Datasheet LT3690 (Analog Devices)
| Hersteller | Analog Devices |
| Beschreibung | 36V, 4A, 1.5MHz Synchronous Step-Down Switching Regulator with 70μA Quiescent Current |
| Seiten / Seite | 30 / 1 — FeaTures. DescripTion. Wide Input Range:. – Operation from 3.9V to 36V. – … |
| Dateiformat / Größe | PDF / 1.2 Mb |
| Dokumentensprache | Englisch |
FeaTures. DescripTion. Wide Input Range:. – Operation from 3.9V to 36V. – Overvoltage Lockout Protects Circuits
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LT3690 36V, 4A, 1.5MHz Synchronous Step-Down Switching Regulator with 70µA Quiescent Current
FeaTures DescripTion
n
Wide Input Range:
The LT®3690 is an adjustable frequency monolithic buck
– Operation from 3.9V to 36V
switching regulator that accepts input voltages up to 36V.
– Overvoltage Lockout Protects Circuits
A high efficiency 90mΩ switch is included on the device
Through 60V Transients
along with the boost diode and the necessary oscillator, n
4A Maximum Output Current
control, and logic circuitry. The internal synchronous power n
Integrated 30mΩ N-Channel Synchronous Switch
switch of 30mΩ increases efficiency and eliminates the n
Low Ripple (<15mVP-P) Burst Mode
®
Operation:
need for an external Schottky catch diode. Current mode
IQ = 70µA at 12VIN to 3.3VOUT
topology is used for fast transient response and good n
Programmable Input Undervoltage Lockout
loop stability. Shutdown reduces input supply current to n 0.8V Feedback Reference Voltage less than 1µA. The low ripple Burst Mode maintains high n Output Voltage: 0.8V to 20V efficiency at low output currents while keeping output n Programmable and Synchronizable Oscillator ripple below 15mV in typical applications. (170kHz to 1.5MHz) The LT3690 features robust operation and is easily con- n Soft-Startup and Output Voltage Tracking figurable. Using a resistor divider on the UVLO pin provides n Short-Circuit Robust a programmable undervoltage lockout. A power good flag n Power Good Flag signals when VOUT reaches 90% of the programmed out- n Small Thermally Enhanced 4mm × 6mm QFN Package put voltage. Protection circuitry senses the current in the power switches to protect the LT3690 against short-circuit
applicaTions
conditions. Frequency foldback and thermal shutdown n Automotive Systems provide additional protection. The LT3690 is available in n Industrial Supplies a 4mm × 6mm QFN package with exposed pads for low n Distributed Supply Regulation thermal resistance. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion 3.3V Step-Down Converter Efficiency and Power Loss
VIN 100 2.5 4.5V TO 36V 0.68µF V 10µF EN V OUT = 5V IN BST 3.3µH 3.3V 90 2.0 UVLO SW V 4A OUT = 3.3V POWER LOSS (W) LT3690 SS BIAS 80 1.5 V V OUT = 5V C PG 316k 70 1.0 EFFICIENCY (%) V 22k VCCINT FB OUT = 3.3V 0.47µF SYNC RT 60 0.5 VIN = 12V GND 100µF L = 4.7µH 680pF 32.4k 102k ƒ = 600kHz ƒ = 600kHz 50 0 0 0.5 1 1.5 2 2.5 3 3.5 4 3690 TA01a LOAD CURRENT (A) 3690 TA01b 3690fb For more information www.linear.com/LT3690 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information 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
Wide Input Range:
The LT®3690 is an adjustable frequency monolithic buck
– Operation from 3.9V to 36V
switching regulator that accepts input voltages up to 36V.
– Overvoltage Lockout Protects Circuits
A high efficiency 90mΩ switch is included on the device
Through 60V Transients
along with the boost diode and the necessary oscillator, n
4A Maximum Output Current
control, and logic circuitry. The internal synchronous power n
Integrated 30mΩ N-Channel Synchronous Switch
switch of 30mΩ increases efficiency and eliminates the n
Low Ripple (<15mVP-P) Burst Mode
®
Operation:
need for an external Schottky catch diode. Current mode
IQ = 70µA at 12VIN to 3.3VOUT
topology is used for fast transient response and good n
Programmable Input Undervoltage Lockout
loop stability. Shutdown reduces input supply current to n 0.8V Feedback Reference Voltage less than 1µA. The low ripple Burst Mode maintains high n Output Voltage: 0.8V to 20V efficiency at low output currents while keeping output n Programmable and Synchronizable Oscillator ripple below 15mV in typical applications. (170kHz to 1.5MHz) The LT3690 features robust operation and is easily con- n Soft-Startup and Output Voltage Tracking figurable. Using a resistor divider on the UVLO pin provides n Short-Circuit Robust a programmable undervoltage lockout. A power good flag n Power Good Flag signals when VOUT reaches 90% of the programmed out- n Small Thermally Enhanced 4mm × 6mm QFN Package put voltage. Protection circuitry senses the current in the power switches to protect the LT3690 against short-circuit
applicaTions
conditions. Frequency foldback and thermal shutdown n Automotive Systems provide additional protection. The LT3690 is available in n Industrial Supplies a 4mm × 6mm QFN package with exposed pads for low n Distributed Supply Regulation thermal resistance. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion 3.3V Step-Down Converter Efficiency and Power Loss
VIN 100 2.5 4.5V TO 36V 0.68µF V 10µF EN V OUT = 5V IN BST 3.3µH 3.3V 90 2.0 UVLO SW V 4A OUT = 3.3V POWER LOSS (W) LT3690 SS BIAS 80 1.5 V V OUT = 5V C PG 316k 70 1.0 EFFICIENCY (%) V 22k VCCINT FB OUT = 3.3V 0.47µF SYNC RT 60 0.5 VIN = 12V GND 100µF L = 4.7µH 680pF 32.4k 102k ƒ = 600kHz ƒ = 600kHz 50 0 0 0.5 1 1.5 2 2.5 3 3.5 4 3690 TA01a LOAD CURRENT (A) 3690 TA01b 3690fb For more information www.linear.com/LT3690 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts