Datasheet LT8640, LT8640-1 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 42V, 5A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current |
| Pages / Page | 30 / 1 — FEATURES. DESCRIPTION. Silent Switcher® Architecture. Ultralow EMI … |
| Revision | D |
| File Format / Size | PDF / 1.8 Mb |
| Document Language | English |
FEATURES. DESCRIPTION. Silent Switcher® Architecture. Ultralow EMI Emissions. Spread Spectrum Frequency Modulation
Model Line for this Datasheet
- LT8640EUDC#PBF LT8640EUDC#TRPBF LT8640EUDC-1#PBF LT8640EUDC-1#TRPBF LT8640EUDCF#PBF LT8640EUDCF#TRPBF LT8640EUDCF-1#PBF LT8640EUDCF-1#TRPBF LT8640HUDC#PBF LT8640HUDC#TRPBF LT8640HUDC-1#PBF LT8640HUDC-1#TRPBF LT8640HUDCF#PBF LT8640HUDCF#TRPBF LT8640IUDC#PBF LT8640IUDC#TRPBF LT8640IUDC-1#PBF LT8640IUDC-1#TRPBF LT8640IUDCF#PBF LT8640IUDCF#TRPBF LT8640IUDCF-1#PBF LT8640IUDCF-1#TRPBF LT8640JUDCF#PBF LT8640JUDCF#TRPBF LT8640JUDCF#WPBF LT8640JUDCF#WTRPBF LT8640JUDCF-1#PBF LT8640JUDCF-1#TRPBF LT8640JUDCF-1#WPBF LT8640JUDCF-1#WTRPBF
Text Version of Document
LT8640/LT8640-1 42V, 5A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current
FEATURES DESCRIPTION
n
Silent Switcher® Architecture
The LT®8640/LT8640-1 step-down regulator features Silent n
Ultralow EMI Emissions
Switcher architecture designed to minimize EMI emissions n
Spread Spectrum Frequency Modulation
while delivering high efficiency at frequencies up to 3MHz. n
High Efficiency at High Frequency
An ultralow 2.5µA quiescent current—with the output in n
Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
full regulation—enables applications requiring highest n
Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
efficiency at very small load currents. n
Wide Input Voltage Range: 3.4V to 42V
The LT8640/LT8640-1 al ows high VIN to low VOUT conversion n
5A Maximum Continuous Output, 7A Peak
at high frequency with a fast minimum top switch on-time of
Transient Output
30ns. The SYNC/MODE pin selects between Burst Mode n
Ultralow Quiescent Current Burst Mode® Operation
operation, spread spectrum mode, synchronization to n
2.5µA IQ Regulating 12VIN to 3.3VOUT
an external clock, and either pulse-skipping (LT8640) or n
Output Ripple < 10mVP-P
forced continuous mode (LT8640-1). n
Fast Minimum Switch On-Time: 30ns
n
Low Dropout Under All Conditions: 100mV at 1A SYNC/ 150°C INTERNAL PACKAGE MODE ≠ 0 V
n
C COMP GRADE CLKOUT CAPS Forced Continuous Mode (LT8640-1 Only)
n Safely Tolerates Inductor Saturation in Overload LT8640 QFN Pulse- Skipping Internal Yes No No n Adjustable and Synchronizable: 200kHz to 3MHz LT8640-1 QFN FCM Internal Yes No No n Peak Current Mode Operation LT8640S LQFN FCM Internal No Yes Yes n Output Soft-Start and Tracking LT8643S LQFN FCM External No Yes Yes n Small 18-Lead 3mm × 4mm QFN and Side Wettable QFN LT8640S-2 LQFN FCM Internal Yes Yes No n AEC-Q100 Qualified for Automotive Applications LT8643S-2 LQFN FCM External Yes Yes No
APPLICATIONS
All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345. n Automotive and Industrial Supplies n General Purpose Step-Down n GSM Power Supplies
TYPICAL APPLICATION 12VIN to 5VOUT Efficiency 5V 5A Step-Down Converter
100 3.00 VIN 5.5V TO 42V 95 2.63 4.7µF EN/UV VIN1 VIN2 90 EFFICIENCY 2.25 1µF 1µF POWER LOSS (W) GND1 GND2 85 1.88 LT8640/ PG LT8640-1 BST 80 1.50 0.1µF 3.3µH VOUT 10nF SYNC/MODE SW 5V 75 1.13 TR/SS BIAS 5A EFFICIENCY (%) POWER LOSS 1µF 4.7pF 1M 70 0.75 1MHz, L = 3.3µH INTVCC FB 47µF 41.2k 65 2MHz, L = 2.2µH 0.38 RT GND 243k 3MHz, L = 1µH 60 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 fSW = 1MHz 8640 TA01a LOAD CURRENT (A) 8640 TA01b Rev. D Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Silent Switcher® Architecture
The LT®8640/LT8640-1 step-down regulator features Silent n
Ultralow EMI Emissions
Switcher architecture designed to minimize EMI emissions n
Spread Spectrum Frequency Modulation
while delivering high efficiency at frequencies up to 3MHz. n
High Efficiency at High Frequency
An ultralow 2.5µA quiescent current—with the output in n
Up to 96% Efficiency at 1MHz, 12VIN to 5VOUT
full regulation—enables applications requiring highest n
Up to 95% Efficiency at 2MHz, 12VIN to 5VOUT
efficiency at very small load currents. n
Wide Input Voltage Range: 3.4V to 42V
The LT8640/LT8640-1 al ows high VIN to low VOUT conversion n
5A Maximum Continuous Output, 7A Peak
at high frequency with a fast minimum top switch on-time of
Transient Output
30ns. The SYNC/MODE pin selects between Burst Mode n
Ultralow Quiescent Current Burst Mode® Operation
operation, spread spectrum mode, synchronization to n
2.5µA IQ Regulating 12VIN to 3.3VOUT
an external clock, and either pulse-skipping (LT8640) or n
Output Ripple < 10mVP-P
forced continuous mode (LT8640-1). n
Fast Minimum Switch On-Time: 30ns
n
Low Dropout Under All Conditions: 100mV at 1A SYNC/ 150°C INTERNAL PACKAGE MODE ≠ 0 V
n
C COMP GRADE CLKOUT CAPS Forced Continuous Mode (LT8640-1 Only)
n Safely Tolerates Inductor Saturation in Overload LT8640 QFN Pulse- Skipping Internal Yes No No n Adjustable and Synchronizable: 200kHz to 3MHz LT8640-1 QFN FCM Internal Yes No No n Peak Current Mode Operation LT8640S LQFN FCM Internal No Yes Yes n Output Soft-Start and Tracking LT8643S LQFN FCM External No Yes Yes n Small 18-Lead 3mm × 4mm QFN and Side Wettable QFN LT8640S-2 LQFN FCM Internal Yes Yes No n AEC-Q100 Qualified for Automotive Applications LT8643S-2 LQFN FCM External Yes Yes No
APPLICATIONS
All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345. n Automotive and Industrial Supplies n General Purpose Step-Down n GSM Power Supplies
TYPICAL APPLICATION 12VIN to 5VOUT Efficiency 5V 5A Step-Down Converter
100 3.00 VIN 5.5V TO 42V 95 2.63 4.7µF EN/UV VIN1 VIN2 90 EFFICIENCY 2.25 1µF 1µF POWER LOSS (W) GND1 GND2 85 1.88 LT8640/ PG LT8640-1 BST 80 1.50 0.1µF 3.3µH VOUT 10nF SYNC/MODE SW 5V 75 1.13 TR/SS BIAS 5A EFFICIENCY (%) POWER LOSS 1µF 4.7pF 1M 70 0.75 1MHz, L = 3.3µH INTVCC FB 47µF 41.2k 65 2MHz, L = 2.2µH 0.38 RT GND 243k 3MHz, L = 1µH 60 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 fSW = 1MHz 8640 TA01a LOAD CURRENT (A) 8640 TA01b Rev. D Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
