MIC38C42/3/4/5
Micrel
MIC38C42/3/4/5
BiCMOS Current-Mode PWM Controllers
General Description
The MIC38C4x are fixed frequency, high performance, cur-
rent-mode PWM controllers. Micrel鈥檚 BiCMOS devices are
pin compatible with 384x bipolar devices but feature several
improvements.
Undervoltage lockout circuitry allows the 鈥?2 and 鈥?4 versions
to start up at 14.5V and operate down to 9V, and the 鈥?3 and
鈥?5 versions start at 8.4V with operation down to 7.6V. All
versions operate up to 20V.
When compared to bipolar 384x devices operating from a
15V supply, start-up current has been reduced to 50碌A(chǔ)
typical and operating current has been reduced to 4.0 mA
typical. Decreased output rise and fall times drive larger
MOSFETs, and rail-to-rail output capability increases effi-
ciency, especially at lower supply voltages. The MIC38C4x
also features a trimmed oscillator discharge current and
bandgap reference.
MIC38C4x denotes 8-pin plastic DIP, SOIC, and MM8鈩?/div>
packages. MIC38C4x-1 denotes 14-pin plastic DIP and
SOIC packages. 8-pin devices feature small size, while 14-
pin devices separate the analog and power connections for
improved performance and power dissipation.
Features
鈥?Fast 40ns output rise and 30ns output fall times
鈥?鈥?0擄C to +85擄C temperature range
meets UC284x specifications
鈥?High-performance, low-power BiCMOS Process
鈥?Ultralow start-up current (50碌A(chǔ) typical)
鈥?Low operating current (4mA typical)
鈥?CMOS outputs with rail-to-rail swing
鈥?/div>
鈮?/div>
500kHz current-mode operation
鈥?Trimmed 5V bandgap reference
鈥?Pin-for-pin compatible with UC3842/3843/3844/3845(A)
鈥?Trimmed oscillator discharge current
鈥?UVLO with hysteresis
鈥?Low cross-conduction currents
Applications
鈥?/div>
鈥?/div>
鈥?/div>
鈥?/div>
鈥?/div>
鈥?/div>
鈥?/div>
Current-mode, off-line, switched-mode power supplies
Current-mode, dc-to-dc converters.
Step-down 鈥渂uck鈥?regulators
Step-up 鈥渂oost鈥?regulators
Flyback, isolated regulators
Forward converters
Synchronous FET converters
For fast rise and fall times and higher output drive, refer to the
MIC38HC4x.
Functional Diagram
VDD
7 (12)
*
35V
5V
Reference
UVLO
鈥?/div>
VREF
8 (14)
(VD)
(11)
RT/CT
4 (7)
Oscillator
T
Q
鈥?/div>
OUT
6 (10)
FB
2 (3)
2R
2.5V
R
S
R
Q
(PGND)
(8)
*
COMP
1 (1)
GND*(AGND)
5
(9)
ISNS
3 (5)
( ) pins are on MIC38C4x-1 (14-lead) versions only
* MIC38C4x (8-lead) versions only
鈥?/div>
MIC38C42, MIC38C43 (96% max. duty cycle) versions only
鈥?/div>
MIC38C44, MIC38C45 (50% max. duty cycle) versions only
MM8 is a trademark of Micrel, Inc.
Micrel, Inc. 鈥?1849 Fortune Drive 鈥?San Jose, CA 95131 鈥?USA 鈥?tel + 1 (408) 944-0800 鈥?fax + 1 (408) 944-0970 鈥?http://www.micrel.com
August 2000
1
MIC38C42/3/4/5
MIC38C42 PDF文件相關(guān)型號
MIC38C42BN,MIC38C43BN,MIC38C44-1BM
MIC38C42相關(guān)型號PDF文件下載
-
型號
版本
描述
廠商
下載
-
英文版
Micrel Semiconductor [Three-Zone Thermal Supervisor Advance...
-
英文版
SFP Management IC
-
英文版
SFP Management IC
MICREL [Mi...
-
英文版
Micrel Semiconductor [SFP Management IC with Internal Calib...
-
英文版
Micrel Semiconductor [FOM Management IC with Internal Calib...
-
英文版
Micrel Semiconductor [1.2MHz PWM White LED Driver with Inte...
-
英文版
Micrel Semiconductor [8MHz Power System Module with LDO Sta...
-
英文版
750mA UCap Low-Voltage Low-Dropout Regulator
-
英文版
750mA UCap Low-Voltage Low-Dropout Regulator
MICREL [Mi...
-
英文版
Micrel Semiconductor [Push-Pull PWM Controller]
-
英文版
Micrel Semiconductor [Current-Fed PWM Controllers]
-
英文版
Micrel Semiconductor [Flexible Push-Pull PWM Controller]
-
英文版
Flexible Push-Pull PWM Controller
-
英文版
750mA µCap Low-Voltage Low-Dropout Regulator
-
英文版
Micrel Semiconductor [4MHz Internal Inductor PWM Buck Regul...
-
英文版
1A LOW VOLTAGE U CAP LDO REGULATOR
-
英文版
Micrel Semiconductor [1.5A, LOW VOLTAGE UCAP LDO REGULATOR]
-
英文版
Micrel Semiconductor [1.5 A LOW VOLTAGE UCAP LDO REGULATOR]
-
英文版
1.5 A LOW VOLTAGE UCAP LDO REGULATOR
-
英文版
1.5 A LOW VOLTAGE UCAP LDO REGULATOR
MICREL
1
2
3
4
5
6
7
8
9
10
11
12
