ETC B3843 Current mode pwm controller Datasheet

Bay Linear
Inspire the Linear Power
B3842/43/44/45A&A1
Current Mode PWM Controller
Description
Features
The Bay Linear B3842/43/44/45 are fixed frequency currentmode PWM controller. These devices are designed for OffLine and DC-to-DC converter applications with minimum
external components. The B3842 family Feature a trimmed
oscillator for precise duty cycle control, a temperature
compensated reference, high gain error amplifier, current
sensing comparator, and a high current totempole output.
Ideally suited for driving a power N-Channel MOSFET’s. It is
low when is on off stage. Protection circuitry includes built in
under-voltage lockout and current limiting.
Major differences between members of these series are the
UVLO thresholds and maximum duty-cycle ranges. Typical
UVLO thresholds of 16V (on) and 10V (off) on the B3842 and
B3844 devices make them ideally suited to off-line
applications. These corresponding typical thresholds for the
B3842 and B3845 devcies are 8.4V (on) and 7.6V (off). The
B3842 and B3843 devcies can operate to duty cycles
approaching 100%. A duty-Cycle range of 0 to 50% is
obtained by the B3844 and B3845 by the addition of an
internal toggle flip-flop, which blanks the output off every
other clock cycle. It id available in 8 pin DIP and SOIC
packages.
Pin Connection
•
•
•
•
•
•
Low Start-Up and Operating Current
Maximum Duty Cycle
Operating Frequency Up to 500KHz
Under voltage Lockout with Hysteresis
Available in 8 pin SOIC
Similar to industry Standard UC3842
Applications
•
•
Switching Power Supply
Monitor
Ordering Information
Devices
B384X(Z)M
B384X(Z)P
Z=A ON Semi
Package
Temp.
SO-8
0 °C to 70 °C
8-DIP
0 °C to 70 °C
Z=A1 Fairchild & Samsung
8-Pin Surface Mount
COMP
1
8
REF
NC
2
7
VCC
ISENSE
3
6
OUTPUT
4
5
GND
RT/CT
Top View
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Absolute Maximum Rating
Parameter
Supply Voltage
Output Current
Analog Input (pin 2,3)
Error Amp Output Sink Current
Power Dissipation
Storage Temperature Range
Lead Temperature (Soldering 10 Sec.)
Symbol
Value
Unit
VCC
IO
V(ANA)
30
±1
-0.3 to 6.3
10
1
-65 to 150
260
V
A
V
mA
W
°C
°C
ISINK (E.A)
PD
T
TL
Electrical Characteristics
(VCC = 15V;RT = 10Ω, CT = 3.3nF, TA=0 °C to +70°C, unless otherwise specified)
Parameter
Symbol Conditions
MIN
REFERENCE SECTION
Reference Voltage
Line Regulation
Load Regulation
VREF
REG (line)
REG
(LOAD)
Short Circuit Output
Current
ISC
OSCILLATOR SECTION
Oscillator Frequency
f
Frequency Change with
∆f/∆VCC
Voltage
Oscillator Amplitude
VOSC
ERROR AMPLIFIER SECTION
Input Bias Current
IBIAS
Input Voltage
VI(E>A)
Open Loop Voltage Gain
GVO
Power Supply Rejection
PSRR
Ratio
Output Sink Current
ISINK
Output Source Current
ISOURCE
High Output Voltage
VOH
Low Output Voltage
VOL
OUTPUT SECTION
Low Output Voltage
VOL
High Output Voltage
Rise Time
Fall Time
VOH
tR
tF
TYP
MAX
UNIT
4.90
5.00
5.10
V
12V≤VCC≤25V
-
6
20
mA
1mA≤IREF≤20mA
T= 25 °C
-
6
25
T= 25 °C
-
-100
-180
mA
47
-
52
0.05
57
1
KHz
%
-
1.6
-
VP-P
V1 =2.5V
2V≤VO≤4V
12V≤VCC≤25V
2.42
65
60
-0.1
2.50
90
70
-2
2.58
-
µA
V
dB
dB
V2 =2.7V, V1 =1.1V
V2=2.3, V1=5V
V2=2.3, RL= 15Ω to GND
V2=2.7, RL= 15Ω to pin 8
2
-0.6
5
-
7
-1.0
6
0.8
1.1
mA
mA
V
V
ISINK = 20mA
ISINK = 200mA
Source = 20mA
Source = 200mA
TJ = 25 °C, CL=1nF (note3)
TJ = 25 °C, CL=1nF (note3)
-
0.08
1.4
13.5
13.0
45
35
0.4
2.2
150
150
V
TJ = 25 °C. IREF= 1mA
T= 25 °C
12V≤VCC≤25V
13
12
-
V
ns
ns
Note: Output Switch tests are performed under pulsed conditions to minimize power dissipation
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Electrical Characteristics
(VCC = 15V;RT = 10Ω, CT = 3.3nF, TA=0 °C to +70°C, unless otherwise specified)
Parameter
Symbol Conditions
MIN
CURRENT SENSE SECTION
Gain
GV
(Note 1 & 2)
Maximum input Signal
VI(MAX)
V1 = 5V (Note 1)
Power Supply Rejection
PSRR
12V≤VCC≤25V
Ratio
Input Bias Current
IBIAS
UNDER-VOLTAGE LOCKOUT SECTION
B3842/B3844
Start Threshold
VTH(ST)
B3843/B3845
B3842/B3844
Min-Operating Voltage
VOPR(MIN)
(after Turn On)
B3843/B3845
PWM SECTION
B3842/B3843
Max Duty Cycle
D(MAX)
B3844/B3845
Min Duty Cycle
D (MIN)
TOTAL STANDBY CURRENT
B3842A/43A/44A/45A
Start-Up Current
IST
B3842A1/43A1/44A1/45A1
Operating Supply Current
ICC(OPR)
V3=V2=ON
Zener Voltage
VZ
ICC
TYP
MAX
UNIT
3
1
3.15
1.1
V/V
V
70
-
dB
-3
-10
µA
14.5
7.8
8.5
7.0
16
8.4
10
7.6
17.5
9
11.5
8.2
95
47
-
97
48
-
100
50
0
-
0.17
0.45
14
38
0.3
1
17
-
2.85
0.9
30
V
V
%
%
mA
mA
V
Block Diagram
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Figure 1: Error Amp Configuration
Figure 2: Under-Voltage Lockout
3842
3843
Figure 3: Current Sense Circuit
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Figure 4: Slope Conpensation Techigues
B3842A
B3842A
Figure 5:Latched Shutdown
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B384X
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
Advance Information- These data sheets contain descriptions of products that are in development. The specifications are based on the engineering calculations,
computer simulations and/ or initial prototype evaluation.
Preliminary Information- These data sheets contain minimum and maximum specifications that are based on the initial device characterizations. These limits are
subject to change upon the completion of the full characterization over the specified temperature and supply voltage ranges.
The application circuit examples are only to explain the representative applications of the devices and are not intended to guarantee any circuit
design or permit any industrial property right to other rights to execute. Bay Linear takes no responsibility for any problems related to any
industrial property right resulting from the use of the contents shown in the data book. Typical parameters can and do vary in different
applications. Customer’s technical experts must validate all operating parameters including “ Typical” for each customer application.
LIFE SUPPORT AND NUCLEAR POLICY
Bay Linear products are not authorized for and should not be used within life support systems which are intended for surgical
implants into the body to support or sustain life, in aircraft, space equipment, submarine, or nuclear facility applications without
the specific written consent of Bay Linear President.
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
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