Datasheet LT8645S-2 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | 65V, 8A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current |
| Seiten / Seite | 30 / 1 — FEATURES. DESCRIPTION. Silent Switcher® Architecture. Ultralow EMI … |
| Revision | A |
| Dateiformat / Größe | PDF / 3.3 Mb |
| Dokumentensprache | Englisch |
FEATURES. DESCRIPTION. Silent Switcher® Architecture. Ultralow EMI Emissions. Optional Spread Spectrum Modulation
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LT8645S-2 65V, 8A Synchronous Step-Down Silent Switcher with 2.5µA Quiescent Current
FEATURES DESCRIPTION
n
Silent Switcher® Architecture
The LT®8645S-2 synchronous step-down regulator fea- n
Ultralow EMI Emissions
tures Silent Switcher architecture designed to minimize n
Optional Spread Spectrum Modulation
EMI emissions while delivering high efficiency at high n
High Efficiency at High Frequency
switching frequencies. This performance makes the n
Up to 95% Efficiency at 1MHz, 12VIN to 5VOUT
LT8645S-2 ideal for noise sensitive applications and n
Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
environments. n
Wide Input Voltage Range: 3.4V to 65V
The fast, clean, low-overshoot switching edges enable n
Ultralow Quiescent Current Burst Mode Operation
high efficiency operation even at high switching frequen- n
2.5μA IQ Regulating 12VIN to 3.3VOUT
cies, leading to a small overall solution size. Peak current n
Output Ripple < 10mVP-P
mode control with a 40ns minimum on-time allows high n Fast Minimum Switch On-Time: 40ns step-down ratios even at high switching frequencies. n Low Dropout Under All Conditions: 60mV at 1A n Adjustable and Synchronizable: 200kHz to 2.2MHz Burst Mode® operation enables ultralow standby current n Peak Current Mode Operation consumption, pulse-skipping mode al ows ful switch- n Output Soft-Start and Tracking ing frequency at lower output loads, or spread spectrum n Small 32-Lead 6mm × 4mm LQFN Package operation can further reduce EMI emissions. n AEC-Q100 Qualified for Automotive Applications
INTERNAL CAPS VC COMP 150ºC GRADE
LT8645S* Yes Internal No
APPLICATIONS
LT8646S* Yes External No n Automotive and Industrial Supplies LT8645S-2 No Internal Yes n General Purpose Step-Down *See LT8645S/LT8646S Data Sheet n GSM Power Supplies All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345.
TYPICAL APPLICATION 5V 8A Step-Down Converter 12VIN to 5VOUT Efficiency
VIN 5.5V TO 65V 100 4.0 4.7µF V EN/UV 3.5 IN VIN 95 0.47µF 0.47µF 90 EFFICIENCY 3.0 GND GND POWER LOSS (W) LT8645S-2 85 2.5 BST 0.1µF 2.2µH VOUT 80 2.0 SW 5V BIAS 8A 75 1.5 EFFICIENCY (%) POWER LOSS INTVCC 2.2pF 1M 70 1.0 1µF RT FB 100µF 65 1MHz, L = 2.2µH 0.5 41.2k GND 243k 2MHz, L = 1µH 60 0 1 2 3 4 5 6 7 8 f LOAD CURRENT (A) 8645S-2 TA01a SW = 1MHz 8645S-2 TA01b Rev. A Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Applications Related Parts
FEATURES DESCRIPTION
n
Silent Switcher® Architecture
The LT®8645S-2 synchronous step-down regulator fea- n
Ultralow EMI Emissions
tures Silent Switcher architecture designed to minimize n
Optional Spread Spectrum Modulation
EMI emissions while delivering high efficiency at high n
High Efficiency at High Frequency
switching frequencies. This performance makes the n
Up to 95% Efficiency at 1MHz, 12VIN to 5VOUT
LT8645S-2 ideal for noise sensitive applications and n
Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT
environments. n
Wide Input Voltage Range: 3.4V to 65V
The fast, clean, low-overshoot switching edges enable n
Ultralow Quiescent Current Burst Mode Operation
high efficiency operation even at high switching frequen- n
2.5μA IQ Regulating 12VIN to 3.3VOUT
cies, leading to a small overall solution size. Peak current n
Output Ripple < 10mVP-P
mode control with a 40ns minimum on-time allows high n Fast Minimum Switch On-Time: 40ns step-down ratios even at high switching frequencies. n Low Dropout Under All Conditions: 60mV at 1A n Adjustable and Synchronizable: 200kHz to 2.2MHz Burst Mode® operation enables ultralow standby current n Peak Current Mode Operation consumption, pulse-skipping mode al ows ful switch- n Output Soft-Start and Tracking ing frequency at lower output loads, or spread spectrum n Small 32-Lead 6mm × 4mm LQFN Package operation can further reduce EMI emissions. n AEC-Q100 Qualified for Automotive Applications
INTERNAL CAPS VC COMP 150ºC GRADE
LT8645S* Yes Internal No
APPLICATIONS
LT8646S* Yes External No n Automotive and Industrial Supplies LT8645S-2 No Internal Yes n General Purpose Step-Down *See LT8645S/LT8646S Data Sheet n GSM Power Supplies All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345.
TYPICAL APPLICATION 5V 8A Step-Down Converter 12VIN to 5VOUT Efficiency
VIN 5.5V TO 65V 100 4.0 4.7µF V EN/UV 3.5 IN VIN 95 0.47µF 0.47µF 90 EFFICIENCY 3.0 GND GND POWER LOSS (W) LT8645S-2 85 2.5 BST 0.1µF 2.2µH VOUT 80 2.0 SW 5V BIAS 8A 75 1.5 EFFICIENCY (%) POWER LOSS INTVCC 2.2pF 1M 70 1.0 1µF RT FB 100µF 65 1MHz, L = 2.2µH 0.5 41.2k GND 243k 2MHz, L = 1µH 60 0 1 2 3 4 5 6 7 8 f LOAD CURRENT (A) 8645S-2 TA01a SW = 1MHz 8645S-2 TA01b Rev. A Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Applications Related Parts