MIC38C42BM Micrel Inc, MIC38C42BM Datasheet - Page 8
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MIC38C42BM
Manufacturer Part Number
MIC38C42BM
Description
IC CTRLR PWM CURRENT MODE 8-SOIC
Manufacturer
Micrel Inc
Datasheet
1.MIC38C42YN.pdf
(11 pages)
Specifications of MIC38C42BM
Duty Cycle
96%
Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
500kHz
Voltage - Supply
9 V ~ 20 V
Buck
Yes
Boost
Yes
Flyback
Yes
Inverting
No
Doubler
No
Divider
No
Cuk
No
Isolated
Yes
Operating Temperature
-40°C ~ 85°C
Package / Case
8-SOIC (3.9mm Width)
Frequency-max
500kHz
Number Of Pwm Outputs
1
On/off Pin
No
Adjustable Output
No
Switching Freq
500KHz
Operating Supply Voltage (max)
20V
Output Current
500A
Synchronous Pin
No
Rise Time
40ns
Fall Time
30ns
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
8
Package Type
SOIC
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MIC38C42BM
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
MIC38C42/3/4/5
Synchronous Buck Converter
Refer to figure 2. This MIC38C43 synchronous buck converter
uses an MIC5022 half-bridge driver to alternately drive the
PWM switch MOSFET (driven by GATEH, or high-side output)
and a MOSFET which functions as a synchronous rectifier
(driven by the GATEL, or low-side output).
The low-side MOSFET turns on when the high-side MOS-
FET is off, allowing current to return from ground. Current
flows through the low-side MOSFET in the source to drain
direction.
M9999-091107
Test
Line Regulation
Load Regulation V
Efficiency
Output Ripple
2200
6.8k
pF
Conditions
V
V
V
47k
3.3k
10k
IN
IN
IN
IN
= 26V to 80V, I
= 48V, I
= 48V, I
= 48V, I
10k
300k
4.3k
4.7nF
0.15µF
O
O
O
= 0.2A to 2A
= 2A
= 2A (20MHz BW)
COM P
F B
I S N S
RT/CT
MIC38C43
*Locate near the MIC38C43 supply pins.
O
Figure 2. 100kHz, Synchronous Buck Converter
= 2A
VOUT
V R E F
GND
VDD
0.1µF*
MKS2
0.1µF
470µF
25V
Results
100mV
0.5%
0.6%
90%
+12V
NC
NC
NC
8
1. Custom Coils, Alcester, SD tel: (605) 934-2460
2. Energy Transformation Systems, Inc. tel: (415) 324-4949.
The on-state voltage drop of the low-side MOSFET is lower
than the forward voltage drop of an equivalent Schottky recti-
fier. This lower voltage drop results in higher efficiency.
A sense resistor (5mΩ) is connected to the driver’s high-
side current sense inputs to provide overcurrent protection.
Refer to the MIC5020, MIC5021, and MIC5022 data sheets
for more information.
Symbol
CT1
T1
L1
VDD
FL T
E N
IN
C T
GND
MIC5022
G A T E H
G A T E L
SH+
SH–
SL+
S L–
V B
Custom Coil
4923
4924
4925
0.1µF
SMP60N06-14
5mΩ
1
35µH
ETS
ETS 92420
ETS 92419
ETS 92421
1000µF
Low ESR
2
5V, 8A
September 2007
V
OUT
Micrel, Inc.