ADSP-2115_15 Datasheet, PDF (19/64 Pages) Analog Devices – ADSP-2100 Family DSP Microcomputers

ADSP-21xx
SPECIFICATIONS (ADSP-2101/2105/2115/2161/2163)
POWER DISSIPATION EXAMPLE
To determine total power dissipation in a specific application,
the following equation should be applied for each output:
CAPACITIVE LOADING
Figures 12 and 13 show capacitive loading characteristics for the
ADSP-2101, ADSP-2105, ADSP-2115, and ADSP-2161/2163.
C × V_DD² × f
C = load capacitance, f = output switching frequency.
Example:
In an ADSP-2101 application where external data memory is
used and no other outputs are active, power dissipation is
calculated as follows:
8
7
V_DD = 4.5V
6
5
Assumptions:
4
• 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 = 5.0 V and t_CK = 50 ns.
Total Power Dissipation = P_INT + (C × V_DD2 × f )
3
2
1
0
0 25 50 75 100 125 150 175
C_L – pF
P_INT = internal power dissipation (from Figure 11).
(C × V_DD2 × f ) is calculated for each output:
Figure 12. Typical Output Rise Time vs. Load Capacitance, C_L
(at Maximum Ambient Operating Temperature)
Output
# of
Pins × C
× V_DD2 × f
Address, DMS 8
Data, WR
9
RD
1
CLKOUT 1
× 10 pF
× 10 pF
× 10 pF
× 10 pF
× 5² V
× 5² V
× 5² V
× 5² V
× 20 MHz = 40.0 mW
× 10 MHz = 22.5 mW
× 10 MHz = 2.5 mW
× 20 MHz = 5.0 mW
70.0 mW
Total power dissipation for this example = P_INT + 70.0 mW.
ENVIRONMENTAL CONDITIONS
Ambient Temperature Rating:
T_AMB = T_CASE – (PD × θ_CA)
T_CASE = Case Temperature in °C
PD = Power Dissipation in W
θ_CA = Thermal Resistance (Case-to-Ambient)
θ_JA = Thermal Resistance (Junction-to-Ambient)
θ_JC = Thermal Resistance (Junction-to-Case)
5
4
3
V_DD = 4.5V
2
1
0
–1
–2
–3
0 25 50 75 100 125 150 175
C_L – pF
Figure 13. Typical Output Valid Delay or Hold vs. Load
Capacitance, C_L (at Maximum Ambient Operating Temperature)
Package
PGA
PLCC
PQFP
TQFP
θ_JA
18°C/W
27°C/W
60°C/W
60°C/W
θ_JC
9°C/W
16°C/W
18°C/W
18°C/W
θ_CA
9°C/W
11°C/W
42°C/W
42°C/W
REV. B
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