© Semiconductor Components Industries, LLC, 2010
August, 2010 − Rev. 1
1 Publication Order Number:
NCV3843BV/D
NCV3843BV
High Performance
Current Mode Controllers
The NCV3843BV is a high performance fixed frequency current
mode controller. They are specifically designed for Off−Line and
DC−DC converter applications offering the designer a cost−effective
solution with minimal external components. These integrated circuits
feature a trimmed oscillator for precise duty cycle control, a
temperature compensated reference, high gain error amplifier, current
sensing comparator, and a high current totem pole output ideally
suited for driving a power MOSFET.
Also included are protective features consisting of input and
reference undervoltage lockouts each with hysteresis, cycle−by−cycle
current limiting, programmable output deadtime, and a latch for single
pulse metering.
These devices are available in a surface mount (SOIC−8) plastic
package as well as the 14−pin plastic surface mount (SOIC−14). The
SOIC−14 package has separate power and ground pins for the totem
pole output stage.
The NCV3843BV is tailored for lower voltage applications having
UVLO thresholds of 8.5 V (on) and 7.6 V (off).
Features
• Trimmed Oscillator for Precise Frequency Control
• Oscillator Frequency Guaranteed at 250 kHz
• Current Mode Operation to 500 kHz
• Automatic Feed Forward Compensation
• Latching PWM for Cycle−By−Cycle Current Limiting
• Internally Trimmed Reference with Undervoltage Lockout
• High Current Totem Pole Output
• Undervoltage Lockout with Hysteresis
• Low Startup and Operating Current
• These are Pb−Free Devices
Figure 1. Simplified Block Diagram
5.0V
Reference
Latching
PWM
V
CC
Undervoltage
Lockout
Oscillator
Error
Amplifier
7(12)
V
C
7(11)
Output
6(10)
Power
Ground
5(8)
3(5)
Current
Sense
Input
V
ref
8(14)
4(7)
2(3)
1(1)
GND 5(9)
R
T
/C
T
Voltage
Feedback
Input
R
R
+
-
V
ref
Undervoltage
Lockout
Output
Compensation
Pin numbers in parenthesis are for the D suffix SOIC−14 package.
V
CC
14
SOIC−14
D SUFFIX
CASE 751A
1
See detailed ordering and shipping information in the package
dimensions section on page 15 of this data sheet.
ORDERING INFORMATION
See general marking information in the device marking
section on page 15 of this data sheet.
DEVICE MARKING INFORMATION
PIN CONNECTIONS
Compensation
NC
Voltage Feedback
NC
Current Sense
NC
R
T
/C
T
Compensation
Voltage Feedback
Current Sense
R
T
/C
T
V
ref
V
ref
NC
V
CC
V
C
Output
GND
Power Ground
V
CC
Output
GND
(Top View)
8
7
6
5
1
2
3
4
1
2
3
4
14
13
12
11
5
6
7
10
9
8
(Top View)
SOIC−8
D1 SUFFIX
CASE 751
1
8
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