UC3842B, 43B UC2842B, 43B
ELECTRICAL CHARACTERISTICS
(VCC = 15 V [Note 2], RT = 10 k, CT = 3.3 nF, for typical values TA = 25°C, for min/max values TA
is the operating ambient temperature range that applies [Note 3], unless otherwise noted.)
UC284XB
Characteristics
PWM SECTION
Duty Cycle
Maximum (UC284XB, UC384XB)
Maximum
(UC384XBV)
Minimum
TOTAL DEVICE
Power Supply Current
Startup (VCC = 6.5 V for UCX843B,
Startup
(VCC 14 V for UCX842B, BV)
Operating (Note 2)
Power Supply Zener Voltage (ICC = 25 mA)
ICC + IC
–
–
VZ
30
0.3
12
36
0.5
17
–
–
–
30
0.3
12
36
0.5
17
–
V
mA
%
DC(max)
DC(min)
94
–
–
96
–
–
–
–
0
94
93
–
96
96
–
–
–
0
Symbol
Min
Typ
Max
Min
UC384XB, BV
Typ
Max
Unit
NOTES:
2. Adjust VCC above the Startup threshold before setting to 15 V.
3. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
Tlow = 0°C for UC3842B, UC3843B
Thigh = +70°C for UC3842B, UC3843B
Tlow =
–25°C for UC2842B, UC2843B
Thigh =
+85°C for UC2842B, UC2843B
Tlow =
–40°C for UC3842BV, UC3843BV
Thigh =
+105°C for UC3842BV, UC3843BV
Figure 1. Timing Resistor
versus Oscillator Frequency
80
% DT, PERCENT OUTPUT DEADTIME
50
R T, TIMING RESISTOR (k
Ω
)
20
8.0
5.0
2.0
0.8
10 k
VCC = 15 V
TA = 25°C
20 k
50 k
100 k
200 k
500 k
fOSC, OSCILLATOR FREQUENCY (kHz)
1.0 M
100
Figure 2. Output Deadtime
versus Oscillator Frequency
1. CT = 10 nF
50 2. CT = 5.0 nF
3. CT = 2.0 nF
4. CT = 1.0 nF
20 5. CT = 500 pF
6. CT = 200 pF
10 7. CT = 100 pF
5.0
2.0
1.0
10 k
20 k
4
3
2
1
5
6
7
VCC = 15 V
TA = 25°C
50 k
100 k
200 k
500 k
fOSC, OSCILLATOR FREQUENCY (kHz)
1.0 M
Figure 3. Oscillator Discharge Current
versus Temperature
9.0
I dischg , DISCHARGE CURRENT (mA)
VCC = 15 V
VOSC = 2.0 V
8.5
D max , MAXIMUM OUTPUT DUTY CYCLE (%)
100
90
80
70
60
50
40
0.8
Figure 4. Maximum Output Duty Cycle
versus Timing Resistor
Idischg = 7.5 mA
8.0
Idischg = 8.8 mA
7.5
VCC = 15 V
CT = 3.3 nF
TA = 25°C
5.0 6.0 7.0 8.0
7.0
– 55
– 25
0
25
50
75
TA, AMBIENT TEMPERATURE (°C)
100
125
1.0
2.0
3.0
4.0
RT, TIMING RESISTOR (kΩ)
4
MOTOROLA ANALOG IC DEVICE DATA
MOTOROLA [ MOTOROLA, INC ]
