Datasheet LT3640 (Analog Devices) - 4
| Manufacturer | Analog Devices |
| Description | Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer |
| Pages / Page | 24 / 4 — The. denotes the specifications which apply over the full operating |
| File Format / Size | PDF / 523 Kb |
| Document Language | English |
The. denotes the specifications which apply over the full operating
Model Line for this Datasheet
Text Version of Document
LT3640 elecTrical characTerisTics
The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VIN2 = 3.3V, EN/UVLO = 12V, EN2 = 3.3V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
SS1, SS2 Charge Current SS1 = 0.5V, SS2 = 0.5V 1.4 1.9 2.5 µA SS1 to FB1 Offset Voltage SS1 = 0.6V 5 30 mV SS2 to FB2 Offset Voltage SS2 = 0.3V 5 30 mV RST1 Threshold as Percentage of VFB l 90 92 94 % RST2 Threshold as Percentage of VFB l 89 92 94 % Undervoltage to RST Assert Time 20 µs RST1, RST2, WDO Pull-Up Current RST1, RST2, WDO = 0V 5 15 30 µA RST1, RST2, WDO Output Voltage IRST1, IRST2, IWDO = 2mA 150 250 mV RST1, RST2 Timeout Period (tRST) CPOR = 220pF l 8 9.5 11 ms Watchdog Start Delay Time (tDLY) CWDT = 820pF 14 16 18 ms Watchdog Upper Boundary (tWDU) CWDT = 820pF l 27 32 35 ms Watchdog Lower Boundary (tWDL) CWDT = 820pF l 1.68 2 2.2 ms WDI Pull-Up Current WDI = 1.2V 2 µA WDI Voltage Threshold 0.55 0.85 1.15 V WDI Low Minimum Pulse Width 300 ns WDI High Minimum Pulse Width 300 ns WDE Pull-Down Current WDE = 2V 1 µA WDE Threshold l 0.5 0.7 0.9 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
SW1, SW2 current limit is guaranteed by design and/or correlation may cause permanent damage to the device. Exposure to any Absolute to static test. Slope compensation reduces current limit at higher duty Maximum Rating condition for extended periods may affect device cycle. reliability and lifetime.
Note 4:
The oscillator cycle is extended when DA current exceeds its limit.
Note 2:
The LT3640E is guaranteed to meet performance specifications DA current limit is flat over duty cycle. from 0°C to 125°C junction temperature. Specifications over the –40°C
Note 5:
If the SW2 NMOS current exceeds its limit at the start of an to 125°C operating junction temperature range are assured by design, oscillator cycle, the PMOS will not be turned on in the cycle. characterization and correlation with statistical process controls. The
Note 6:
The QFN switch R LT3640I is guaranteed and tested over the full –40°C to 125°C operating DS(ON) is guaranteed by correlation to wafer level measurement. junction temperature range.
Note 7:
Absolute maximum voltage at VIN and RUN/SS pin is 55V for nonrepetitive one second transients, and 36V for continuous operation. 3640f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Operation Applications Information Typical Applications Package Description Typical Application Related Parts
The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VIN2 = 3.3V, EN/UVLO = 12V, EN2 = 3.3V, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS
SS1, SS2 Charge Current SS1 = 0.5V, SS2 = 0.5V 1.4 1.9 2.5 µA SS1 to FB1 Offset Voltage SS1 = 0.6V 5 30 mV SS2 to FB2 Offset Voltage SS2 = 0.3V 5 30 mV RST1 Threshold as Percentage of VFB l 90 92 94 % RST2 Threshold as Percentage of VFB l 89 92 94 % Undervoltage to RST Assert Time 20 µs RST1, RST2, WDO Pull-Up Current RST1, RST2, WDO = 0V 5 15 30 µA RST1, RST2, WDO Output Voltage IRST1, IRST2, IWDO = 2mA 150 250 mV RST1, RST2 Timeout Period (tRST) CPOR = 220pF l 8 9.5 11 ms Watchdog Start Delay Time (tDLY) CWDT = 820pF 14 16 18 ms Watchdog Upper Boundary (tWDU) CWDT = 820pF l 27 32 35 ms Watchdog Lower Boundary (tWDL) CWDT = 820pF l 1.68 2 2.2 ms WDI Pull-Up Current WDI = 1.2V 2 µA WDI Voltage Threshold 0.55 0.85 1.15 V WDI Low Minimum Pulse Width 300 ns WDI High Minimum Pulse Width 300 ns WDE Pull-Down Current WDE = 2V 1 µA WDE Threshold l 0.5 0.7 0.9 V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
SW1, SW2 current limit is guaranteed by design and/or correlation may cause permanent damage to the device. Exposure to any Absolute to static test. Slope compensation reduces current limit at higher duty Maximum Rating condition for extended periods may affect device cycle. reliability and lifetime.
Note 4:
The oscillator cycle is extended when DA current exceeds its limit.
Note 2:
The LT3640E is guaranteed to meet performance specifications DA current limit is flat over duty cycle. from 0°C to 125°C junction temperature. Specifications over the –40°C
Note 5:
If the SW2 NMOS current exceeds its limit at the start of an to 125°C operating junction temperature range are assured by design, oscillator cycle, the PMOS will not be turned on in the cycle. characterization and correlation with statistical process controls. The
Note 6:
The QFN switch R LT3640I is guaranteed and tested over the full –40°C to 125°C operating DS(ON) is guaranteed by correlation to wafer level measurement. junction temperature range.
Note 7:
Absolute maximum voltage at VIN and RUN/SS pin is 55V for nonrepetitive one second transients, and 36V for continuous operation. 3640f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Operation Applications Information Typical Applications Package Description Typical Application Related Parts
