LTC1623
SMBus Dual High Side
Switch Controller
FEATURES
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DESCRIPTION
The LTC
®
1623 SMBus switch controller is a slave device
that controls two high-side N-channel MOSFETs on either
the SMBus or the I
2
C bus. The LTC1623 operates with an
input voltage from 2.7V to 5.5V with a low standby current
of 14µA (at 3.3V). In accordance with the SMBus specifi-
cation, the LTC1623 maintains the 0.6V V
IL
and 1.4V V
IH
input thresholds throughout the supply voltage range.
Using the 2-wire interface, CLK and DATA, the LTC1623
monitors the bus for a start condition (DATA going from
high to low while CLK is high). Once detected, the LTC1623
compares its address with the first (address) byte sent
over the bus from the master. If matched, the LTC1623 will
execute the second (command) byte from the master and
independently control the built-in charge pumps to drive
two external switches.
The LTC1623 has two three-state programmable address
pins, thus allowing eight different addresses and a total of
sixteen available switches on the same bus.
, LTC and LT are registered trademarks of Linear Technology Corporation.
SMBus and I
2
C Compatible
Built-In Charge Pumps Drive N-Channel Switches
16 Available Switches on the Same Bus
0.6V V
IL
and 1.4V V
IH
for DATA and CLK
Available in 8-Lead MSOP and S0 Packages
Low Standby Current: 14µA
Eight Addresses from Two Three-State Address Pins
Internal Power-On Reset Timer
Internal Undervoltage Lockout
No Need for External Pull-Up Resistors at Output
No Need for Secondary Power Source
APPLICATIONS
s
s
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s
Computer Peripheral Control
Laptop Computer Power Plane Switching
Portable Equipment Power Control
Industrial Control Systems
Handheld Equipment
TYPICAL APPLICATION
V
CC
2.7V TO 5.5V
14
10µF
V
CC
(FROM
SMBus)
CLK
DATA
LTC1623
(PROGRAMMABLE)
AD0
AD1
GND
LOAD1
LOAD2
GA
GB
Q1
Q2
*
12
T
J
= 25°C
GATE VOLTAGE (V)
10
8
6
4
2
0
0
1
2
3
4
SUPPLY VOLTAGE (V)
5
6
1623 G01
* SILICONIX Si69260Q
1623 TA01
U
U
U
Gate Drive Voltage
1
LTC1623
ABSOLUTE
MAXIMUM
RATINGS
(Voltages Referred to GND Pin)
Input Supply Voltage (V
CC
) ..........................– 0.3V to 6V
DATA, CLK (Bus Pins 1, 2) ..........................– 0.3V to 6V
AD0, AD1 (Address Pins 3, 5) ..... – 0.3V to (V
CC
+ 0.3V)
GA,GB (Gate Drive Pins 6, 7) .......... – 0.3V to (V
CC
+ 7V)
Junction Temperature ........................................... 125°C
Operating Temperature Range
LTC1623C.................................................. 0° to 70°C
LTC1623I ............................................ –40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
DATA
CLK
AD0
GND
1
2
3
4
8
7
6
5
V
CC
GA
GB
AD1
ORDER PART
NUMBER
DATA 1
LTC1623CMS8
MS8 PART MARKING
LTCH
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 150°C/ W
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
CC
I
VCC
Operating Supply Voltage Range
Supply Current
T
A
= 25°C, V
CC
= 5V unless otherwise specified. C
GA
= 1000pF, C
GB
= 1000pF
MIN
2.7
q
q
q
q
q
q
q
q
q
CONDITIONS
Charge Pump Off, AD0 and AD1High or Low, V
CC
= 2.7V
DATA and CLK High
V
CC
= 3.3V
V
CC
= 5V
GA or GB High (Command Byte 00000001 or 00000010)
Both GA and GB High (Command Byte 00000011)
V
CC
= 2.7V
V
CC
= 3.3V
V
CC
= 5.5V
Falling Edge (Note1)
V
CC
= 2.7V (Note2)
V
CC
= 5.5V
I
VCC
V
GS
Supply Current
Gate Voltage Above Supply
V
UVLO
t
POR
f
OSC
t
ON
t
OFF
V
IL
V
IH
Undervoltage Lockout
Power-On Reset Delay Time
Charge Pump Oscillator Frequency
(Note 3)
Turn-On Time into 1000pF
Turn-Off Time into 1000pF
DATA/CLK Input Low Voltage
DATA/CLK Input High Voltage
V
CC
= 2.7V (From ON to GA, GB = V
CC
+ 1V) (Note 4)
V
CC
= 5.5V (From ON to GA, GB = V
CC
+ 2V) (Note 4)
V
CC
= 2.7V (From OFF to GA, GB = 100mV) (Note 5)
V
CC
= 5.5V (From OFF to GA, GB = 100mV) (Note 5)
V
CC
= 2.7V to 5.5V
V
CC
= 2.7V to 5.5V
1.4
2
U
U
W
W W
U
W
TOP VIEW
8
7
6
5
V
CC
GA
GB
AD1
ORDER PART
NUMBER
LTC1623CS8
LTC1623IS8
S8 PART MARKING
1623
1623I
CLK 2
AD0 3
GND 4
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 110°C/ W
TYP
12
14
17
140
162
MAX
5.5
30
30
30
250
250
7
7
7
2.5
1000
1000
UNITS
V
µA
µA
µA
µA
µA
V
V
V
V
µs
µs
kHz
µs
µs
µs
µs
2.7
4.5
4.5
1.5
4.2
5.4
6.4
2.0
300
300
300
170
180
17
12
0.6
V
V
LTC1623
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
IL
V
IH
V
OL
C
IN
I
IN
AD0 and AD1 Input Low Voltage
AD0 and AD1 Input High Voltage
Data Output Low Voltage
Input Capacitance
(DATA, CLK, AD0, AD1)
Input Leakage Current (DATA, CLK)
Input Leakage Current(AD0, AD1)
SMBus Related Specs (Note 6)
f
SMB
t
SUSTA
t
BUF
t
HDSTA
t
SUSTP
t
HDDAT
t
SUDAT
t
LOW
t
HIGH
t
f
t
r
I
PULLUP
SMBus Operating Frequency
Start Condition Setup Time
Bus Free Time Between Stop and Start
Start Condition Hold Time
Stop Condition Setup Time
Data Hold Time
Data Setup Time
Clock Low Period
Clock High Period
Clock /Data Fall Time
Clock/Data Rise Time
Current Through External Pull-Up
Resistor on DATA Pin
(Data Pull-Down Current Capacity)
V
CC
= 2.7V to 5.5V
100
10
4.7
4.7
4.0
4.0
300
250
4.7
4.0
50
300
1000
350
100
kHz
µs
µs
µs
µs
ns
ns
µs
µs
ns
ns
µA
T
A
= 25°C, V
CC
= 5V unless otherwise specified. C
GA
= 1000pF, C
GB
= 1000pF
MIN
q
q
q
CONDITIONS
V
CC
= 2.7V to 5.5V
V
CC
= 2.7V to 5.5V
V
CC
= 2.7 to 5.5V, I
PULLUP
= 350µA
TYP
MAX
0.2
UNITS
V
V
V
pF
V
CC
– 0.2
0.22
5
±1
±250
0.4
µA
nA
The
q
denotes the specifications which apply over the full operating
temperature range.
Note 1:
Approximately 3% hysteresis is provided to ensure stable
operation and eliminate false triggering by minor V
CC
glitches.
Note 2:
Measured from V
CC
> V
UVLO
to SMBus ready for data input.
Note 3:
The oscillator frequency is not tested directly but is inferred from
turn-on time.
Note 4:
ON is enabled upon receiving the Stop condition from the SMBus
master.
Note 5:
OFF is enabled upon receiving the Stop condition from the SMBus
master.
Note 6:
SMBus timing specs are guaranteed but not tested.
PIN FUNCTIONS
DATA: (Pin 1)
Open-Drain Connected Serial Data Inter-
face. Must be pulled high to V
CC
with external resistor. The
pull-up current must be limited to 350µA.
CLK: (Pin 2)
Serial Clock Interface. Must be pulled high to
V
CC
with external resistor. The pull-up current must be
limited to 350µA.
AD0: (Pin 3)
Lower Three-State Programmable Address
Pin. Must be connected directly to V
CC
, GND, or V
CC
/2
(using two resistors
≤
1M). Do not float this pin.
GND: (Pin 4)
Ground.
AD1: (Pin 5)
Higher Three-State Programmable Address
Pin. Must be connected directly to V
CC
, GND, or V
CC
/2
(using two resistors
≤
1M). Do not float this pin.
GB: (Pin 6)
Gate Drive to External High-Side Switch. Fully
enhanced by internal charge pump. Controlled by 2nd
LSB of command byte.
GA: (Pin 7)
Gate Drive to External High-Side Switch. Fully
enhanced by internal charge pump. Controlled by LSB of
command byte.
V
CC
: (Pin 8)
Input Supply Voltage. Range from 2.7V to
5.5V.
U
U
U
3
LTC1623
TYPICAL PERFORMANCE CHARACTERISTICS
Standby Current
35
30
STANDBY CURRENT (µA)
400
350
V
CC
= 2.7V
SUPPLY CURRENT (µA)
25
20
15
10
5
0
20 40 60
–60 –40 –20 0
TEMPERATURE (°C)
V
CC
= 5V
V
CC
= 2.7V
Supply Current
400
V
CC
= 5V
350
350
400
SUPPLY CURRENT (µA)
300
250
200
150
100
50
0
–60 –40 –20
0
20
40
60
80
100
ONE CHANNEL ON
BOTH CHANNELS ON
SUPPLY CURRENT (µA)
TEMPERATURE (°C)
1623 G03
t
ON
vs Temperature
500
450
400
350
t
OFF
(µs)
t
ON
(µs)
20
18
16
14
12
10
8
6
4
2
300
250
200
150
100
50
0
–60 –40 –20
0
20
40
60
80
100
V
CC
= 2.7V
V
CC
= 5.5V
TEMPERATURE (°C)
1623 G06
4
U W
Supply Current
300
250
200
150
100
50
BOTH CHANNELS ON
ONE CHANNEL ON
0
20
40
60
80
100
80
100
0
–60 –40 –20
TEMPERATURE (°C)
1623 G02
1623 G04
Supply Current
V
CC
= 6V
300
250
200
150
100
50
0
–60 –40 –20
0
20
40
60
80
100
ONE CHANNEL ON
BOTH CHANNELS ON
TEMPERATURE (°C)
1623 G05
t
OFF
vs Temperature
V
CC
= 2.7V
V
CC
= 5.5V
0
–60 –40 –20
0
20
40
60
80
100
TEMPERATURE (°C)
1623 G07
LTC1623
TYPICAL PERFORMANCE CHARACTERISTICS
GA, GB Output Voltage
16
14
OUTPUT VOLTAGE (V)
V
CC
= 5V
12
10
8
6
4
2
0
–60 –40 –20
0
20
40
60
80
100
DATA V
OL
(mV)
TEMPERATURE (°C)
1623 G08
V
GS
vs Temperature
7
6
5
V
CC
= 3.3V
V
gs
(V)
4
V
CC
= 2.7V
3
2
1
0
20 40 60
–60 –40 –20 0
TEMPERATURE (°C)
0.1
V
CC
= 5.5V
GATE CURRENT (µA)
U W
DATA V
OL
vs Temperature
500
450
400
350
300
250
200
150
100
50
0
–60 –40 –20
0
20
40
60
80
100
V
CC
= 5V
I
PULLUP
= 350µA
TEMPERATURE (°C)
1623 G09
Gate Drive Current
100
V
CC
= 6V
10
V
CC
= 3.3V
V
CC
= 2.7V
1
V
CC
= 5V
80
100
0
2
3
4
5
6
1
GATE VOLTAGE ABOVE SUPPLY (V
GS
)
7
1623 G10
1623 G11
5
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