Linear Technology LTC3350, Руководство пользователя

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LTC3350
2
3350fc
For more information www.linear.com/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
I
2
C/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