42V, 5A Silent Switcher® More Power & Spread Spectrum

42V, 5A Silent Switcher
More Power & Spread Spectrum
®
100
3.00
95
VOUT
2.63
90
LT8640
2.25
Efficiency
85
1.88
80
1.50
75
1.13
70
60
0.5
0.75
12VIN to 5VOUT
1MHz
2MHz
65
1
1.5
2 2.5 3 3.5
Load Current (A)
4
4.5
Power Loss (W)
Efficiency (%)
VIN
0.38
5
0
Actual Size
Demo Circuit
Low EMI/EMC Passes CISPR25 Class 5, 95% Efficient at 2MHz
The LT®8640 joins our growing family of ultralow quiescent current high voltage monolithic synchronous buck regulators.
Its inherent ultralow EMI/EMC emissions, coupled with spread spectrum capabilities, allows it to comfortably meet
CISPR25 class 5 radiated emissions requirements for automotive environments. The LT8640 consumes only 2.5µA of
quiescent current while regulating an output of 3.3V from a 12V input source. It also delivers up to 5A of output
current with efficiencies as high as 96%.
Features
• Ultralow EMI/EMC Emissions
• Spread Spectrum Frequency
Modulation
• Input Voltage: 3.4V to 42V
• Ultralow Quiescent Current in
Standby: 2.5µA
• Low Dropout: 100mV at 1A
All Conditions
• Small 3mm x 4mm QFN Package
www.linear.com/product/LT8640
1-800-4-LINEAR
, LT, LTC, LTM, Linear Technology, the Linear logo
and Silent Switcher are registered trademarks of
Linear Technology Corporation. All other trademarks
are the property of their respective owners
Simplified LT8640 EMI/EMC Curve, IOUT = 4A
50
45
40
Amplitude (dBuV/m)
35
30
25
20
15
10
5
CISPR25 Class 5 Pk Limit
LT8640 Fixed Frequency Mode
LT8640 Spread Spectrum Mode
0
-5
0
100
200
300
Frequency (MHz)
400
500
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