Datasheet LT3668 (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | 40V 400mA Step-Down Switching Regulator with Dual Fault Protected Tracking LDOs |
| Pages / Page | 28 / 3 — ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply … |
| File Format / Size | PDF / 386 Kb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS The. denotes the specifications which apply over the full operating
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LT3668
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN1 = 12V unless otherwise noted. (Note 4) PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN1 Undervoltage Lockout (Note 6) VIN2 = 0V, VIN3/BD = 0V l 4 4.3 V VIN1 Overvoltage Lockout l 40 42 44 V VIN2 Undervoltage Lockout (Note 6) VIN1 = 3.5V, VIN3/BD = 0V l 4 4.3 V Quiescent Current from IN1 VEN = 0.3V 0.01 1 µA VEN = 12V, VIN2 = 0V, Not Switching l 13 30 µA Quiescent Current from IN2 VEN = 0.3V 0.01 1 µA VEN = 12V, VIN1 = 0V, VIN2 = 5V l 38 80 µA Quiescent Current from IN1 + IN2 VEN = 0.3V, VIN2 = 5V 0.01 1 µA VEN = 12V, VIN2 = 5V, Not Switching l 40 90 µA Quiescent Current from IN3/BD VEN = 0.3V, VIN3/BD = 5V 0.01 1 µA VEN = 12V, VIN3/BD = 5V l 25 60 µA EN Pin Current VEN = 12V 0.6 2 µA EN Input Threshold 0.3 1.1 V
Power Good Pin PG
Leakage Current VPG = 5V 0.1 1 µA Output Voltage Low IPG = 40µA l 0.2 0.3 V Threshold as % of VFB1 Pin Voltage Falling 88 90 92 % Pin Voltage Rising 108 110 112 % PG Threshold Hysteresis Measured at FB1 Pin 30 mV
Switching Regulator
Switching Frequency RT = 37.4k l 1.8 2.0 2.1 MHz RT = 102k l 0.8 0.94 1.1 MHz RT = 487k l 220 243 300 kHz Minimum Switch Off-Time l 120 190 ns Switch Current Limit (Note 7) 5% Duty Cycle, VIN = 5V, VFB1 = 0V l 600 750 950 mA 90% Duty Cycle, VIN = 5V, VFB1 = 0V l 450 550 800 mA Switch VCESAT ISW = 200mA 300 mV DA Pin Current to Stop Switching l 420 500 650 mA Switch Leakage Current VSW = 0V 0.05 2 µA Boost Schottky Diode Forward Voltage IBOOSTDIODE = 50mA, VIN = NC, VBOOST = 0V 900 mV Boost Schottky Diode Reverse Leakage VREVERSE = 12V, VIN = NC 0.04 4 µA Minimum Boost Voltage (Note 8) l 1.7 2.5 V BOOST Pin Current ISW = 200mA, VBOOST = 15V 10 16 mA Feedback Voltage (FB1) 1.188 1.2 1.212 V l 1.176 1.2 1.224 mV FB1 Pin Bias Current Pin Voltage = 1.2V l 0.1 20 nA Reference Voltage Line Regulation 4.2V < VIN1 < 40V 0.001 0.005 %/V
Each LDO Regulator
Minimum Input Voltage ILOAD = 200mA l 1.6 2.2 V Output Voltage Range l 1.1 10 V Tracking Error VOUT2/3-VADJ2/3 1.1V ≤ VADJ2/3 ≤ 5V, ILOAD = 1mA –40°C to 125°C l –6 6 mV 5V < VADJ2/3 ≤ 10V, ILOAD = 1mA –40°C to 125°C l –20 50 mV 1.1V ≤ VADJ2/3 ≤ 5V, ILOAD = 1mA –40°C to 150°C l –6 15 mV 5V < VADJ2/3 ≤ 10V, ILOAD = 1mA –40°C to 150°C l –20 80 mV 3668fa For more information www.linear.com/LT3668 3 Document Outline Features Applications Description Typical Application Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN1 = 12V unless otherwise noted. (Note 4) PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN1 Undervoltage Lockout (Note 6) VIN2 = 0V, VIN3/BD = 0V l 4 4.3 V VIN1 Overvoltage Lockout l 40 42 44 V VIN2 Undervoltage Lockout (Note 6) VIN1 = 3.5V, VIN3/BD = 0V l 4 4.3 V Quiescent Current from IN1 VEN = 0.3V 0.01 1 µA VEN = 12V, VIN2 = 0V, Not Switching l 13 30 µA Quiescent Current from IN2 VEN = 0.3V 0.01 1 µA VEN = 12V, VIN1 = 0V, VIN2 = 5V l 38 80 µA Quiescent Current from IN1 + IN2 VEN = 0.3V, VIN2 = 5V 0.01 1 µA VEN = 12V, VIN2 = 5V, Not Switching l 40 90 µA Quiescent Current from IN3/BD VEN = 0.3V, VIN3/BD = 5V 0.01 1 µA VEN = 12V, VIN3/BD = 5V l 25 60 µA EN Pin Current VEN = 12V 0.6 2 µA EN Input Threshold 0.3 1.1 V
Power Good Pin PG
Leakage Current VPG = 5V 0.1 1 µA Output Voltage Low IPG = 40µA l 0.2 0.3 V Threshold as % of VFB1 Pin Voltage Falling 88 90 92 % Pin Voltage Rising 108 110 112 % PG Threshold Hysteresis Measured at FB1 Pin 30 mV
Switching Regulator
Switching Frequency RT = 37.4k l 1.8 2.0 2.1 MHz RT = 102k l 0.8 0.94 1.1 MHz RT = 487k l 220 243 300 kHz Minimum Switch Off-Time l 120 190 ns Switch Current Limit (Note 7) 5% Duty Cycle, VIN = 5V, VFB1 = 0V l 600 750 950 mA 90% Duty Cycle, VIN = 5V, VFB1 = 0V l 450 550 800 mA Switch VCESAT ISW = 200mA 300 mV DA Pin Current to Stop Switching l 420 500 650 mA Switch Leakage Current VSW = 0V 0.05 2 µA Boost Schottky Diode Forward Voltage IBOOSTDIODE = 50mA, VIN = NC, VBOOST = 0V 900 mV Boost Schottky Diode Reverse Leakage VREVERSE = 12V, VIN = NC 0.04 4 µA Minimum Boost Voltage (Note 8) l 1.7 2.5 V BOOST Pin Current ISW = 200mA, VBOOST = 15V 10 16 mA Feedback Voltage (FB1) 1.188 1.2 1.212 V l 1.176 1.2 1.224 mV FB1 Pin Bias Current Pin Voltage = 1.2V l 0.1 20 nA Reference Voltage Line Regulation 4.2V < VIN1 < 40V 0.001 0.005 %/V
Each LDO Regulator
Minimum Input Voltage ILOAD = 200mA l 1.6 2.2 V Output Voltage Range l 1.1 10 V Tracking Error VOUT2/3-VADJ2/3 1.1V ≤ VADJ2/3 ≤ 5V, ILOAD = 1mA –40°C to 125°C l –6 6 mV 5V < VADJ2/3 ≤ 10V, ILOAD = 1mA –40°C to 125°C l –20 50 mV 1.1V ≤ VADJ2/3 ≤ 5V, ILOAD = 1mA –40°C to 150°C l –6 15 mV 5V < VADJ2/3 ≤ 10V, ILOAD = 1mA –40°C to 150°C l –20 80 mV 3668fa For more information www.linear.com/LT3668 3 Document Outline Features Applications Description Typical Application Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts
