Datasheet LT3668 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | 40V 400mA Step-Down Switching Regulator with Dual Fault Protected Tracking LDOs |
| Pages / Page | 28 / 4 — 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
Dropout Voltage (Notes 9, 10), ILOAD = 1mA 70 165 mV VIN = VOUT(NOMINAL) ILOAD = 1mA l 210 mV ILOAD = 50mA 230 300 mV ILOAD = 50mA l 400 mV ILOAD = 100mA 280 400 mV ILOAD = 100mA l 450 mV ILOAD = 200mA 340 650 mV ILOAD = 200mA l 750 mV GND Pin Current, VIN = VOUT(NOMINAL) + 0.6V ILOAD = 0mA l 40 90 µA (Notes 10, 11) ILOAD = 50mA l 1 2 mA ILOAD = 200mA l 5 10 mA Quiescent Current IIN2 with LDO2 Disabled VIN1 = 0V, VIN2 = 12V, VEN2/ILIM2 = 2V 13 20 µA Quiescent Current IIN3/BD with LDO3 Disabled VIN1 = 16V, VIN3/BD = 12V, VEN3/ILIM3 = 2V 1.2 2 µA ADJ2 Pin Bias Current (Note 10) VADJ2 ≤10V, VADJ2 ≤ VIN2 – 0.6V, VOUT2 ≤ VIN2 – 0.6V l 800 nA ADJ3 Pin Bias Current (Note 10) VADJ3 ≤10V, VADJ3 ≤ VIN3/BD – 0.6V, VOUT3 ≤ VIN3/BD – 0.6V l 800 nA Ripple Rejection VIN – VOUT = 2V (Avg), VRIPPLE = 0.5VP-P, 60 85 dB fRIPPLE = 120Hz, ILOAD =200mA Reverse Output Current (Note 12) VOUT2 = 1.2V, VIN1 = VIN2 = VIN3/BD = 0V 5 40 µA VOUT3 = 1.2V, VIN1 = VIN2 = VIN3/BD = 0V 5 40 µA Input Reverse Leakage Current LDO2 VIN2 = –45V, VIN1 = VIN3/BD = VOUT2 = 0V l 300 µA Internal Current Limit VIN2 = 2.2V, VOUT2 = 0V, EN2/ILIM2 Pin Grounded 300 mA ∆VOUT2 = –5% l 220 mA VIN3/BD = 2.2V, VOUT3 = 0V, EN3/ILIM3 Pin Grounded 300 mA ∆VOUT3 = –5% l 220 mA Externally Programmed Current Limit REN/ILIM = 31.6k, VOUT2/3 = 5V, VIN2/3 ≥ 5.6V l 9.5 10 10.5 mA REN/ILIM = 6.19k, VOUT2/3 = 5V, VIN2/3 ≥ 5.6V l 47 51 55 mA REN/ILIM = 6.19k, VOUT2/3 = 5V, 5.6V ≤ VIN2/3 ≤ 15V l 48.45 51 53.55 mA REN/ILIM = 1.54k, VOUT2/3 = 5V, 5.6V ≤ VIN2/3 ≤ 15V l 176 197 230 mA LDO EN/ILIM Disable Threshold 0.3 1.2 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 6:
This is the voltage necessary to keep the internal bias circuitry in may cause permanent damage to the device. Exposure to any Absolute regulation. Maximum Rating condition for extended periods may affect device
Note 7:
Current limit guaranteed by design and/or correlation to static test. reliability and lifetime. Slope compensation reduces current limit at higher duty cycles.
Note 2:
Positive currents flow into pins, negative currents flow out of pins.
Note 8:
This is the minimum voltage across the boost capacitor needed to Minimum and maximum values refer to absolute values. guarantee full saturation of the switch.
Note 3:
Absolute maximum voltage at the IN1 and EN pins is 60V for
Note 9:
Dropout voltage is the minimum input-to-output voltage nonrepetitive 1 second transients, and 40V for continuous operation. differential needed for an LDO to maintain regulation at a specified output
Note 4:
The LT3668E is guaranteed to meet performance specifications current. When an LDO is in dropout, its output voltage will be equal to from 0°C to 125°C junction temperature. Specifications over the −40°C VIN – VDROP. to 125°C operating junction temperature range are assured by design,
Note 10:
The LT3668 is tested and specified for these conditions with characterization and correlation with statistical process controls. The VADJ2/3 = 5V. LT3668I is guaranteed over the full −40°C to 125°C operating junction
Note 11:
GND pin current is tested with V temperature range. The LT3668H is guaranteed over the full −40°C to IN = VOUT(NOMINAL) + 0.6V and a current source load. GND pin current increases in dropout. 150°C operating junction temperature range.
Note 12:
Reverse output current is tested with the IN2 (IN3/BD) pin
Note 5:
This IC includes overtemperature protection that is intended to protect grounded and the OUT2 (OUT3) pin forced to the rated output voltage. the device during momentary overload conditions. Junction temperature will This current flows into the OUT2 (OUT3) pin and out of the GND pin. exceed the maximum operating junction temperature when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 3668fa 4 For more information www.linear.com/LT3668 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
Dropout Voltage (Notes 9, 10), ILOAD = 1mA 70 165 mV VIN = VOUT(NOMINAL) ILOAD = 1mA l 210 mV ILOAD = 50mA 230 300 mV ILOAD = 50mA l 400 mV ILOAD = 100mA 280 400 mV ILOAD = 100mA l 450 mV ILOAD = 200mA 340 650 mV ILOAD = 200mA l 750 mV GND Pin Current, VIN = VOUT(NOMINAL) + 0.6V ILOAD = 0mA l 40 90 µA (Notes 10, 11) ILOAD = 50mA l 1 2 mA ILOAD = 200mA l 5 10 mA Quiescent Current IIN2 with LDO2 Disabled VIN1 = 0V, VIN2 = 12V, VEN2/ILIM2 = 2V 13 20 µA Quiescent Current IIN3/BD with LDO3 Disabled VIN1 = 16V, VIN3/BD = 12V, VEN3/ILIM3 = 2V 1.2 2 µA ADJ2 Pin Bias Current (Note 10) VADJ2 ≤10V, VADJ2 ≤ VIN2 – 0.6V, VOUT2 ≤ VIN2 – 0.6V l 800 nA ADJ3 Pin Bias Current (Note 10) VADJ3 ≤10V, VADJ3 ≤ VIN3/BD – 0.6V, VOUT3 ≤ VIN3/BD – 0.6V l 800 nA Ripple Rejection VIN – VOUT = 2V (Avg), VRIPPLE = 0.5VP-P, 60 85 dB fRIPPLE = 120Hz, ILOAD =200mA Reverse Output Current (Note 12) VOUT2 = 1.2V, VIN1 = VIN2 = VIN3/BD = 0V 5 40 µA VOUT3 = 1.2V, VIN1 = VIN2 = VIN3/BD = 0V 5 40 µA Input Reverse Leakage Current LDO2 VIN2 = –45V, VIN1 = VIN3/BD = VOUT2 = 0V l 300 µA Internal Current Limit VIN2 = 2.2V, VOUT2 = 0V, EN2/ILIM2 Pin Grounded 300 mA ∆VOUT2 = –5% l 220 mA VIN3/BD = 2.2V, VOUT3 = 0V, EN3/ILIM3 Pin Grounded 300 mA ∆VOUT3 = –5% l 220 mA Externally Programmed Current Limit REN/ILIM = 31.6k, VOUT2/3 = 5V, VIN2/3 ≥ 5.6V l 9.5 10 10.5 mA REN/ILIM = 6.19k, VOUT2/3 = 5V, VIN2/3 ≥ 5.6V l 47 51 55 mA REN/ILIM = 6.19k, VOUT2/3 = 5V, 5.6V ≤ VIN2/3 ≤ 15V l 48.45 51 53.55 mA REN/ILIM = 1.54k, VOUT2/3 = 5V, 5.6V ≤ VIN2/3 ≤ 15V l 176 197 230 mA LDO EN/ILIM Disable Threshold 0.3 1.2 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 6:
This is the voltage necessary to keep the internal bias circuitry in may cause permanent damage to the device. Exposure to any Absolute regulation. Maximum Rating condition for extended periods may affect device
Note 7:
Current limit guaranteed by design and/or correlation to static test. reliability and lifetime. Slope compensation reduces current limit at higher duty cycles.
Note 2:
Positive currents flow into pins, negative currents flow out of pins.
Note 8:
This is the minimum voltage across the boost capacitor needed to Minimum and maximum values refer to absolute values. guarantee full saturation of the switch.
Note 3:
Absolute maximum voltage at the IN1 and EN pins is 60V for
Note 9:
Dropout voltage is the minimum input-to-output voltage nonrepetitive 1 second transients, and 40V for continuous operation. differential needed for an LDO to maintain regulation at a specified output
Note 4:
The LT3668E is guaranteed to meet performance specifications current. When an LDO is in dropout, its output voltage will be equal to from 0°C to 125°C junction temperature. Specifications over the −40°C VIN – VDROP. to 125°C operating junction temperature range are assured by design,
Note 10:
The LT3668 is tested and specified for these conditions with characterization and correlation with statistical process controls. The VADJ2/3 = 5V. LT3668I is guaranteed over the full −40°C to 125°C operating junction
Note 11:
GND pin current is tested with V temperature range. The LT3668H is guaranteed over the full −40°C to IN = VOUT(NOMINAL) + 0.6V and a current source load. GND pin current increases in dropout. 150°C operating junction temperature range.
Note 12:
Reverse output current is tested with the IN2 (IN3/BD) pin
Note 5:
This IC includes overtemperature protection that is intended to protect grounded and the OUT2 (OUT3) pin forced to the rated output voltage. the device during momentary overload conditions. Junction temperature will This current flows into the OUT2 (OUT3) pin and out of the GND pin. exceed the maximum operating junction temperature when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 3668fa 4 For more information www.linear.com/LT3668 Document Outline Features Applications Description Typical Application Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Related Parts
