LTC1623 Linear Technology, LTC1623 Datasheet - Page 9

• Manufacturer Part Number: LTC1623
• Description: SMBus Dual High Side Switch Controller
• Manufacturer: Linear Technology

APPLICATIONS
(PROGRAMMABLE)
To avoid turning on the external power MOSFETs too
quickly, an internal 10k resistor has been placed in series
with each of the output gate drive pins (see Functional
Block Diagram). Therefore, it only needs an external 0.1 F
capacitor to create enough RC delay (10k • 0.1 F = 1ms)
to slow down the ramp rate of the output gate drive. In
other words, it will take a minimum of 1ms to charge up
the external MOSFET. An additional external 1k resistor
between the 0.1 F capacitor and the gate of the MOSFET
(Figure 3) is required to eliminate possible MOSFET self
oscillations.
SMBus)
(FROM SMBus)
(FROM
Figure 3. Dual Load Switch with Q2 On upon Power-Up
(PROGRAMMABLE)
10 F
Figure 5. SMBus Controlled Low Dropout Regulator
10 F
AD0
CLK
DATA
AD1
3.5V TO 5.5V
LTC1623
GND
V
V
CC
CC
U
CLK
DATA
AD0
AD1
GA
GB
2.7V TO 5.5V
LTC1623
GND
V
V
CC
CC
INFORMATION
U
0.1 F
LT1431
GB
GA
1
5
3
6
680
8
0.1 F
1k
W
1k
510pF
DISPLAY
Q1
Si3442DV
Si3442DV
10k
3.3k
1623 TA03
0.1 F
1k
U
Si3442DV
+
FAN
470 F
6V
Q2
Si6433DQ
V
3.3V
SWITCHED
V
3.3V
1623 F03
OUT
OUT
(PROGRAMMABLE)
For active-low applications in which the load needs to be
on upon power-up, an external P-channel switch can be
used (Figure 3). This load can be switched off later after the
proper protocol has been sent.
Used with the LT
extremely low voltage drop regulator (Figures 4 and 5). In
this application, the other output channel can be used to
drive a separate load, or it can also be used to control the
output of the LDO so that the user has total control over the
switching in and switching out of the LDO (Figure 5). Also,
with the help of the LT1304-5, the LTC1623 can be used
to make a boost switching regulator with a low standby
current of 22 A (Figure 6).
(FROM SMBus)
(PROGRAMMABLE)
*SUMIDA CD54-220
10 F
Figure 4. 3.3V/3A Extremely Low Voltage Drop
Regulator and Load Switch
Figure 6. Switching Regulator with Low-Battery
Detect Using 22 A Standby Current
SMBus)
(FROM
10 F
CLK
DATA
AD0
AD1
3.5V TO 5.5V
LTC1623
+
GND
V
AD0
V
CLK
DATA
AD1
®
CC
CC
2.7V TO 4.5V
1431, the LTC1623 makes a 3.3V/3A
LTC1623
100 F
GND
V
V
GA
GB
CC
CC
GA
GB
LT1431
1
5
499k
604k
3
6
SHDN
680
LT1304-5
8
0.1 F
3
7
Si3442DV
22 H*
4
5
510pF
8
2
1N5817
100k
Si3442DV
3.3k
10k
0.1 F
LBO
LTC1623
1k
+
1k
+
470 F
6V
2200 F
V
3.3V
5V
200mA
OUT
LOAD
1623 F05
LOAD
Si3442DV
Si3442DV
9
1623 F04