UC3845ADM Microsemi Analog Mixed Signal Group, UC3845ADM Datasheet

IC CTRLR PWM CURRENT MODE 8SOIC

UC3845ADM

Manufacturer Part Number
UC3845ADM
Description
IC CTRLR PWM CURRENT MODE 8SOIC
Manufacturer
Microsemi Analog Mixed Signal Group
Datasheet

Specifications of UC3845ADM

Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
500kHz
Duty Cycle
50%
Voltage - Supply
8.2 V ~ 25 V
Buck
Yes
Boost
Yes
Flyback
Yes
Inverting
No
Doubler
No
Divider
No
Cuk
No
Isolated
Yes
Operating Temperature
0°C ~ 70°C
Package / Case
8-SOIC
Frequency-max
500kHz
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
UC3845ADM-TR
Manufacturer:
VIA
Quantity:
30
T
Copyright © 1995
Rev. 1.2a,2005-03-09
H E
all the necessary features to implement off-line
fixed-frequency, current-mode switching power
supplies
components. The current mode architecture
demonstrates improved load regulation, pulse-
by-pulse current limiting and inherent protection
of the power supply output switch. The IC
includes: A bandgap reference trimmed to ±1%
accuracy, an error amplifier, a current sense
comparator with internal clamp to 1V, a high
current totem pole output stage for fast
switching
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
The UC184xA family of control ICs provides
I
N F I N I T E
C
OMPARISON OF
with
of
-40 to +85
-55 to 125
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. UC3842ADM-TR)
T
0 to 70
power
SG384x
Min. Li m it
A
a
(°C)
P
minimum
O W E R
MOSFET's,
Discharge Cu rrent Dist ribution - mA
7.5
RoHS Compliant / Pb-free
11861 W
M
UC384
Transition DC: 0503
P R O D U C T H I G H L I G H T
T
A
UC384xAM
UC284xAM
-3 s
=25 C
O F
7.8
Plastic DIP
8-Pin
ESTERN
of
D E S C R I P T I O N
L
X
-
UC384xA
I
and
I N
A
external
N N O V A T I O N
A
Mean
VS
F
8.3
VENUE
I N I T Y
an
. SG384
, G
externally programmable oscillator to set
frequency and maximum duty cycle. The
undervoltage lock-out is designed to operate with
250µA typ. start-up current, allowing an efficient
bootstrap supply voltage design. Available
options for this family of products, such as start-
up voltage hysteresis and duty cycle, are
summarized below in the Available Options
section. The UC184xA family of control ICs is
also available in 14-pin SOIC package which
makes the Power Output Stage Collector and
Ground pins available.
ARDEN
+3s
8.8
DM
PACKAGE ORDER INFO
RoHS Compliant / Pb-free Transition DC: 0440
M
X
UC384xADM
UC284xADm
I C R O E L E C T R O N I C S
G
D
ROVE
9.3
ISCHARGE
Plastic SOIC
8-Pin
, CA. 92841, 714-898-8121, F
SG384x
Max. Limit
-
C
C
URRENT
U R R E N T
P
D
R O D U C T I O N
UC184xA / 284xA / 384xA
UC384xAD
UC284xAD
Plastic SOIC
14-Pin
M
I
-
N C
AX
O D E
: 714-893-2570
.
P W M C
Available Options
UCx842A
UCx843A
UCx844A
UCx845A
D
Part#
Y
A T A
LOW START-UP CURRENT.
(0.5mA max.)
DISCHARGE CURRENT. (See
Product Highlight)
OPTIMIZED FOR OFF-LINE
AND DC-TO-DC
CONVERTERS.
AUTOMATIC FEED FORWARD
COMPENSATION.
PULSE-BY-PULSE CURRENT
LIMITING.
ENHANCED LOAD RESPONSE
CHARACTERISTICS.
UNDER-VOLTAGE LOCKOUT
WITH HYSTERESIS.
DOUBLE PULSE
SUPPRESSION.
HIGH-CURRENT TOTEM POLE
OUTPUT.
INTERNALLY TRIMMED
BANDGAP REFERENCE.
500KHz OPERATION.
LOW RO ERROR AMPLIFIER.
ECONOMICAL OFF-LINE
FLYBACK OR FORWARD
CONVERTERS.
DC-DC BUCK OR BOOST
CONVERTERS.
LOW COST DC MOTOR
CONTROL.
TRIMMED OSCILLATOR
UC284xAY
UC184xAY
K E Y F E A T U R E S
K E Y F E A T U R E S
Start-Up
Ceramic DIP
8-Pin
Voltage
O N T R O L L E R
8.4V
8.4A
16V
16V
S
H E E T
-
Hysteresis
0.8V
0.8V
6V
6V
Max. Duty
<100%
<100%
Cycle
<50%
<50%
1

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UC3845ADM Summary of contents

Page 1

The UC184xA family of control ICs provides all the necessary features ...

Page 2

UC184xA/284xA/384xA ...

Page 3

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for UC384xA with 0°C T ...

Page 4

UC184xA/284xA/384xA Parameter Under-Voltage Lockout Section Start Threshold Min. Operation Voltage After Turn-On PWM Section Maximum Duty ...

Page 5

FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING RESISTOR 1M 100k C = 4.7nF T 10k 0 ...

Page 6

UC184xA/284xA/384xA FIGURE 3. — CURRENT SENSE SPIKE SUPPRESSION V DC BUS CC 7 UCx84xA 6 5 ...

Page 7

...

Page 8

UC184xA/284xA/384xA ...

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