
Bay Linear, Inc
2418 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556 www.baylinear.com
BiCMOS Current Mode PWM Controller
B38C42/43/44/45
Advance Information
Pin Connection
Ordering Information
Devices
B38C42M
B38C42P
B38C43M
B38C43P
B38C44M
B38C44P
B38C45M
B38C45P
Package
SO-8
8-DIP
SO-8
8-DIP
SO-8
8-DIP
SO-8
8-DIP
Temp.
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
-40
°
C to +85
°
C
Description
The Bay Linear B38C42/43/44/45 are fixed frequency and
high performance current-mode PWM controller in BiCMOS.
They are pin compatible with all bipolar 384X’s controllers are
similar to the MIC38C4X family. These devices are designed
for DC-to-DC converter applications and feature a trimmed
oscillator discharge current and bandgap reference.
The benefit of the BiCMOS process provides significant
performance improvement compared to Bipolar 384X devices.
At 15V
IN
the start-up current is reduced to 50
μ
A (typ.) from
0.17 mA with an operating current reduced to 4mA (typ.) from
14mA. Also, quicker output rise and fall times drive larger
MOSFET ‘s and rail-to-rail output capability improves
efficiency, especially lower supply voltages.
Major differences between members of these series are the
UVLO thresholds. Typical UVLO thresholds of 14.5V (on)
and 9V (off) for the B38C42 and B38C44 devices make them
ideally suited to off-line applications. The corresponding
typical thresholds for the B38C43 and B3845 devcies are 8.4V
(on) and 7.6V (off).
The B39C4X devices are available in 8 pin DIP and SOIC.
Features
Low-Power BiCMOS Process
Ultra Low Start-Up Current of 50
μ
A (typ.)
Very Lower Operating Current (4mA)
Current Mode Operation
≥
500KHz
CMOS outputs with Rail to Rail outputs
Under Voltage Lockout with Hysteresis
5V Trimmed Bandgap Reference
Trimmed Oscillator Discharged Current
Low Cross-Conduction Currents
Available in 8 pin SOIC and 8PDip
Similar to MIC38C42/43/44/45
Pin to Pin compatible with UC3842X Family
Applications
Switched and Current Mode Power Supplies
Off-line Power Supply
Step-Up (Buck), Step-Down (Boost) Regulator
Flyback, Isolated Regulators
Synchronous FET converters
Forward Converters
8-SOIC and 8-PDip
Top
GND
VDD
OUTPUT
REF
2
1
3
4
8
7
6
5
COMP
ISENSE
RT/CT
FB
Bay Linear
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