Datasheet LT8494 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | SEPIC/Boost DC/DC Converter with 2A, 70V Switch, and 7μA Quiescent Current |
| Pages / Page | 26 / 1 — FEATURES. DESCRIPTION. Low Ripple Burst Mode® Operation:. 7µA IQ at 12VIN … |
| File Format / Size | PDF / 615 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Low Ripple Burst Mode® Operation:. 7µA IQ at 12VIN to 5VOUT. Output Ripple (<10mV Typ.)
Model Line for this Datasheet
Text Version of Document
LT8494 SEPIC/Boost DC/DC Converter with 2A, 70V Switch, and 7µA Quiescent Current
FEATURES DESCRIPTION
n
Low Ripple Burst Mode® Operation:
The LT®8494 is an adjustable frequency (250kHz to n
7µA IQ at 12VIN to 5VOUT
1.5MHz) monolithic switching regulator. Quiescent cur- n
Output Ripple (<10mV Typ.)
rent can be less than 7µA when operating and is ~0.3µA n
Dual Supply Pins:
when SWEN is low. The LT8494 can be configured as n
Improves Efficiency
either a SEPIC, boost or flyback converter. n
Reduces Minimum Supply Voltage to ~1V After
The low ripple Burst Mode operation maintains high n
Start-Up to Extend Battery Life
efficiency at low output current while keeping output rip- n
Wide Input Voltage Range of ~1V to 60V (2.5V to
ple below 10mV. Dual supply pins (VIN and BIAS) allow
32V for Start-Up)
the part to automatically operate from the most efficient n
PG Functional for Input Supply Down to 1.3V
supply. Input supply voltage can be up to 60V for SEPIC n
FMEA Fault Tolerant in TSSOP Package
topologies and up to 32V (with ride-through up to 60V) n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK for boost and flyback topologies. After start-up, battery Topologies life is extended since the part can draw current from its n NPN Power Switch: 2A/70V output (BIAS) even when VIN voltage drops below 2.5V. n Programmable Switching Frequency: 250kHz to 1.5MHz n UVLO Programmable on SWEN Pin Using a resistor divider on the SWEN pin provides a pro- n Soft-Start Programmable with One Capacitor grammable undervoltage lockout (UVLO) for the con- n Small 20-Lead QFN or 20-Lead TSSOP Packages verter. A power good flag signals when VOUT reaches 92% of the programmed output voltage. Additional features such as frequency foldback and soft-
APPLICATIONS
start are integrated. The LT8494 is available in 20-lead n Automotive ECU Power QFN and 20-lead TSSOP packages with exposed pads n Power for Portable Products for low thermal resistance. Fault tolerance in the TSSOP n Industrial Supplies allows for adjacent pin shorts or an open without raising L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of the output voltage above its programmed value. Analog Devices, Inc. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION 450kHz, 5V Output SEPIC Converter No-Load Supply Current Efficiency
20 2.2µF 90 15µH VIN • VOUT 3V TO 60V • 5V 85 V 0.35A (V IN = 24V 15µH IN = 3V) 15 0.6A (VIN = 5V) 1.0A (VIN > 12V) 80 VIN = 12V V SW 75 V IN BIAS 10 IN = 5V SWEN Y CURRENT (µA) LT8494 1M 4.7pF EFFICIENCY (%) PG 70 4.7µF SUPPL 47µF 5 RT FB SS GND ×2 65 169k 1µF 316k 8494 TA01a 0 60 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 INPUT VOLTAGE (V) LOAD CURRENT (A) 8494 TA01b 8494 TA01c 8494fa For more information www.linear.com/LT8494 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts
FEATURES DESCRIPTION
n
Low Ripple Burst Mode® Operation:
The LT®8494 is an adjustable frequency (250kHz to n
7µA IQ at 12VIN to 5VOUT
1.5MHz) monolithic switching regulator. Quiescent cur- n
Output Ripple (<10mV Typ.)
rent can be less than 7µA when operating and is ~0.3µA n
Dual Supply Pins:
when SWEN is low. The LT8494 can be configured as n
Improves Efficiency
either a SEPIC, boost or flyback converter. n
Reduces Minimum Supply Voltage to ~1V After
The low ripple Burst Mode operation maintains high n
Start-Up to Extend Battery Life
efficiency at low output current while keeping output rip- n
Wide Input Voltage Range of ~1V to 60V (2.5V to
ple below 10mV. Dual supply pins (VIN and BIAS) allow
32V for Start-Up)
the part to automatically operate from the most efficient n
PG Functional for Input Supply Down to 1.3V
supply. Input supply voltage can be up to 60V for SEPIC n
FMEA Fault Tolerant in TSSOP Package
topologies and up to 32V (with ride-through up to 60V) n Fixed Frequency PWM, SEPIC/BOOST/FLYBACK for boost and flyback topologies. After start-up, battery Topologies life is extended since the part can draw current from its n NPN Power Switch: 2A/70V output (BIAS) even when VIN voltage drops below 2.5V. n Programmable Switching Frequency: 250kHz to 1.5MHz n UVLO Programmable on SWEN Pin Using a resistor divider on the SWEN pin provides a pro- n Soft-Start Programmable with One Capacitor grammable undervoltage lockout (UVLO) for the con- n Small 20-Lead QFN or 20-Lead TSSOP Packages verter. A power good flag signals when VOUT reaches 92% of the programmed output voltage. Additional features such as frequency foldback and soft-
APPLICATIONS
start are integrated. The LT8494 is available in 20-lead n Automotive ECU Power QFN and 20-lead TSSOP packages with exposed pads n Power for Portable Products for low thermal resistance. Fault tolerance in the TSSOP n Industrial Supplies allows for adjacent pin shorts or an open without raising L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of the output voltage above its programmed value. Analog Devices, Inc. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION 450kHz, 5V Output SEPIC Converter No-Load Supply Current Efficiency
20 2.2µF 90 15µH VIN • VOUT 3V TO 60V • 5V 85 V 0.35A (V IN = 24V 15µH IN = 3V) 15 0.6A (VIN = 5V) 1.0A (VIN > 12V) 80 VIN = 12V V SW 75 V IN BIAS 10 IN = 5V SWEN Y CURRENT (µA) LT8494 1M 4.7pF EFFICIENCY (%) PG 70 4.7µF SUPPL 47µF 5 RT FB SS GND ×2 65 169k 1µF 316k 8494 TA01a 0 60 0 12 24 36 48 60 0.0 0.2 0.4 0.6 0.8 1.0 INPUT VOLTAGE (V) LOAD CURRENT (A) 8494 TA01b 8494 TA01c 8494fa For more information www.linear.com/LT8494 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts
