MC34025DW ON Semiconductor, MC34025DW Datasheet - Page 12

• Manufacturer Part Number: MC34025DW
• Description: IC CTRLR PWM DBL END HF 16SOIC
• Manufacturer: ON Semiconductor

Specifications of MC34025DW

• Pwm Type: Voltage/Current Mode
• Number Of Outputs: 2
• Frequency - Max: 1MHz
• Duty Cycle: 45%
• Voltage - Supply: 10 V ~ 30 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Frequency-max: 1MHz
• Duty Cycle (max): 45 %
• Output Voltage: 5.05 V to 5.15 V
• Output Current: 500 mA
• Mounting Style: SMD/SMT
• Switching Frequency: 1000 KHz
• Operating Supply Voltage: 30 V
• Maximum Operating Temperature: + 70 C
• Fall Time: 30 ns
• Minimum Operating Temperature: 0 C
• Rise Time: 30 ns
• Synchronous Pin: Yes
• Topology: Half-Bridge, Push-Pull
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: MC34025DWOS

This method of slope compensation is easy to implement, however, it is noise sensitive. Capacitor C
signal is added to the current signal by a voltage divider consisting of resistors R
When only one output is used, this method of slope compensation can be used and it is relatively noise immune. Resistor R
capacitor C
can assume that its charge is linear. First choose C
pulse at the ramp input at the end of every cycle. The charge current I
R
Output
M
= V
CC
/I
M
M
R
.
M
provide the added slope necessary. By choosing R
C
M
Current Sense
Transformer
R
C
R
w
f
f
Figure 30. Current Mode Master/Slave Operation Over Short Distances
Ramp
Input
3
7
Figure 29. Keeps Fig numbering sequence correct
Figure 29A. Slope Compensation (Noise Sensitive)
1.25 V
Figure 29B. Slope Compensation (Noise Immune)
Oscillator
Current Sense
Information
C
M
T
, then R
4
5
6
R
2
http://onsemi.com
M
R
C
C
1
can be adjusted to achieve the required slope. The diode provides a reset
1
T
M
and C
12
4
5
6
7
3
R
M
T
can be calculated by I
V
M
ref
1.25 V
with a larger time constant than the switching frequency, you
Current Sense
Resistor
1
4
5
6
Oscillator
and R
2
.
Oscillator
M
R
f
= C
C
M
Output
1
M
provides AC coupling. The oscillator
S
R
e
C
M
. Then R
f
Ramp
7
3
Input
M
can be calculated by
1.25 V
M
and