Datasheet LTC7891 (Analog Devices) - 4

link to page 5 link to page 5 link to page 5 link to page 5 link to page 5 link to page 5 Data Sheet
LTC7891 SPECIFICATIONS Table 1. Electrical Characteristics (Continued) Parameter Symbol Test Conditions/Comments Min Typ Max Unit
GATE DRIVERS TGxx or BGxx On-Resistance DRVSET = INTVCC Pull-Up 2.0 Ω Pull-Down 1.0 Ω BOOST to DRVCC Switch On-Resistance DRVSET = INTVCC 7 Ω TGxx or BGxx Transition Time4 Rise Time 25 ns Fall Time 15 ns TGxx Off to BGxx On Delay4 Synchronous Switch On Delay Time DTCA = 0 V 20 ns BGxx Off to TGxx On Delay4 Top Switch On Delay Time DTCB = 0 V 20 ns BGxx Falling to SW Rising Delay5 DTCA = INTVCC, DTCB = INTVCC or resistor 2 ns DTCA = 50 kΩ, DTCB = INTVCC or resistor 25 ns DTCA = 100 kΩ, DTCB = INTVCC or resistor 40 ns SW Falling to BGxx Rising Delay5 DTCB = INTVCC, DTCA = INTVCC or resistor 0.5 ns DTCB = 50 kΩ, DTCA = INTVCC or resistor 25 ns DTCB = 100 kΩ, DTCA = INTVCC or resistor 40 ns TGxx Minimum On-Time6 tON(MIN) 40 ns Maximum Duty Cycle Output in dropout, FREQ = 0 V 99 % INTVCC LOW DROPOUT (LDO) LINEAR REGULATORS INTVCC Voltage for VIN and EXTVCC LDOs EXTVCC = 0 V for VIN LDO, 12 V for EXTVCC LDO DRVSET = INTVCC 5.2 5.5 5.7 V DRVSET = 0 V 4.8 5.0 5.2 V DRVSET= 64.9 kΩ 4.5 4.75 5.0 V DRVCC Load Regulation DRVCC load current (ICC) = 0 mA to 100 mA, TA = 1 3 % 25°C Undervoltage Lockout UVLO DRVCC Rising DRVUV = INTVCC 4.8 5.0 5.2 V DRVUV = 0 V 3.6 3.8 4.0 V DRVUV = floating 4.2 4.4 4.6 V DRVCC Falling DRVUV = INTVCC 4.55 4.75 4.95 V DRVUV = 0 V 3.4 3.6 3.8 V DRVUV = floating 4.0 4.18 4.4 V EXTVCC LDO Switchover Voltage EXTVCC Rising DRVUV = INTVCC or floating, TA = 25°C 5.75 5.95 6.15 V DRVUV = 0 V, TA = 25°C 4.6 4.76 4.9 V EXTVCC Switchover Hysteresis EXTVCC Falling DRVUV = INTVCC or floating 390 mV DRVUV = 0 V 220 mV
analog.com Rev. A | 4 of 36
Document Outline Features Applications Typical Application Circuit General Description Specifications Electrical Characteristics Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Functional Diagram Main Control Loop Power and Bias Supplies (VIN, EXTVCC, DRVCC, and INTVCC) High-Side Bootstrap Capacitor Dead Time Control (DTCA and DTCB Pins) Startup and Shutdown (RUN and TRACK/SS Pins) Light Load Operation: Burst Mode Operation, Pulse Skipping Mode, or Forced Continuous Mode (MODE Pin) Frequency Selection, Spread Spectrum, and Phase-Locked Loop (FREQ and PLLIN/SPREAD Pins) Output Overvoltage Protection Foldback Current Power Good Applications Information Inductor Value Calculation Inductor Core Selection Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Current Sensing Setting the Operating Frequency Selecting the Light Load Operating Mode Dead Time Control (DTCA and DTCB Pins) DTCx Pins Tied to GND (Adaptive Dead Time Control) DTCx Pins Tied to INTVCC (Smart Near Zero Dead Time Control) DTCx Pins Connected with a Resistor to GND Power FET Selection CIN and COUT Selection Setting the Output Voltage RUN Pin and Undervoltage Lockout Soft Start and Tracking (TRACK/SS Pin) INTVCC Regulators (OPTI-DRIVE) Topside FET Driver Supply (CB) Minimum On Time Considerations Fault Conditions: Current Limit and Foldback Fault Conditions: Overvoltage Protection Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Efficiency Considerations Checking Transient Response Design Example PCB Layout Checklist PCB Layout Debugging Typical Applications Related Products Outline Dimensions Ordering Guide Evaluation Boards Automotive Products