LTC3350_15 Datasheet, PDF (2/46 Pages) Linear Technology – High Current Supercapacitor Backup Controller and System Monitor

LTC3350
Table of Contents
Features...................................................... 1
Applications................................................. 1
Typical Application ......................................... 1
Description.................................................. 1
Absolute Maximum Ratings............................... 3
Order Information........................................... 3
Pin Configuration........................................... 3
Electrical Characteristics.................................. 4
Typical Performance Characteristics.................... 7
Pin Functions............................................... 10
Block Diagram.............................................. 13
Timing Diagram............................................ 14
Operation................................................... 14
Introduction............................................................. 14
Bidirectional Switching Controller—Step-Down
Mode....................................................................... 14
Bidirectional Switching Controller—Step-Up Mode.15
Ideal Diodes............................................................. 16
Gate Drive Supply (DRV_CC) ..................................... 17
Undervoltage Lockout (UVLO) ................................ 17
RT Oscillator and Switching Frequency................... 17
Input Overvoltage Protection .................................. 17
V_CAP DAC ................................................................ 17
Power-Fail (PF) Comparator.................................... 17
Charge Status Indication......................................... 17
Capacitor Voltage Balancer ..................................... 17
Capacitor Shunt Regulators..................................... 18
I²C/SMBus and SMBALERT..................................... 18
Analog-to-Digital Converter..................................... 18
Capacitance and ESR Measurement ....................... 18
Monitor Status Register........................................... 19
Charge Status Register............................................20
Limit Checking and Alarms......................................20
Die Temperature Sensor..........................................20
General Purpose Input.............................................20
Applications Information................................. 21
Digital Configuration................................................ 21
Capacitor Configuration........................................... 21
Capacitor Shunt Regulator Programming................ 21
Setting Input and Charge Currents.......................... 21
Low Current Charging and High Current Backup.....22
Setting V_CAP Voltage................................................22
Power-Fail Comparator Input Voltage Threshold ....22
Setting V_OUT Voltage in Backup Mode.....................23
Compensation.......................................................... 24
Minimum V_CAP Voltage in Backup Mode.................. 24
Optimizing Supercapacitor Energy Storage Capacity...
25
Capacitor Selection Procedure ................................26
Inductor Selection...................................................26
C_OUT and C_CAP Capacitance..................................... 27
Power MOSFET Selection........................................ 28
Schottky Diode Selection......................................... 28
Top MOSFET Driver Supply (C_B, D_B)........................29
INTV_CC/DRV_CC and IC Power Dissipation................29
Minimum On-Time Considerations..........................30
Ideal Diode MOSFET Selection................................30
PCB Layout Considerations.....................................30
Register Map............................................... 32
Register Descriptions..................................... 33
Typical Applications....................................... 39
Package Description...................................... 44
Revision History........................................... 45
Typical Application........................................ 46
Related Parts............................................... 46
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