© Semiconductor Components Industries, LLC, 2012
October, 2012 − Rev. 9
1 Publication Order Number:
MC34025/D
MC34025, MC33025
High Speed Double-Ended
PWM Controller
The MC34025 series are high speed, fixed frequency, double−ended
pulse width modulator controllers optimized for high frequency
operation. They are specifically designed for Off−Line and
DC−to−DC converter applications offering the designer a cost
effective solution with minimal external components. These
integrated circuits feature an oscillator, a temperature compensated
reference, a wide bandwidth error amplifier, a high speed current
sensing comparator, steering flip−flop, and dual high current totem
pole outputs ideally suited for driving power MOSFETs.
Also included are protective features consisting of input and
reference undervoltage lockouts each with hysteresis, cycle−by−cycle
current limiting, and a latch for single pulse metering.
The flexibility of this series allows it to be easily configured for
either current mode or voltage mode control.
Features
• 50 ns Propagation Delay to Outputs
• Dual High Current Totem Pole Outputs
• Wide Bandwidth Error Amplifier
• Fully−Latched Logic with Double Pulse Suppression
• Latching PWM for Cycle−By−Cycle Current Limiting
• Soft−Start Control with Latched Overcurrent Reset
• Input Undervoltage Lockout with Hysteresis
• Low Startup Current (500 mA Typ)
• Internally Trimmed Reference with Undervoltage Lockout
• 45% Maximum Duty Cycle (Externally Adjustable)
• Precision Trimmed Oscillator
• Voltage or Current Mode Operation to 1.0 MHz
• Functionally Similar to the UC3825
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Figure 1. Simplified Application
Error
Amp
Oscillator
4
16
V
ref
Clock
5
6
R
T
C
T
3
7
Ramp
Error Amp
Output
2
Inverting
Input
1
8
Soft-Start
Soft-Start
Latching
PWM and
Steering
Flip Flop
Ground
10
9
Current
Limit/
Shutdown
Output B
14
V
C
13
V
CC
15
UVLO
5.1V
Reference
11
Noninverting
Input
Power
Ground
12
Output A
This device contains 227 active transistors.
PDIP−16
P SUFFIX
CASE 648
1
16
SO−16WB
DW SUFFIX
CASE 751G
1
16
MARKING
DIAGRAMS
PIN CONNECTIONS
1
16
MC3x025P
AWLYYWWG
11
5
2
1
Error Amp
Noninverting Input
Current Limit/
Shutdown
Ground
Output A
Power Ground
V
C
Output B
V
CC
V
ref
9
10
12
13
14
15
16
8
7
6
4
3
(Top View)
Soft-Start
Ramp
C
T
R
T
Clock
Error Amp Output
Error Amp
Inverting Input
http://onsemi.com
*For additional information on our Pb−Free strategy
and soldering details, please download the
ON Semiconductor Soldering and Mounting
Techniques Reference Manual, SOLDERRM/D.
16
1
MC3x025DW
AWLYYWWG
x = 3 or 4
A = Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
G = Pb−Free Package
See detailed ordering and shipping information in the package
dimensions section on page 18 of this data sheet.
ORDERING INFORMATION