LTC1473L Datasheet, PDF (1/16 Pages) Linear Technology – Dual Low Voltage PowerPathTM Switch Driver

LTC1473L
Dual Low Voltage
PowerPath^TM Switch Driver
FEATURES
s _{Power Path Management for Systems}
with Multiple DC Sources
s _{Switches and Isolates Sources from 3.3V to 10V}
s _{All N-Channel Switching to Reduce Power Losses}
and System Cost
s _{Built-In Step-Up Regulator for N-Channel Gate Drive}
s _{Capacitor Inrush and Short-Circuit Current Limited}
s _{User-Programmable Timer Prevents Overdissipation}
During Current Limiting
s _{Undervoltage Lockout Prevents Operation with Low}
Inputs
s _{Small Footprint: 16-Pin Narrow SSOP}
U
APPLICATIO S
s _{Portable Computers}
s _{Portable Instruments}
s _{Fault Tolerant Computers}
s _{Battery-Backup Systems}
s _{3.3V/5V Power Management}
DESCRIPTIO
The LTC^®1473L provides reliable and efficient switching
between two DC power sources. This device drives two
external sets of back-to-back N-channel MOSFET switches
to route power to the input of a low voltage system. An
internal boost regulator provides the voltage to fully en-
hance the logic-level N-channel MOSFET switches while
an internal undervoltage lock-out circuit keeps the system
alive down to 2.8V.
The LTC1473L senses current to limit inrush between the
batteries and the system supply capacitor during switch-
over transitions or during fault conditions. A user-pro-
grammable timer monitors the time the MOSFET switches
are in current limit and latches them off when the pro-
grammed time is exceeded.
A unique “2-diode” logic mode ensures system start-up
regardless of which input receives power first.
, LTC and LT are registered trademarks of Linear Technology Corporation.
PowerPath is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
DCIN
3.3V
V_BAT1
4× NiMH
BAT54C
C_TIMER
2000pF
1µF
1µF
3.3V to 4-Cell NiMH Backup Switch
Si9926DY
LOGIC
DRIVEN
1mH*
1
LTC1473L
16
IN1
GA1
2
IN2
15
SAB1
3
DIODE
14
GB1
4
TIMER
SENSE^{+ 13}
5 _V+
SENSE^{– 12}
6
V_GG
11
GA2
7
SW
10
SAB2
8
GND
9
GB2
R_SENSE
0.04Ω
3.3V OR
+
V_BAT1
C_OUT
* COILCRAFT 1812LS-105XKBC
Si9926DY
1473 TA01
1