Data Sheet
AZ3842/3/4/5
Advanced Analog Circuits
CURRENT MODE PWM CONTROLLER
Electrical Characteristics (Continued)
Figure 4 is the basic test circuit for AZ384x. In testing, the high peak currents associated with capacitive loads necessitate
careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The
transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.
Typical Performance Characteristics
100k
50K
30
10
3
1
10k
5K
0.3
100
1k
10k
100k
1M
1
10
100
22
47
2.2
4.7
Frequency (Hz)
Timing Capacitor (nF)
Figure 6. Timing Resistor vs. Frequency
Figure 5. Oscillator Dead Time vs. Timing Capacitor
1.0
0.9
0.8
0.7
0.6
0.5
0.4
5.015
VCC=15V, IO=1mA
5.010
AZ3842
5.005
5.000
4.995
4.990
4.985
4.980
-40
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
Ambient Temperature (oC)
Ambient Temperature (oC)
Figure 7. Reference Voltage vs. Ambient Temperature
Figure 8. Start-up Current vs. Ambient Temperature
March 2003
Rev: 1.0
7
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
