TB62802F Datasheet, PDF (7/19 Pages) Toshiba Semiconductor – CCD Clock Drivers

Reference Characteristics
Load Capacitance vs. Power Dissipation
1.2
1
0.8
0.6
Drive frequency: 25 MHz
(all bits are driven at the same frequency)
0.4
Supply voltage: 5.0 V
Light load capacitance: 20 pF
Light load internal equivalent capacitance:
18 pF
0.2
Heavy load internal equivalent capacitance:
57 pF
Ambient temperature: 25°C
0
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
Load capacitance pF
TB62802F
Power Dissipation and Junction Temperature (reference value)
1.00 _Condition:
120
(1) Power dissipation
0.90 _{IC internal equivalent capacitance}
(2) Junction temperature
Ta = 25°C
0.80
CCD input capacitance
Heavy load = 57 pF
Light load = 18 pF
Main clock = 250 pF
θja = 83.3°C/W
(typical value for the IC itself)
100
0.70
Control clock = 20 pF
Driver supply voltage = 5.0 V
80
0.60
Driver output amplitude = 5.0 V
The main clock and control clock oscillate at
0.50 ^{the same frequency.}
60
0.40
40
0.30
0.20
20
Power dissipation
0.10
Junction temperature
0.00
0
1.0
3.0
5.0
7.0 9.0 11.0 13.0 15.0 17.0 19.0 21.0 23.0 25.0
Drive frequency MHz
Thermal Design
The junction temperature is expressed as follows:
Tj = Ta + (θjc + θca) × Pd
= Ta + θja × Pd
Tj: Junction temperature
Ta: Ambient temperature
θjc: Thermal resistance from chip to case (a specific value not affected by environment)
θja: Thermal resistance from chip to ambient temperature (affected by environment)
Pd: Power dissipation when driving external load
Here, the thermal performance of the heat dispersion on the PCB and of the ambient temperature setting
should be so designed that the calculated value is within the specified range.
7
2006-06-13