Datasheet LT3667 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 40V 400mA Step-Down Switching Regulator with Dual Fault Protected LDOs |
| Pages / Page | 34 / 1 — FEATURES. DESCRIPTION. Triple Output Supply from a Single Input Requires. … |
| File Format / Size | PDF / 446 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Triple Output Supply from a Single Input Requires. Only One Inductor
Model Line for this Datasheet
Text Version of Document
LT3667 40V 400mA Step-Down Switching Regulator with Dual Fault Protected LDOs
FEATURES DESCRIPTION
n
Triple Output Supply from a Single Input Requires
The LT®3667 is a monolithic triple power supply composed
Only One Inductor
of a 400mA buck switching regulator and two 200mA low n
IQ = 50μA at 12VIN to 5V, 3.3V and 2.5V with No Load
dropout linear regulators (LDOs). n
Buck Regulator:
The buck regulator includes a high efficiency switch, a
Low Ripple (<15mVP-P) Burst Mode Operation
® boost diode, and the necessary oscillator, control and
400mA Output with Internal Power Switch
logic circuitry. Current mode topology is used for fast
4.3V to 40V Input Operation Range (60V Max)
transient response and good loop stability. Low ripple n
Dual Low Dropout Linear Regulators
Burst Mode operation maintains high efficiency at low
200mA Outputs with Programmable Current Limits
output currents while keeping output ripple below 15mV
1.6V to 45V Input Range
in a typical application.
Fault Protected to ±45V
n Adjustable 250kHz to 2.2MHz Switching Frequency Each LDO supplies 200mA of output current with a typical n Synchronizable Between 300kHz and 2.2MHz dropout voltage of 340mV, and each LDO has an accurate n Programmable Undervoltage Lockout resistor programmable current limit. n Power Good Indicators Internal protection circuitry includes reverse-battery n Available in a Thermally-Enhanced 16-Lead MSOP protection, current limiting, thermal limiting and reverse and 24-Lead (3mm × 5mm) QFN Packages current protection.
APPLICATIONS
The LT3667 is available in a thermally-enhanced 16-Lead MSOP and a 24-Pin 3mm x 5mm QFN package with ex- n Automotive Battery Regulation posed pad for low thermal resistance. n Power for Portable Instrumentation L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n Industrial Supplies of Linear Technology Corporation. All other trademarks are the property of their respective n Fault-Protected Sensor Supply owners.
TYPICAL APPLICATION
VIN 6V TO 40V
No-Load Supply Current
TRANSIENT 4.7µF TO 60V 100 UVLO1 IN1 BOOST 90 0.22µF 22µH SW 5V 80 ON OFF EN 200mA 22µF 70 PG DA 931k FB1 60 RT 174k LT3667 22pF 294k 50 BD 40 IN2 IN3 30 SUPPLY CURRENT (µA) 2.5V 3.3V 100mA OUT2 OUT3 100mA 20 340k 499k 10 4.7µF FB2 FB3 2.2µF 0 158k EN2/ILIM2 GND EN3/ILIM3 158k 5 10 15 20 25 30 35 INPUT VOLTAGE (V) 3667 TA01a 3667 TA01b 3667fb For more information www.linear.com/LT3667 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Order Information Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Triple Output Supply from a Single Input Requires
The LT®3667 is a monolithic triple power supply composed
Only One Inductor
of a 400mA buck switching regulator and two 200mA low n
IQ = 50μA at 12VIN to 5V, 3.3V and 2.5V with No Load
dropout linear regulators (LDOs). n
Buck Regulator:
The buck regulator includes a high efficiency switch, a
Low Ripple (<15mVP-P) Burst Mode Operation
® boost diode, and the necessary oscillator, control and
400mA Output with Internal Power Switch
logic circuitry. Current mode topology is used for fast
4.3V to 40V Input Operation Range (60V Max)
transient response and good loop stability. Low ripple n
Dual Low Dropout Linear Regulators
Burst Mode operation maintains high efficiency at low
200mA Outputs with Programmable Current Limits
output currents while keeping output ripple below 15mV
1.6V to 45V Input Range
in a typical application.
Fault Protected to ±45V
n Adjustable 250kHz to 2.2MHz Switching Frequency Each LDO supplies 200mA of output current with a typical n Synchronizable Between 300kHz and 2.2MHz dropout voltage of 340mV, and each LDO has an accurate n Programmable Undervoltage Lockout resistor programmable current limit. n Power Good Indicators Internal protection circuitry includes reverse-battery n Available in a Thermally-Enhanced 16-Lead MSOP protection, current limiting, thermal limiting and reverse and 24-Lead (3mm × 5mm) QFN Packages current protection.
APPLICATIONS
The LT3667 is available in a thermally-enhanced 16-Lead MSOP and a 24-Pin 3mm x 5mm QFN package with ex- n Automotive Battery Regulation posed pad for low thermal resistance. n Power for Portable Instrumentation L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n Industrial Supplies of Linear Technology Corporation. All other trademarks are the property of their respective n Fault-Protected Sensor Supply owners.
TYPICAL APPLICATION
VIN 6V TO 40V
No-Load Supply Current
TRANSIENT 4.7µF TO 60V 100 UVLO1 IN1 BOOST 90 0.22µF 22µH SW 5V 80 ON OFF EN 200mA 22µF 70 PG DA 931k FB1 60 RT 174k LT3667 22pF 294k 50 BD 40 IN2 IN3 30 SUPPLY CURRENT (µA) 2.5V 3.3V 100mA OUT2 OUT3 100mA 20 340k 499k 10 4.7µF FB2 FB3 2.2µF 0 158k EN2/ILIM2 GND EN3/ILIM3 158k 5 10 15 20 25 30 35 INPUT VOLTAGE (V) 3667 TA01a 3667 TA01b 3667fb For more information www.linear.com/LT3667 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Order Information Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Revision History Typical Application Related Parts
