Datasheet LT8642S (Analog Devices) - 3
| Manufacturer | Analog Devices |
| Description | 18V, 10A Synchronous Step-Down Silent Switcher 2 |
| Pages / Page | 26 / 3 — ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply … |
| File Format / Size | PDF / 1.4 Mb |
| Document Language | English |
ELECTRICAL CHARACTERISTICS. The. denotes the specifications which apply over the full operating
Model Line for this Datasheet
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link to page 13 link to page 13 LT8642S
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS
VC Source Current VFB = 0.4V, VC = 1.25V 360 µA VC Sink Current VFB = 0.8V, VC = 1.25V 360 µA VC Pin to Switch Current Gain 8.5 A/V VC Clamp Voltage 2.6 V BIAS Pin Current Consumption VBIAS = 3.3V, fSW = 2MHz 20 mA Minimum On-Time ILOAD = 3A, SYNC = 2V l 20 35 ns Minimum Off-Time 80 110 ns Oscillator Frequency RT = 221k l 175 210 245 kHz RT = 60.4k l 655 700 745 kHz RT = 18.2k l 1.875 1.95 2.025 MHz Top Power NMOS On-Resistance 17.5 mΩ Top Power NMOS Current Limit l 14.5 18 21.5 A Bottom Power NMOS On-Resistance VINTVCC = 3.4V 8 mΩ Bottom Power NMOS Current Limit VINTVCC = 3.4V 10.5 13.5 16 A SW Leakage Current VIN = 18V, VSW = 0V, 18V –15 15 µA EN/UV Pin Threshold EN/UV Rising l 0.93 0.99 1.05 V EN/UV Pin Hysteresis 40 mV EN/UV Pin Current VEN/UV = 2V –20 20 nA PG Upper Threshold Offset from VFB VFB Rising l 5 8 11 % PG Lower Threshold Offset from VFB VFB Falling l –5.5 –8.5 –11.5 % PG Hysteresis 0.4 % PG Leakage VPG = 3.3V –40 40 nA PG Pull-Down Resistance VPG = 0.1V l 650 2000 Ω SYNC/MODE Threshold SYNC/MODE DC and Clock Low Level Voltage l 0.7 V SYNC/MODE Clock High Level Voltage l 1.4 V SYNC/MODE DC High Level Voltage l 2.2 2.9 V Spread Spectrum Modulation RT = 60.4k, VSYNC = 3.3V 22 % Frequency Range Spread Spectrum Modulation Frequency VSYNC = 3.3V 3 kHz SS Source Current l 1.2 1.9 2.6 µA SS Pull-Down Resistance Fault Condition, SS = 0.1V 220 Ω
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
θ values determined per JEDEC 51-7, 51-12. See the Applications may cause permanent damage to the device. Exposure to any Absolute Information section for information on improving the thermal resistance Maximum Rating condition for extended periods may affect device and for actual temperature measurements of a demo board in typical reliability and lifetime. operating conditions.
Note 2:
The LT8642SE is guaranteed to meet performance specifications
Note 4:
This IC includes overtemperature protection that is intended to from 0°C to 125°C junction temperature. Specifications over the –40°C protect the device during overload conditions. Junction temperature will to 125°C operating junction temperature range are assured by design, exceed 150°C when overtemperature protection is active. Continuous characterization, and correlation with statistical process controls. The operation above the specified maximum operating junction temperature LT8642SI is guaranteed over the full –40°C to 125°C operating junction will reduce lifetime. temperature range. The junction temperature (TJ, in °C) is calculated from the ambient temperature (TA in °C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD • θJA) where θJA (in °C/W) is the package thermal impedance. Rev 0 For more information www.analog.com 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Applications Related Parts
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. PARAMETER CONDITIONS MIN TYP MAX UNITS
VC Source Current VFB = 0.4V, VC = 1.25V 360 µA VC Sink Current VFB = 0.8V, VC = 1.25V 360 µA VC Pin to Switch Current Gain 8.5 A/V VC Clamp Voltage 2.6 V BIAS Pin Current Consumption VBIAS = 3.3V, fSW = 2MHz 20 mA Minimum On-Time ILOAD = 3A, SYNC = 2V l 20 35 ns Minimum Off-Time 80 110 ns Oscillator Frequency RT = 221k l 175 210 245 kHz RT = 60.4k l 655 700 745 kHz RT = 18.2k l 1.875 1.95 2.025 MHz Top Power NMOS On-Resistance 17.5 mΩ Top Power NMOS Current Limit l 14.5 18 21.5 A Bottom Power NMOS On-Resistance VINTVCC = 3.4V 8 mΩ Bottom Power NMOS Current Limit VINTVCC = 3.4V 10.5 13.5 16 A SW Leakage Current VIN = 18V, VSW = 0V, 18V –15 15 µA EN/UV Pin Threshold EN/UV Rising l 0.93 0.99 1.05 V EN/UV Pin Hysteresis 40 mV EN/UV Pin Current VEN/UV = 2V –20 20 nA PG Upper Threshold Offset from VFB VFB Rising l 5 8 11 % PG Lower Threshold Offset from VFB VFB Falling l –5.5 –8.5 –11.5 % PG Hysteresis 0.4 % PG Leakage VPG = 3.3V –40 40 nA PG Pull-Down Resistance VPG = 0.1V l 650 2000 Ω SYNC/MODE Threshold SYNC/MODE DC and Clock Low Level Voltage l 0.7 V SYNC/MODE Clock High Level Voltage l 1.4 V SYNC/MODE DC High Level Voltage l 2.2 2.9 V Spread Spectrum Modulation RT = 60.4k, VSYNC = 3.3V 22 % Frequency Range Spread Spectrum Modulation Frequency VSYNC = 3.3V 3 kHz SS Source Current l 1.2 1.9 2.6 µA SS Pull-Down Resistance Fault Condition, SS = 0.1V 220 Ω
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 3:
θ values determined per JEDEC 51-7, 51-12. See the Applications may cause permanent damage to the device. Exposure to any Absolute Information section for information on improving the thermal resistance Maximum Rating condition for extended periods may affect device and for actual temperature measurements of a demo board in typical reliability and lifetime. operating conditions.
Note 2:
The LT8642SE is guaranteed to meet performance specifications
Note 4:
This IC includes overtemperature protection that is intended to from 0°C to 125°C junction temperature. Specifications over the –40°C protect the device during overload conditions. Junction temperature will to 125°C operating junction temperature range are assured by design, exceed 150°C when overtemperature protection is active. Continuous characterization, and correlation with statistical process controls. The operation above the specified maximum operating junction temperature LT8642SI is guaranteed over the full –40°C to 125°C operating junction will reduce lifetime. temperature range. The junction temperature (TJ, in °C) is calculated from the ambient temperature (TA in °C) and power dissipation (PD, in Watts) according to the formula: TJ = TA + (PD • θJA) where θJA (in °C/W) is the package thermal impedance. Rev 0 For more information www.analog.com 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Electrical Characteristics Pin Configuration Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Applications Related Parts
