MC34025DWG ON Semiconductor, MC34025DWG Datasheet - Page 10

• Manufacturer Part Number: MC34025DWG
• Description: IC CTRLR PWM DBL END HF 16SOIC
• Manufacturer: ON Semiconductor

Specifications of MC34025DWG

• 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: Lead free / RoHS Compliant
• Other names: MC34025DWGOS

DIP/SOIC
In voltage mode operation, the control range on the output of
the Error Amplifier from 0% to 90% duty cycle is from 2.25 V
to 4.05 V.
Pin No.
10
12
13
14
15
16
11
1
2
3
4
5
6
7
8
9
Feedback Input
Output Voltage
Figure 22. Voltage Mode Operation
Error Amp Inverting
Input
Error Amp
Noninverting Input
Error Amp Output
Clock
R
C
Ramp Input
Soft−Start
Current
Limit/Shutdown
Ground
Output A
Power Ground
V
Output B
V
V
C
C
CC
ref
T
T
T
Function
V
ref
4
5
6
7
3
1
2
This pin is usually used for feedback from the output of the power supply.
This pin is used to provide a reference in which an error signal can be produced on the output of the
error amp. Usually this is connected to V
This pin is provided for compensating the error amp for poles and zeros encountered in the power
supply system, mostly the output LC filter.
This is a bidirectional pin used for synchronization.
The value of R
In conjunction with R
push−pull output, each output runs at one−half the frequency set at this pin.
For voltage mode operation this pin is connected to C
connected through a filter to the current sensing element.
A capacitor at this pin sets the Soft−Start time.
This pin has two functions. First, it provides cycle−by−cycle current limiting. Second, if the current is
excessive, this pin will reinitiate a Soft−Start cycle.
This pin is the ground for the control circuitry.
This is a high current totem pole output.
This is a separate power ground return that is connected back to the power source. It is used to
reduce the effects of switching transient noise on the control circuitry.
This is a separate power source connection for the outputs that is connected back to the power
source input. With a separate power source connection, it can reduce the effects of switching
transient noise on the control circuitry.
This is a high current totem pole output.
This pin is the positive supply of the control IC.
This is a 5.1 V reference. It is usually connected to the noninverting input of the error amplifier.
1.25 V
Oscillator
PIN FUNCTION DESCRIPTION
T
sets the charge current through timing Capacitor, C
T
http://onsemi.com
, the timing Capacitor sets the switching frequency. Because this part is a
10
In current mode control, an RC filter should be placed at the
ramp input to filter the leading edge spike caused by turn−on of
a power MOSFET.
Sense Element
From Current
ref
, however an external reference can also be used.
Feedback Input
Output Voltage
Description
Figure 23. Current Mode Operation
T
. For current mode operation this pin is
C
T
V
ref
4
5
6
7
3
1
2
T
.
1.25 V
Oscillator