Datasheet LT8495 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | SEPIC/Boost Converter with 2A, 70V Switch, 9μA Quiescent Current, POR and Watchdog Timer |
| Pages / Page | 34 / 1 — FEATURES. DESCRIPTION. Wide Input Voltage Range of ~1V to 60V. (2.5V to … |
| File Format / Size | PDF / 1.3 Mb |
| Document Language | English |
FEATURES. DESCRIPTION. Wide Input Voltage Range of ~1V to 60V. (2.5V to 32V for Start-Up). Low Ripple Burst Mode® Operation
Model Line for this Datasheet
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LT8495 SEPIC/Boost Converter with 2A, 70V Switch, 9µA Quiescent Current, POR and Watchdog Timer
FEATURES DESCRIPTION
n
Wide Input Voltage Range of ~1V to 60V
The LT®8495 is an adjustable frequency (250kHz to 1.5MHz)
(2.5V to 32V for Start-Up)
monolithic switching regulator with a power-on reset and n
Low Ripple Burst Mode® Operation
watchdog timer. Quiescent current can be less than 9µA n
9µA IQ at 12VIN to 5.0VOUT
when operating and is ~0.3µA when SWEN, WDE and RSTIN n
Output Ripple (<10mV Typ.)
are low. Configurable as a SEPIC, boost or flyback con- n
Dual Supply Pins:
verter, the low ripple Burst Mode operation maintains high n
Improves Efficiency
efficiency at low output current while keeping output n
Reduces Minimum Supply Voltage to ~1V after
ripple below 10mV. Dual supply pins (VIN and BIAS) allow
Start-Up to Extend Battery Life
the part to automatically operate from the most efficient n
Integrated 2A/70V Power Switch
supply. Input supply voltage can be up to 60V for SEPIC n
Programmable Watchdog Timer Can Operate When
topologies and up to 32V (with ride-through up to 60V)
VIN Supply Is Removed
for boost and flyback topologies. After start-up, battery n
Programmable Power-On Reset Timer (POR) with
life is extended since the part can draw current from its
RST Functional for Input Supply Down to 1.3V
output (BIAS) even when VIN voltage drops below 2.5V. n
FMEA Fault Tolerant in TSSOP Package
The reset and watchdog timeout periods are independently n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK adjustable using external capacitors. Using a resistor divider Topologies on the SWEN pin provides a programmable undervoltage n Programmable Switching Frequency: lockout (UVLO) for the converter. A resistor divider connected 250kHz to 1.5MHz to RSTIN provides UVLO control that asserts the RST pin. n UVLO Programmable on SWEN and RSTIN Pins n Soft-Start Programmable with One Capacitor Additional features such as frequency foldback and soft- n Small 20-Lead QFN or 20-Lead TSSOP Packages start are integrated. Fault tolerance in the TSSOP allows for adjacent pin shorts or an open without raising the
APPLICATIONS
output voltage above its programmed value. The LT8495 n is available in 20-lead QFN and 20-lead TSSOP packages Automotive ECU Power n with exposed pads for low thermal resistance. Power for Portable Products n Industrial Supplies L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION No-Load Supply Current Efficiency 450kHz, 5V Output SEPIC Converter
25 90 2.2µF 15µH V V IN • OUT 3V TO 60V 5V 85 20 VIN = 24V 47µF 0.35A (VIN = 3V) 2.2µF 15µH 1M 4.7pF ×2 0.6A (VIN = 5V) 1.0A (V 80 IN >12V) V • 15 IN = 12V 75 VIN = 5V SW BIAS 8.87k V Y CURRENT (µA) 10 IN RSTIN SWEN FB EFFICIENCY (%) WATCHDOG ENABLED 70 LT8495 316k SUPPL CWDT 5 1nF GND CPOR WATCHDOG DISABLED 65 4.7nF SS WDO 1µF RT WDE 0 60 169k RST µC 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 WDI INPUT VOLTAGE (V) LOAD CURRENT (A) 8495 TA01a 8495 TA01b 8495 TA01c 8495fb For more information www.linear.com/LT8495 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Operation Applications Information Typical Applications Package Description Revision History Typical Applications Related Parts
FEATURES DESCRIPTION
n
Wide Input Voltage Range of ~1V to 60V
The LT®8495 is an adjustable frequency (250kHz to 1.5MHz)
(2.5V to 32V for Start-Up)
monolithic switching regulator with a power-on reset and n
Low Ripple Burst Mode® Operation
watchdog timer. Quiescent current can be less than 9µA n
9µA IQ at 12VIN to 5.0VOUT
when operating and is ~0.3µA when SWEN, WDE and RSTIN n
Output Ripple (<10mV Typ.)
are low. Configurable as a SEPIC, boost or flyback con- n
Dual Supply Pins:
verter, the low ripple Burst Mode operation maintains high n
Improves Efficiency
efficiency at low output current while keeping output n
Reduces Minimum Supply Voltage to ~1V after
ripple below 10mV. Dual supply pins (VIN and BIAS) allow
Start-Up to Extend Battery Life
the part to automatically operate from the most efficient n
Integrated 2A/70V Power Switch
supply. Input supply voltage can be up to 60V for SEPIC n
Programmable Watchdog Timer Can Operate When
topologies and up to 32V (with ride-through up to 60V)
VIN Supply Is Removed
for boost and flyback topologies. After start-up, battery n
Programmable Power-On Reset Timer (POR) with
life is extended since the part can draw current from its
RST Functional for Input Supply Down to 1.3V
output (BIAS) even when VIN voltage drops below 2.5V. n
FMEA Fault Tolerant in TSSOP Package
The reset and watchdog timeout periods are independently n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK adjustable using external capacitors. Using a resistor divider Topologies on the SWEN pin provides a programmable undervoltage n Programmable Switching Frequency: lockout (UVLO) for the converter. A resistor divider connected 250kHz to 1.5MHz to RSTIN provides UVLO control that asserts the RST pin. n UVLO Programmable on SWEN and RSTIN Pins n Soft-Start Programmable with One Capacitor Additional features such as frequency foldback and soft- n Small 20-Lead QFN or 20-Lead TSSOP Packages start are integrated. Fault tolerance in the TSSOP allows for adjacent pin shorts or an open without raising the
APPLICATIONS
output voltage above its programmed value. The LT8495 n is available in 20-lead QFN and 20-lead TSSOP packages Automotive ECU Power n with exposed pads for low thermal resistance. Power for Portable Products n Industrial Supplies L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION No-Load Supply Current Efficiency 450kHz, 5V Output SEPIC Converter
25 90 2.2µF 15µH V V IN • OUT 3V TO 60V 5V 85 20 VIN = 24V 47µF 0.35A (VIN = 3V) 2.2µF 15µH 1M 4.7pF ×2 0.6A (VIN = 5V) 1.0A (V 80 IN >12V) V • 15 IN = 12V 75 VIN = 5V SW BIAS 8.87k V Y CURRENT (µA) 10 IN RSTIN SWEN FB EFFICIENCY (%) WATCHDOG ENABLED 70 LT8495 316k SUPPL CWDT 5 1nF GND CPOR WATCHDOG DISABLED 65 4.7nF SS WDO 1µF RT WDE 0 60 169k RST µC 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 WDI INPUT VOLTAGE (V) LOAD CURRENT (A) 8495 TA01a 8495 TA01b 8495 TA01c 8495fb For more information www.linear.com/LT8495 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Operation Applications Information Typical Applications Package Description Revision History Typical Applications Related Parts
