ADSP-2188MKCA-300 データシートの表示（PDF） - Analog Devices
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ADSP-2188MKCA-300 Datasheet PDF : 40 Pages
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FREQUENCY DEPENDENCY FOR TIMING
SPECIFICATIONS
tCK is defined as 0.5 tCKI. The ADSP-2188M uses an input clock
with a frequency equal to half the instruction rate. For example,
a 37.50 MHz input clock (which is equivalent to 26.6 ns) yields
a 13.3 ns processor cycle (equivalent to 75 MHz). tCK values
within the range of 0.5 tCKI period should be substituted for all
relevant timing parameters to obtain the specification value.
Example: tCKH = 0.5 tCK – 2 ns = 0.5 (15 ns) – 2 ns = 5.5 ns
ENVIRONMENTAL CONDITIONS1
Rating
Description
Symbol LQFP
Thermal Resistance
θCA
(Case-to-Ambient)
Thermal Resistance
θJA
(Junction-to-Ambient)
Thermal Resistance
θJC
(Junction-to-Case)
48°C/W
50°C/W
2°C/W
NOTE
1Where the Ambient Temperature Rating (TAMB) is:
TAMB = TCASE – (PD × θCA)
TCASE = Case Temperature in °C
PD = Power Dissipation in W
Mini-BGA
63.3°C/W
70.7°C/W
7.4°C/W
POWER DISSIPATION
To determine total power dissipation in a specific application,
the following equation should be applied for each output:
C
×
V2
DD
×
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.
ADSP-2188M
• Each address and data pin has a 10 pF total load at the pin.
• The application operates at VDDEXT = 3.3 V and tCK = 30 ns.
Total Power Dissipation = PINT + (C × VDDEXT2 × f )
PINT = internal power dissipation from Power vs. Frequency
graph (Figure 15).
(C × VDDEXT2 × f ) is calculated for each output:
Parameters
Address
Data Output, WR
RD
CLKOUT, DMS
# of
Pins
7
9
1
2
؋ C ؋ VDDEXT2 ؋ f
PD
pF V
MHz mW
10 3.32
10 3.32
10 3.32
10 3.32
16.67 12.7
16.67 16.3
16.67 1.8
33.3 7.2
38.0
Total power dissipation for this example is PINT + 38.0 mW.
Output Drive Currents
Figure 14 shows typical I-V characteristics for the output drivers
on the ADSP-2188M. The curves represent the current drive
capability of the output drivers as a function of output voltage.
80
60
VOH
VDDEXT = 3.6V @ –40؇C
40
VDDEXT = 3.3V @ +25؇C
20
VDDEXT = 2.5V @ +85؇C
0
–20
VDDEXT = 3.6V @ –40؇C
–40
VOL
VDDEXT = 2.5V @ +85؇C
VDDEXT = 3.3V @ +25؇C
–60
–80
0
0.5
1.0 1.5
2.0
2.5
3.0 3.5
4.0
SOURCE VOLTAGE – V
Figure 14. Typical Output Driver Characteristics
REV. 0
–21–
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