data memory is
used and no other outputs are active, power dissipation is
calculated as follows:
Assumptions:
•
•
•
•
P
(C
Output
Address, DMS 8
Data, WR
RD
CLKOUT
Total power dissipation for this example = P
ENVIRONMENTAL CONDITIONS
Ambient Temperature Rating:
Package
PLCC
INT
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
T
T
PD = Power Dissipation in W
CA
JA
JC
AMB
CASE
= internal power dissipation (from Figure 13).
V
= Thermal Resistance (Junction-to-Ambient)
= Thermal Resistance (Junction-to-Case)
DD
= Thermal Resistance (Case-to-Ambient)
Total Power Dissipation = P
= T
= Case Temperature in C
2
CASE
f ) is calculated for each output:
# of
Pins
9
1
1
– (PD
27 C/W
JA
C
10 pF
10 pF
10 pF
10 pF
C
CA
)
V
DD
DD
3.3
3.3
3.3
3.3
2
V
INT
= 3.3 V and t
DD
2
2
2
2
f
V
V
V
V
2
+ (C
16 C/W
JC
10 MHz = 8.71 mW
5 MHz = 4.90 mW
5 MHz = 0.55 mW
10 MHz = 1.09 mW
f
INT
V
DD
CK
+ 15.25 mW.
2
= 100 ns.
15.25 mW
f )
11 C/W
CA
–18–
CAPACITIVE LOADING
Figures 14 and 15 show capacitive loading characteristics.
Figure 15. Typical Output Valid Delay or Hold vs. Load
Capacitance, C
Figure 14. Typical Output Rise Time vs. Load Capacitance, C
(at Maximum Ambient Operating Temperature)
NOMINAL
L
(at Maximum Ambient Operating Temperature)
+8
+6
+4
+2
–2
30
25
20
15
10
5
25
25
V
DD
= 3.0V
50
50
V
DD
75
C
75
C
= 3.0V
L
L
– pF
– pF
100
100
125
125
150
150
REV. 0
L