EF6805U3 Datasheet, PDF (3/31 Pages) STMicroelectronics – 8-BIT MICROCOMPUTER UNIT

EF6805U3
POWER CONSIDERATIONS
The average chip-junction temperature, TJ, in C can
be obtained from :
T_J = T_A + (P_D.J_A) (1)
Where :
TA = Ambient Temperature, C
J_A = Package Thermal Resistance, Junction-to-Am-
bient, C/W
PD = PINT + PPORT
PINT = ICC x VCC, Watts - Chip Internal Power
P_PORT = Port Power Dissipation, Watts - User De-
termined
For most applications PPORT PINT and can be ne-
glected. PPORT may become significant if the device
is configured to drive Darlington bases or sink LED
loads.
An approximate relationship between P_D and T_J (if
P_PORT is neglected) is :
PD = K + (TJ + 273C) (2)
Solving equations 1 and 2 for K gives :
K = P_D.(T_A + 273C) + J_A.P_D2 (3)
Where K is a constant pertaining to the particular
part. K can be determined from equation 3 by mea-
suring PD (at equilibrium) for a known TA. Using this
value of K the values of PD and TJ can be obtained
by solving equations (1) and (2) iteratively for any
value of T_A.
ELECTRICAL CHARACTERISTICS(V _CC = + 5.25Vdc ± 0.5Vdc, V_{S S} = 0Vdc, T_A = T_L to T_H unless
otherwise noted)
Symbol
Parameter
Min.
V _IH
Input High Voltage
RESET (4.75 ≤ V_CC ≤ 5.75)
(V _CC < 4.75)
INT (4.75 ≤ V_CC ≤ 5.75)
(V_CC < 4.75)
All Other (except timer)
4.0
V_CC – 0.5
4.0
V_CC – 0.5
2.0
V _IH
Input High Voltage Timer
Timer Mode
2.0
Self-check Mode
9.0
V _IL
Input Low Voltage
RESET
V_SS
INT
V_SS
All Other
V_SS
V_{IRE S +} RESET Hystereris Voltages (see figures 10, 11 and 12)
V _{IRE S –}
”Out of Reset”
2.1
”Into Reset”
0.8
V _{IN T}
INT Zero Crossing Input Voltage, Through a
2
Capacitor
P_D
Power Dissipation - (no port loading, V_CC = 5.75V)
T_A = 0°C
T_A = – 40°C
C_in
Input Capacitance
EXTAL
All Other
V_{L V R}
VL_{V I}
I_in
Low Voltage Recover
Low Voltage Inhibit
Input Current
TIMER (V_in = 0.4V)
INT (V_in = 2.4V to V_CC)
EXTAL (V_in = 2.4V to V_CC - crystal option)
(V_in = 0.4V - crystal option)
RESET (V_in = 0.8V) - External Capacitor Charging
Current
2.75
– 40.0
* Due to internal biasing this input (when unused) floats to approximately 2.2V.
Typ.
•
•
10.0
•
520
580
25
10
3.75
20
Max.
V _CC
V _CC
V _CC
V _CC
V _CC
V_CC + 1.0
15.0
0.8
1.5
0.8
4.0
2.0
4
Unit
V
V
V
V
V_{ac p-p}
mW
740
800
pF
4.75
V
4.70
V
µA
20
50
10
– 1600
– 40
3/31