UC3845BD1G ON Semiconductor, UC3845BD1G Datasheet

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UC3845BD1G

Manufacturer Part Number
UC3845BD1G
Description
IC CTRLR CURRENT MODE HP 8SOIC
Manufacturer
ON Semiconductor
Datasheet

Specifications of UC3845BD1G

Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
275kHz
Duty Cycle
50%
Voltage - Supply
8.2 V ~ 25 V
Buck
No
Boost
Yes
Flyback
Yes
Inverting
Yes
Doubler
No
Divider
No
Cuk
No
Isolated
Yes
Operating Temperature
0°C ~ 70°C
Package / Case
8-SOIC (3.9mm Width)
Frequency-max
275kHz
Duty Cycle (max)
48 %
Output Voltage
4.9 V to 5.1 V
Output Current
1000 mA
Mounting Style
SMD/SMT
Switching Frequency
500 KHz
Operating Supply Voltage
30 V
Maximum Operating Temperature
+ 70 C
Fall Time
50 ns
Minimum Operating Temperature
0 C
Rise Time
50 ns
Synchronous Pin
No
Topology
Boost, Flyback
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
UC3845BD1GOS

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
UC3845BD1G
Manufacturer:
ON Semiconductor
Quantity:
2 000
Part Number:
UC3845BD1G
Manufacturer:
ONSEM
Quantity:
7 236
UC3844B, UC3845B,
UC2844B, UC2845B
High Performance
Current Mode Controllers
current mode controllers. 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 an oscillator, 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.
undervoltage lockouts each with hysteresis, cycle−by−cycle current
limiting, a latch for single pulse metering, and a flip−flop which blanks
the output off every other oscillator cycle, allowing output deadtimes to
be programmed from 50% to 70%.
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.
ideally suited for off−line converters. The UCX845B is tailored for
lower voltage applications having UVLO thresholds of 8.5 V (on) and
7.6 V (off).
Features
Compensation
© Semiconductor Components Industries, LLC, 2008
September, 2008 − Rev. 9
The UC3844B, UC3845B series are high performance fixed frequency
Also included are protective features consisting of input and reference
These devices are available in an 8−pin dual−in−line and surface
The UCX844B has UVLO thresholds of 16 V (on) and 10 V (off),
Trimmed Oscillator for Precise Frequency Control
Oscillator Frequency Guaranteed at 250 kHz
Current Mode Operation to 500 kHz Output Switching Frequency
Output Deadtime Adjustable from 50% to 70%
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
Pb−Free Packages are Available
Feedback
Voltage
Output/
R
Input
T
V
/C
ref
8(14)
T
4(7)
2(3)
1(1)
Amplifier
Pin numbers in parenthesis are for the D suffix SOIC-14 package.
Error
R
R
Figure 1. Simplified Block Diagram
Oscillator
Undervoltage
GND
Lockout
V
ref
5(9)
Reference
5.0V
Latching
PWM
Undervoltage
V
CC
Lockout
V
CC
7(12)
7(11)
6(10)
5(8)
3(5)
1
Output
Power
Ground
Current
Sense Input
V
C
See detailed ordering and shipping information in the package
dimensions section on page 15 of this data sheet.
See general marking information in the device marking
section on page 16 of this data sheet.
DEVICE MARKING INFORMATION
Voltage Feedback
Voltage Feedback
8
14
Compensation
Current Sense
Compensation
Current Sense
8
ORDERING INFORMATION
1
1
http://onsemi.com
1
PIN CONNECTIONS
R
R
T
T
/C
NC
NC
NC
/C
T
T
1
2
3
4
1
2
3
4
5
6
7
(Top View)
(Top View)
Publication Order Number:
CASE 751A
D1 SUFFIX
CASE 626
CASE 751
N SUFFIX
D SUFFIX
SOIC−14
14
13
12
11
10
SOIC−8
PDIP−8
8
7
6
5
9
8
V
V
Output
GN
D
V
NC
V
V
Output
GND
Power Ground
ref
ref
CC
C
CC
UC3844B/D

Related parts for UC3845BD1G

UC3845BD1G Summary of contents

Page 1

UC3844B, UC3845B, UC2844B, UC2845B High Performance Current Mode Controllers The UC3844B, UC3845B series are high performance fixed frequency current mode controllers. They are specifically designed for Off−Line and dc−dc converter applications offering the designer a cost−effective solution with minimal external ...

Page 2

MAXIMUM RATINGS Bias and Driver Voltages (Zero Series Impedance, see also Total Device spec) (Note 1) Total Power Supply and Zener Current Output Current, Source or Sink (Note 2) Output Energy (Capacitive Load per Cycle) Current Sense and Voltage Feedback ...

Page 3

ELECTRICAL CHARACTERISTICS T is the operating ambient temperature range that applies [Note 8], unless otherwise noted.) A Characteristic OSCILLATOR SECTION Discharge Current (V = 2.0 V) OSC T = 25° (UC284XB, UC384XB) A low ...

Page 4

ELECTRICAL CHARACTERISTICS values T is the operating ambient temperature range that applies [Note 12], unless otherwise noted.) A Characteristic PWM SECTION Duty Cycle Maximum (UC284XB, UC384XB) Maximum (UC384XBV) Minimum TOTAL DEVICE Power Supply Current Startup (V = 6.5 V for ...

Page 5

Gain 100 1 100 k f, FREQUENCY (Hz) Figure 6. Error Amp Open Loop Gain and Phase versus Frequency 0 - 4 ...

Page 6

Source Saturation Ä Ä Ä Ä Ä Ä Ä Ä Ä Ä (Load to Ground) -1 25°C A Ä Ä Ä Ä Ä Ä Ä Ä - 2.0 Ä Ä Ä Ä ...

Page 7

The UC3844B, UC3845B series are high performance, fixed frequency, current mode controllers. They are specifically designed for Off−Line and DC−DC converter applications offering the designer a cost−effective solution with minimal external components. A representative block diagram is shown in Figure ...

Page 8

V ref 8(14) R Internal 2. Oscillator 4( 1.0mA Voltage Feedback Input 2(3) Error Amplifier Output/ Compensation 1(1) Pin numbers adjacent to terminals are for the 8-pin dual-in-line package. Pin numbers in parenthesis are ...

Page 9

Undervoltage Lockout Two undervoltage lockout comparators have been incorporated to guarantee that the IC is fully functional before the output stage is enabled. The positive power supply terminal (V ) and the reference output (V CC each monitored by separate ...

Page 10

Ref 8(14) R Bias Osc 4( Clamp 1 2(3) R Comp/Latch 1.0V 1( 5(9) 1. ≈ ...

Page 11

Ref + - + - Comp/Latch Figure 24. Current Waveform Spike Suppression V CC 7(12) 5.0V Ref + - + 7(11 6(10 5(8) Comp/Latch 3(5) Series gate resistor ...

Page 12

Ref + - Comp/Latch MCR 101 The MCR101 SCR must be selected for a holding of < 0 simple two transistor circuit can be used in place of the SCR as shown. ...

Page 13

MDA 202 115 Vac 0.01 8(14) R Bias 33k R Osc 4(7) 1.0nF + 18k 2(3) 100 EA 150k pF 4.7k 1( Primary: 45 Turns #26 AWG Secondary ± Turns #30 AWG (2 Strands) Bifiliar ...

Page 14

UC3845B 8(14) R 2.5V Internal 10k Bias R 3.6V Osc 4(7) 1.0nF + 0.5mA 2R 2(3) R Error Amplifier 1(1) 5(9) The capacitor's equivalent series resistance must limit the Drive Output current to 1 additional series resistor may ...

Page 15

ORDERING INFORMATION Device Operating Temperature Range UC384xBD UC384xBDG UC384xBDR2 UC384xBDR2G UC384xBD1 UC384xBD1G UC384xBD1R2 UC384xBD1R2G UC384xBN UC384xBNG UC284xBD UC284xBDG UC284xBDR2 UC284xBDR2G UC284xBD1 UC284xBD1G UC284xBD1R2 UC284xBD1R2G UC284xBN UC284xBNG UC384xBVD UC384xBVDG UC384xBVDR2 UC384xBVDR2G UC384xBVD1 T UC384xBVD1G UC384xBVD1R2 UC384xBVD1R2G UC384xBVN UC384xBVNG †For information on ...

Page 16

MARKING DIAGRAMS PDIP−8 N SUFFIX CASE 626 8 8 UC384xBN UC384xBVN AWL YYWWG YYWWG 1 1 SOIC−14 D SUFFIX CASE 751A 14 14 UC384xBDG UC384xBVDG AWLYWW AWLYWW 1 1 SOIC−8 D1 SUFFIX CASE 751 8 8 384xB 384xB ALYW ALYWV ...

Page 17

F −A− NOTE 2 C −T− N SEATING PLANE 0.13 (0.005) M PACKAGE DIMENSIONS PDIP−8 N SUFFIX CASE 626−05 ISSUE http://onsemi.com 17 ...

Page 18

G −T− SEATING 14 PL PLANE 0.25 (0.010 14X 0.58 SOIC−14 CASE 751A−03 ISSUE 0.25 (0.010 ...

Page 19

... *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. SENSEFET is a trademark of Semiconductor Components Industries, LLC. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein ...

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