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 I = 50A at 12V to 5V, 3.3V and 2.5V with No Load dropout linear regulators (LDOs). Q IN n Buck Regulator: The buck regulator includes a high efficiency switch, a Low Ripple (<15mV ) Burst Mode Operation P-P 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 Each LDO supplies 200mA of output current with a typical Adjustable 250kHz to 2.2MHz Switching Frequency n dropout voltage of 340mV, and each LDO has an accurate Synchronizable Between 300kHz and 2.2MHz n resistor programmable current limit. Programmable Undervoltage Lockout 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 owners. n Fault-Protected Sensor Supply TYPICAL APPLICATION V IN 6V TO 40V No-Load Supply Current TRANSIENT 4.7F 100 TO 60V UVLO1 IN1 BOOST 90 0.22F 22H 5V 80 SW 200mA ON OFF EN 22F 70 931k PG DA 60 FB1 RT 294k 50 LT3667 174k 22pF BD 40 IN2 30 IN3 2.5V 3.3V OUT2 OUT3 20 100mA 100mA 340k 499k 10 4.7F 2.2F FB2 FB3 0 158k 158k 5 10 15 20 25 30 35 EN2/ILIM2 EN3/ILIM3 GND INPUT VOLTAGE (V) 3667 TA01a 3667 TA01b 3667fb 1 For more information www.linear.com/LT3667 SUPPLY CURRENT (A)LT3667 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) FB2, FB3 Voltage .....................................................45V RT Voltage ..................................................................2V OUT2, OUT3 Voltage ...............................................45V FB1 Voltage .................................................................6V IN2, IN3 (QFN) Voltage ............................................45V EN2/ILIM2, EN3/ILIM3 Voltage ...................................4V OUT2 IN2 Differential Voltage ..............................45V PG Voltage ................................................................30V OUT3 IN3/BD Differential Voltage (MSOP)...........45V PG1, PG2, PG3 Voltage (QFN) ...................................30V OUT3 IN3 Differential Voltage (QFN) ....................45V SYNC Voltage (QFN) ...................................................6V IN1, EN, UVLO1 (QFN) Voltage (Note 3) ....................60V Operating Junction Temperature Range (Notes 4, 5) IN1 Reverse Voltage ...............................................0.3V E-, I-Grades ....................................... 40C to 125C EN Pin Current .......................................................1mA H-Grades ........................................... 40C to 150C IN3/BD (MSOP) Voltage ............................................30V Storage Temperature Range .................. 65C to 150C BD (QFN) Voltage ......................................................30V Lead Temperature (Soldering, 10 sec) BOOST Pin Voltage ...................................................50V MSOP Package Only .........................................300C BOOST Pin Above SW Pin .........................................30V PIN CONFIGURATION TOP VIEW 24 23 22 21 BOOST 1 20 IN1 TOP VIEW SYNC 2 19 UVLO1 SW 1 16 DA 2 BOOST 15 IN1 EN 3 PG 18 EN 3 14 PG RT 4 EN3/ILIM3 17 4 17 RT 13 EN3/ILIM3 25 IN3/BD 5 GND 12 EN2/ILIM2 GND 5 BD 16 EN2/ILIM2 6 OUT3 11 IN2 FB3 7 10 OUT2 IN3 6 15 IN2 8 FB1 9 FB2 OUT3 7 14 OUT2 MSE PACKAGE FB3 8 FB2 13 16-LEAD PLASTIC MSOP 9 10 11 12 = 40C/W JA EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB UDD PACKAGE 24-LEAD (3mm 5mm) PLASTIC QFN = 46C/W JA EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB 3667fb 2 For more information www.linear.com/LT3667 PG1 SW FB1 DA PG2 NC PG3 NC