PHILIPS PCA9548ABS

PCA9548A
8-channel I2C-bus switch with reset
Rev. 03 — 7 July 2009
Product data sheet
1. General description
The PCA9548A is an octal bidirectional translating switch controlled via the I2C-bus. The
SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual
SCx/SDx channel or combination of channels can be selected, determined by the
contents of the programmable control register.
An active LOW reset input allows the PCA9548A to recover from a situation where one of
the downstream I2C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets the
I2C-bus state machine and causes all the channels to be deselected as does the internal
Power-on reset function.
The pass gates of the switches are constructed such that the VDD pin can be used to limit
the maximum high voltage which will be passed by the PCA9548A. This allows the use of
different bus voltages on each pair, so that 1.8 V or 2.5 V or 3.3 V parts can communicate
with 5 V parts without any additional protection. External pull-up resistors pull the bus up
to the desired voltage level for each channel. All I/O pins are 5 V tolerant.
2. Features
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
1-of-8 bidirectional translating switches
I2C-bus interface logic; compatible with SMBus standards
Active LOW reset input
3 address pins allowing up to 8 devices on the I2C-bus
Channel selection via I2C-bus, in any combination
Power-up with all switch channels deselected
Low Ron switches
Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses
No glitch on power-up
Supports hot insertion
Low standby current
Operating power supply voltage range of 2.3 V to 5.5 V
5 V tolerant inputs
0 Hz to 400 kHz clock frequency
ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per
JESD22-A115, and 1000 V CDM per JESD22-C101
n Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
n Three packages offered: SO24, TSSOP24, and HVQFN24
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
3. Ordering information
Table 1.
Ordering information
Type number
Package
Name
Description
Version
PCA9548ABS
HVQFN24
plastic thermal enhanced very thin quad flat package; SOT616-1
no leads; 24 terminals; body 4 × 4 × 0.85 mm
PCA9548AD
SO24
plastic small outline package; 24 leads;
body width 7.5 mm
SOT137-1
PCA9548APW
TSSOP24
plastic thin shrink small outline package; 24 leads;
body width 4.4 mm
SOT355-1
3.1 Ordering options
Table 2.
Ordering options
Type number
Topside mark
Temperature range
PCA9548ABS
548A
−40 °C to +85 °C
PCA9548AD
PCA9548AD
−40 °C to +85 °C
PCA9548APW
PCA9548A
−40 °C to +85 °C
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
2 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
4. Block diagram
PCA9548A
SC0
SC1
SC2
SC3
SC4
SC5
SC6
SC7
SD0
SD1
SD2
SD3
SD4
SD5
SD6
SD7
VSS
VDD
RESET
SCL
SDA
SWITCH CONTROL LOGIC
RESET
CIRCUIT
INPUT
FILTER
A0
I2C-BUS
CONTROL
A1
A2
002aab202
Fig 1.
Block diagram of PCA9548A
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
3 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
5. Pinning information
5.1 Pinning
A0
1
24 VDD
A0
1
A1
2
23 SDA
A1
2
24 VDD
23 SDA
RESET
3
22 SCL
RESET
3
22 SCL
SD0
4
21 A2
SD0
4
21 A2
SC0
5
20 SC7
SC0
5
20 SC7
SD1
6
19 SD7
SD1
6
SC1
7
18 SC6
SC1
7
SD2
8
17 SD6
SD2
8
17 SD6
SC2
9
16 SC5
SC2
9
16 SC5
SD3 10
15 SD5
SD3 10
15 SD5
SC3 11
14 SC4
SC3 11
14 SC4
VSS 12
13 SD4
VSS 12
13 SD4
PCA9548AD
PCA9548APW
002aab199
18 SC6
002aab200
Pin configuration for TSSOP24
19 SCL
20 SDA
21 VDD
22 A0
terminal 1
index area
23 A1
Fig 3.
24 RESET
Pin configuration for SO24
SD0
1
18 A2
SC0
2
17 SC7
SD1
3
SC1
4
SD2
5
14 SD6
SC2
6
13 SC5
16 SD7
15 SC6
SD5 12
9
VSS
SC4 11
8
SD4 10
7
SC3
PCA9548ABS
SD3
Fig 2.
19 SD7
002aab201
Transparent top view
Fig 4.
Pin configuration for HVQFN24 (transparent top view)
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
4 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
5.2 Pin description
Table 3.
Symbol
Pin description
Pin
Description
SO24, TSSOP24
HVQFN24
A0
1
22
address input 0
A1
2
23
address input 1
RESET
3
24
active LOW reset input
SD0
4
1
serial data 0
SC0
5
2
serial clock 0
SD1
6
3
serial data 1
SC1
7
4
serial clock 1
SD2
8
5
serial data 2
SC2
9
6
serial clock 2
SD3
10
7
serial data 3
SC3
11
8
serial clock 3
VSS
12
9[1]
supply ground
SD4
13
10
serial data 4
SC4
14
11
serial clock 4
SD5
15
12
serial data 5
SC5
16
13
serial clock 5
SD6
17
14
serial data 6
SC6
18
15
serial clock 6
SD7
19
16
serial data 7
SC7
20
17
serial clock 7
A2
21
18
address input 2
SCL
22
19
serial clock line
SDA
23
20
serial data line
VDD
24
21
supply voltage
[1]
HVQFN24 package die supply ground is connected to both the VSS pin and the exposed center pad. The
VSS pin must be connected to supply ground for proper device operation. For enhanced thermal, electrical,
and board-level performance, the exposed pad needs to be soldered to the board using a corresponding
thermal pad on the board, and for proper heat conduction through the board thermal vias need to be
incorporated in the PCB in the thermal pad region.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
5 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
6. Functional description
Refer to Figure 1 “Block diagram of PCA9548A”.
6.1 Device address
Following a START condition, the bus master must output the address of the slave it is
accessing. The address of the PCA9548A is shown in Figure 5. To conserve power, no
internal pull-up resistors are incorporated on the hardware selectable address pins and
they must be pulled HIGH or LOW.
1
1
1
0
A2
fixed
A1
A0 R/W
hardware
selectable
002aab189
Fig 5.
Slave address
The last bit of the slave address defines the operation to be performed. When set to
logic 1 a read is selected, while a logic 0 selects a write operation.
6.2 Control register
Following the successful acknowledgement of the slave address, the bus master will send
a byte to the PCA9548A, which will be stored in the control register. If multiple bytes are
received by the PCA9548A, it will save the last byte received. This register can be written
and read via the I2C-bus.
channel selection bits
(read/write)
7
6
5
4
3
2
1
0
B7
B6
B5
B4
B3
B2
B1
B0
channel 0
channel 1
channel 2
channel 3
channel 4
channel 5
channel 6
channel 7
002aab204
Fig 6.
Control register
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
6 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
6.2.1 Control register definition
One or several SCx/SDx downstream pair, or channel, is selected by the contents of the
control register. This register is written after the PCA9548A has been addressed. The
2 LSBs of the control byte are used to determine which channel is to be selected. When a
channel is selected, the channel will become active after a STOP condition has been
placed on the I2C-bus. This ensures that all SCx/SDx lines will be in a HIGH state when
the channel is made active, so that no false conditions are generated at the time of
connection.
Table 4.
Control register: Write—channel selection; Read—channel status
B7
B6
B5
B4
B3
B2
B1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
0
1
X
0
0
1
B0
Command
0
channel 0 disabled
1
channel 0 enabled
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
0
1
0
1
1
channel 1 disabled
channel 1 enabled
channel 2 disabled
channel 2 enabled
channel 3 disabled
channel 3 enabled
channel 4 disabled
channel 4 enabled
channel 5 disabled
channel 5 enabled
channel 6 disabled
channel 6 enabled
channel 7 disabled
channel 7 enabled
Remark: Multiple channels can be enabled at the same time. Example: B7 = 0, B6 = 1,
B5 = 0, B4 = 0, B3 = 1, B2 = 1, B1 = 0, B0 = 0, means that channels 7, 5, 4, 1 and 0 are
disabled and channels 6, 3, and 2 are enabled. Care should be taken not to exceed the
maximum bus capacitance. Default condition is all zeroes.
6.3 RESET input
The RESET input is an active LOW signal which may be used to recover from a bus fault
condition. By asserting this signal LOW for a minimum of tw(rst)L, the PCA9548A will reset
its register and I2C-bus state machine and will deselect all channels. The RESET input
must be connected to VDD through a pull-up resistor.
6.4 Power-on reset
When power is applied to VDD, an internal Power-On Reset (POR) holds the PCA9548A in
a reset condition until VDD has reached VPOR. At this point, the reset condition is released
and the PCA9548A register and I2C-bus state machine are initialized to their default
states (all zeroes) causing all the channels to be deselected. Thereafter, VDD must be
lowered below 0.2 V to reset the device.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
7 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
6.5 Voltage translation
The pass gate transistors of the PCA9548A are constructed such that the VDD voltage can
be used to limit the maximum voltage that will be passed from one I2C-bus to another.
002aaa964
5.0
Vo(sw)
(V)
4.0
(1)
(2)
3.0
(3)
2.0
1.0
2.0
2.5
3.0
3.5
4.0
4.5
5.5
5.0
VDD (V)
(1) maximum
(2) typical
(3) minimum
Fig 7.
Pass gate voltage versus supply voltage
Figure 7 shows the voltage characteristics of the pass gate transistors (note that the
PCA9548A is only tested at the points specified in Section 10 “Static characteristics” of
this data sheet). In order for the PCA9548A to act as a voltage translator, the Vo(sw)
voltage should be equal to, or lower than the lowest bus voltage. For example, if the main
bus was running at 5 V, and the downstream buses were 3.3 V and 2.7 V, then Vo(sw)
should be equal to or below 2.7 V to effectively clamp the downstream bus voltages.
Looking at Figure 7, we see that Vo(sw)(max) will be at 2.7 V when the PCA9548A supply
voltage is 3.5 V or lower, so the PCA9548A supply voltage could be set to 3.3 V. Pull-up
resistors can then be used to bring the bus voltages to their appropriate levels (see
Figure 14).
More Information can be found in Application Note AN262: PCA954X family of I2C/SMBus
multiplexers and switches.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
8 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
7. Characteristics of the I2C-bus
The I2C-bus is for 2-way, 2-line communication between different ICs or modules. The two
lines are a serial data line (SDA) and a serial clock line (SCL). Both lines must be
connected to a positive supply via a pull-up resistor when connected to the output stages
of a device. Data transfer may be initiated only when the bus is not busy.
7.1 Bit transfer
One data bit is transferred during each clock pulse. The data on the SDA line must remain
stable during the HIGH period of the clock pulse as changes in the data line at this time
will be interpreted as control signals (see Figure 8).
SDA
SCL
data line
stable;
data valid
Fig 8.
change
of data
allowed
mba607
Bit transfer
7.2 START and STOP conditions
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW
transition of the data line while the clock is HIGH is defined as the START condition (S). A
LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP
condition (P) (see Figure 9).
SDA
SCL
S
P
START condition
STOP condition
mba608
Fig 9.
Definition of START and STOP conditions
7.3 System configuration
A device generating a message is a ‘transmitter’, a device receiving is the ‘receiver’. The
device that controls the message is the ‘master’ and the devices which are controlled by
the master are the ‘slaves’ (see Figure 10).
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
9 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
SDA
SCL
MASTER
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
I2C-BUS
MULTIPLEXER
SLAVE
002aaa966
Fig 10. System configuration
7.4 Acknowledge
The number of data bytes transferred between the START and the STOP conditions from
transmitter to receiver is not limited. Each byte of eight bits is followed by one
acknowledge bit. The acknowledge bit is a HIGH level put on the bus by the transmitter,
whereas the master generates an extra acknowledge related clock pulse.
A slave receiver which is addressed must generate an acknowledge after the reception of
each byte. Also, a master must generate an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter. The device that acknowledges has to
pull down the SDA line during the acknowledge clock pulse so that the SDA line is stable
LOW during the HIGH period of the acknowledge related clock pulse; set-up and hold
times must be taken into account.
A master receiver must signal an end of data to the transmitter by not generating an
acknowledge on the last byte that has been clocked out of the slave. In this event, the
transmitter must leave the data line HIGH to enable the master to generate a STOP
condition.
data output
by transmitter
not acknowledge
data output
by receiver
acknowledge
SCL from master
1
S
START
condition
2
8
9
clock pulse for
acknowledgement
002aaa987
Fig 11. Acknowledgement on the I2C-bus
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
10 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
7.5 Bus transactions
Data is transmitted to the PCA9548A control register using the Write mode as shown in
Figure 12.
slave address
SDA
S
1
1
1
0
A2
control register
A1
A0
START condition
0
R/W
A
B7
B6
B5
B4
B3
B2
acknowledge
from slave
B1
B0
A
P
acknowledge
from slave
STOP condition
002aab205
Fig 12. Write control register
Data is read from PCA9548A using the Read mode as shown in Figure 13.
slave address
SDA
S
1
1
1
0
A2
START condition
last byte
control register
A1
A0
1
R/W
A
B7
B6
acknowledge
from slave
B5
B4
B3
B2
B1
B0
NA
P
no acknowledge
from master
STOP condition
002aab206
Fig 13. Read control register
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
11 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
8. Application design-in information
VDD = 2.7 V to 5.5 V
VDD = 3.3 V
V = 2.7 V to 5.5 V
SDA
SDA
SD0
SCL
SCL
SC0
channel 0
V = 2.7 V to 5.5 V
RESET
I2C/SMBus master
SD1
channel 1
SC1
V = 2.7 V to 5.5 V
SD2
channel 2
SC2
V = 2.7 V to 5.5 V
SD3
channel 3
SC3
PCA9548A
SD4
V = 2.7 V to 5.5 V
channel 4
SC4
V = 2.7 V to 5.5 V
SD5
channel 5
SC5
V = 2.7 V to 5.5 V
SD6
channel 6
SC6
V = 2.7 V to 5.5 V
A2
A1
A0
SD7
VSS
SC7
channel 7
002aab203
Fig 14. Typical application
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
12 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
9. Limiting values
Table 5.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134). Voltages are referenced to
VSS (ground = 0 V).[1]
Symbol
Parameter
Conditions
Max
Unit
VDD
supply voltage
−0.5
+7.0
V
VI
input voltage
−0.5
+7.0
V
II
input current
-
±20
mA
IO
output current
-
±25
mA
IDD
supply current
-
±100
mA
ISS
ground supply current
-
±100
mA
Ptot
total power dissipation
-
400
mW
Tstg
storage temperature
−60
+150
°C
Tamb
ambient temperature
−40
+85
°C
[1]
operating
The performance capability of a high-performance integrated circuit in conjunction with its thermal
environment can create junction temperatures which are detrimental to reliability. The maximum junction
temperature of this integrated circuit should not exceed 125 °C.
PCA9548A_3
Product data sheet
Min
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
13 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
10. Static characteristics
Table 6.
Static characteristics at VDD = 2.3 V to 3.6 V
VSS = 0 V; Tamb = –40 °C to +85 °C; unless otherwise specified. See Table 7 on page 15 for VDD = 4.5 V to 5.5 V.[1]
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Supply
VDD
supply voltage
2.3
-
3.6
V
IDD
supply current
operating mode; VDD = 3.6 V; no load;
VI = VDD or VSS; fSCL = 100 kHz
-
30
50
µA
Istb
standby current
standby mode; VDD = 3.6 V; no load;
VI = VDD or VSS
-
0.1
1
µA
VPOR
power-on reset voltage
no load; VI = VDD or VSS
-
1.6
2.1
V
−0.5
-
+0.3VDD
V
[2]
Input SCL; input/output SDA
VIL
LOW-level input voltage
VIH
HIGH-level input voltage
IOL
LOW-level output current
0.7VDD
-
6
V
VOL = 0.4 V
3
6
-
mA
VOL = 0.6 V
6
9
-
mA
IL
leakage current
VI = VDD or VSS
−1
-
+1
µA
Ci
input capacitance
VI = VSS
-
15
21
pF
Select inputs A0 to A2, RESET
VIL
LOW-level input voltage
−0.5
-
+0.3VDD
V
VIH
HIGH-level input voltage
0.7VDD
-
VDD + 0.5
V
ILI
input leakage current
pin at VDD or VSS
−1
-
+1
µA
Ci
input capacitance
VI = VSS
-
2
5
pF
ON-state resistance
VDD = 3.0 V to 3.6 V; VO = 0.4 V;
IO = 15 mA
5
11
30
Ω
VDD = 2.3 V to 2.7 V; VO = 0.4 V;
IO = 10 mA
7
16
55
Ω
Vi(sw) = VDD = 3.3 V; Io(sw) = −100 µA
-
1.9
-
V
Vi(sw) = VDD = 3.0 V to 3.6 V;
Io(sw) = −100 µA
1.6
-
2.8
V
Vi(sw) = VDD = 2.5 V; Io(sw) = −100 µA
-
1.5
-
V
Vi(sw) = VDD = 2.3 V to 2.7 V;
Io(sw) = −100 µA
1.1
-
2.0
V
Pass gate
Ron
Vo(sw)
switch output voltage
IL
leakage current
VI = VDD or VSS
−1
-
+1
µA
Cio
input/output capacitance
VI = VSS
-
3
5
pF
[1]
For operation between published voltage ranges, refer to the worst-case parameter in both ranges.
[2]
VDD must be lowered to 0.2 V in order to reset part.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
14 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
Table 7.
Static characteristics at VDD = 4.5 V to 5.5 V
VSS = 0 V; Tamb = −40 °C to +85 °C; unless otherwise specified. See Table 6 on page 14 for VDD = 2.3 V to 3.6 V.[1]
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
4.5
-
5.5
V
Supply
VDD
supply voltage
IDD
supply current
operating mode; VDD = 5.5 V;
no load; VI = VDD or VSS;
fSCL = 100 kHz
-
65
100
µA
Istb
standby current
standby mode; VDD = 5.5 V;
no load; VI = VDD or VSS
-
0.2
1
µA
VPOR
power-on reset voltage
no load; VI = VDD or VSS
-
1.7
2.1
V
[2]
Input SCL; input/output SDA
VIL
LOW-level input voltage
−0.5
-
+0.3VDD
V
VIH
HIGH-level input voltage
0.7VDD
-
6
V
IOL
LOW-level output current
VOL = 0.4 V
3
-
-
mA
VOL = 0.6 V
6
-
-
mA
IIL
LOW-level input current
VI = VSS
−1
-
+1
µA
IIH
HIGH-level input current
VI = VDD
−1
-
+1
µA
Ci
input capacitance
VI = VSS
-
15
21
pF
Select inputs A0 to A2, RESET
VIL
LOW-level input voltage
−0.5
-
+0.3VDD
V
VIH
HIGH-level input voltage
0.7VDD
-
VDD + 0.5
V
ILI
input leakage current
pin at VDD or VSS
−1
-
+1
µA
Ci
input capacitance
VI = VSS
-
2
5
pF
Ron
ON-state resistance
VDD = 4.5 V to 5.5 V; VO = 0.4 V;
IO = 15 mA
4
9
24
Ω
Vo(sw)
switch output voltage
Vi(sw) = VDD = 5.0 V;
Io(sw) = −100 µA
-
3.6
-
V
Vi(sw) = VDD = 4.5 V to 5.5 V;
Io(sw) = −100 µA
2.6
-
4.5
V
Pass gate
IL
leakage current
VI = VDD or VSS
−1
-
+1
µA
Cio
input/output capacitance
VI = VSS
-
3
5
pF
[1]
For operation between published voltage ranges, refer to the worst-case parameter in both ranges.
[2]
VDD must be lowered to 0.2 V in order to reset part.
PCA9548A_3
Product data sheet
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PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
11. Dynamic characteristics
Table 8.
Dynamic characteristics
Symbol
Parameter
Conditions
Standard-mode
I2C-bus
from SDA to SDx,
or SCL to SCx
Fast-mode I2C-bus
Unit
Min
Max
Min
Max
-
0.3[1]
-
0.3[1]
ns
0
100
0
400
kHz
4.7
-
1.3
-
µs
4.0
-
0.6
-
µs
tPD
propagation delay
fSCL
SCL clock frequency
tBUF
bus free time between a STOP and
START condition
tHD;STA
hold time (repeated) START condition
tLOW
LOW period of the SCL clock
4.7
-
1.3
-
µs
tHIGH
HIGH period of the SCL clock
4.0
-
0.6
-
µs
tSU;STA
set-up time for a repeated START
condition
4.7
-
0.6
-
µs
tSU;STO
set-up time for STOP condition
4.0
-
0.6
-
µs
tHD;DAT
data hold time
0[3]
3.45
0[3]
0.9
µs
tSU;DAT
data set-up time
250
-
100
-
ns
tr
rise time of both SDA and SCL signals
-
1000
20 + 0.1Cb[4]
300
ns
tf
fall time of both SDA and SCL signals
-
300
20 + 0.1Cb[4]
300
ns
Cb
capacitive load for each bus line
-
400
-
400
pF
tSP
pulse width of spikes that must be
suppressed by the input filter
-
50
-
50
ns
tVD;DAT
data valid time
[2]
HIGH-to-LOW
[5]
-
1
-
1
µs
LOW-to-HIGH
[5]
-
0.6
-
0.6
µs
data valid acknowledge time
-
1
-
1
µs
tw(rst)L
LOW-level reset time
4
-
4
-
ns
trst
reset time
500
-
500
-
ns
tREC;STA
recovery time to START condition
0
-
0
-
ns
tVD;ACK
RESET
SDA clear
[1]
Pass gate propagation delay is calculated from the 20 Ω typical Ron and the 15 pF load capacitance.
[2]
After this period, the first clock pulse is generated.
[3]
A device must internally provide a hold time of at least 300 ns for the SDA signal (referred to the VIH(min) of the SCL signal) in order to
bridge the undefined region of the falling edge of SCL.
[4]
Cb = total capacitance of one bus line in pF.
[5]
Measurements taken with 1 kΩ pull-up resistor and 50 pF load.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
16 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
SDA
tr
tBUF
tf
tHD;STA
tSP
tLOW
SCL
tHD;STA
P
tSU;STA
tHD;DAT
S
tHIGH
tSU;DAT
tSU;STO
Sr
P
002aaa986
Fig 15. Definition of timing on the I2C-bus
ACK or read cycle
START
SCL
SDA
30 %
trst
RESET
50 %
50 %
50 %
tREC;STA
tw(rst)L
002aac549
Fig 16. Definition of RESET timing
protocol
START
condition
(S)
tSU;STA
bit 7
MSB
(A7)
tLOW
bit 6
(A6)
tHIGH
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
1/f
SCL
SCL
tBUF
tr
tf
SDA
tHD;STA
tSU;DAT
tHD;DAT
tVD;DAT
tVD;ACK
tSU;STO
002aab175
Fig 17. I2C-bus timing diagram
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
17 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
12. Package outline
SO24: plastic small outline package; 24 leads; body width 7.5 mm
SOT137-1
D
E
A
X
c
HE
y
v M A
Z
24
13
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
L
1
12
e
detail X
w M
bp
0
5
10 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (1)
e
HE
L
Lp
Q
v
w
y
mm
2.65
0.3
0.1
2.45
2.25
0.25
0.49
0.36
0.32
0.23
15.6
15.2
7.6
7.4
1.27
10.65
10.00
1.4
1.1
0.4
1.1
1.0
0.25
0.25
0.1
0.01
0.019 0.013
0.014 0.009
0.61
0.60
0.30
0.29
0.05
0.419
0.043
0.055
0.394
0.016
inches
0.1
0.012 0.096
0.004 0.089
0.043
0.039
0.01
0.01
Z
(1)
0.9
0.4
0.035
0.004
0.016
θ
o
8
o
0
Note
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT137-1
075E05
MS-013
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-19
Fig 18. Package outline SOT137-1 (SO24)
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
18 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
TSSOP24: plastic thin shrink small outline package; 24 leads; body width 4.4 mm
D
SOT355-1
E
A
X
c
HE
y
v M A
Z
13
24
Q
A2
(A 3)
A1
pin 1 index
A
θ
Lp
L
1
12
detail X
w M
bp
e
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (2)
e
HE
L
Lp
Q
v
w
y
Z (1)
θ
mm
1.1
0.15
0.05
0.95
0.80
0.25
0.30
0.19
0.2
0.1
7.9
7.7
4.5
4.3
0.65
6.6
6.2
1
0.75
0.50
0.4
0.3
0.2
0.13
0.1
0.5
0.2
8o
0o
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic interlead protrusions of 0.25 mm maximum per side are not included.
OUTLINE
VERSION
SOT355-1
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-19
MO-153
Fig 19. Package outline SOT355-1 (TSSOP24)
PCA9548A_3
Product data sheet
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Rev. 03 — 7 July 2009
19 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
HVQFN24: plastic thermal enhanced very thin quad flat package; no leads;
24 terminals; body 4 x 4 x 0.85 mm
A
B
D
SOT616-1
terminal 1
index area
A
A1
E
c
detail X
e1
C
1/2 e
e
12
y
y1 C
v M C A B
w M C
b
7
L
13
6
e
e2
Eh
1/2 e
1
18
terminal 1
index area
24
19
X
Dh
0
2.5
5 mm
scale
DIMENSIONS (mm are the original dimensions)
UNIT
A(1)
max.
A1
b
c
D (1)
Dh
E (1)
Eh
e
e1
e2
L
v
w
y
y1
mm
1
0.05
0.00
0.30
0.18
0.2
4.1
3.9
2.25
1.95
4.1
3.9
2.25
1.95
0.5
2.5
2.5
0.5
0.3
0.1
0.05
0.05
0.1
Note
1. Plastic or metal protrusions of 0.075 mm maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
JEITA
SOT616-1
---
MO-220
---
EUROPEAN
PROJECTION
ISSUE DATE
01-08-08
02-10-22
Fig 20. Package outline SOT616-1 (HVQFN24)
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
20 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
13. Soldering of SMD packages
This text provides a very brief insight into a complex technology. A more in-depth account
of soldering ICs can be found in Application Note AN10365 “Surface mount reflow
soldering description”.
13.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to
Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both
the mechanical and the electrical connection. There is no single soldering method that is
ideal for all IC packages. Wave soldering is often preferred when through-hole and
Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not
suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high
densities that come with increased miniaturization.
13.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from
a standing wave of liquid solder. The wave soldering process is suitable for the following:
• Through-hole components
• Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless
packages which have solder lands underneath the body, cannot be wave soldered. Also,
leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered,
due to an increased probability of bridging.
The reflow soldering process involves applying solder paste to a board, followed by
component placement and exposure to a temperature profile. Leaded packages,
packages with solder balls, and leadless packages are all reflow solderable.
Key characteristics in both wave and reflow soldering are:
•
•
•
•
•
•
Board specifications, including the board finish, solder masks and vias
Package footprints, including solder thieves and orientation
The moisture sensitivity level of the packages
Package placement
Inspection and repair
Lead-free soldering versus SnPb soldering
13.3 Wave soldering
Key characteristics in wave soldering are:
• Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are
exposed to the wave
• Solder bath specifications, including temperature and impurities
PCA9548A_3
Product data sheet
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Rev. 03 — 7 July 2009
21 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
13.4 Reflow soldering
Key characteristics in reflow soldering are:
• Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 21) than a SnPb process, thus
reducing the process window
• Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
• Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak
temperature is high enough for the solder to make reliable solder joints (a solder paste
characteristic). In addition, the peak temperature must be low enough that the
packages and/or boards are not damaged. The peak temperature of the package
depends on package thickness and volume and is classified in accordance with
Table 9 and 10
Table 9.
SnPb eutectic process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
≥ 350
< 2.5
235
220
≥ 2.5
220
220
Table 10.
Lead-free process (from J-STD-020C)
Package thickness (mm)
Package reflow temperature (°C)
Volume (mm3)
< 350
350 to 2000
> 2000
< 1.6
260
260
260
1.6 to 2.5
260
250
245
> 2.5
250
245
245
Moisture sensitivity precautions, as indicated on the packing, must be respected at all
times.
Studies have shown that small packages reach higher temperatures during reflow
soldering, see Figure 21.
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
22 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 21. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365
“Surface mount reflow soldering description”.
14. Abbreviations
Table 11.
Abbreviations
Acronym
Description
CDM
Charged Device Model
ESD
ElectroStatic Discharge
HBM
Human Body Model
IC
Integrated Circuit
I2C-bus
Inter-Integrated Circuit bus
I/O
Input/Output
LSB
Least Significant Bit
MM
Machine Model
MSB
Most Significant Bit
PCB
Printed-Circuit Board
POR
Power-On Reset
SMBus
System Management Bus
PCA9548A_3
Product data sheet
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Rev. 03 — 7 July 2009
23 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
15. Revision history
Table 12.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
PCA9548_3
20090707
Product data sheet
-
PCA9548A_2
Modifications:
•
The format of this data sheet has been redesigned to comply with the new identity guidelines
of NXP Semiconductors.
•
•
Legal texts have been adapted to the new company name where appropriate.
Table 8 “Dynamic characteristics”:
– Symbol tf: changed Unit from “µs” to “ns”
– Symbol Cb: changed Unit from “µs” to “pF”
•
Updated soldering information.
PCA9548_2
(9397 750 14726)
20060925
Product data sheet
-
PCA9548A_1
PCA9548A_1
(9397 750 13297)
20050415
Product data sheet
-
-
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
24 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
16. Legal information
16.1 Data sheet status
Document status[1][2]
Product status[3]
Definition
Objective [short] data sheet
Development
This document contains data from the objective specification for product development.
Preliminary [short] data sheet
Qualification
This document contains data from the preliminary specification.
Product [short] data sheet
Production
This document contains the product specification.
[1]
Please consult the most recently issued document before initiating or completing a design.
[2]
The term ‘short data sheet’ is explained in section “Definitions”.
[3]
The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status
information is available on the Internet at URL http://www.nxp.com.
16.2 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences of
use of such information.
Short data sheet — A short data sheet is an extract from a full data sheet
with the same product type number(s) and title. A short data sheet is intended
for quick reference only and should not be relied upon to contain detailed and
full information. For detailed and full information see the relevant full data
sheet, which is available on request via the local NXP Semiconductors sales
office. In case of any inconsistency or conflict with the short data sheet, the
full data sheet shall prevail.
16.3 Disclaimers
General — Information in this document is believed to be accurate and
reliable. However, NXP Semiconductors does not give any representations or
warranties, expressed or implied, as to the accuracy or completeness of such
information and shall have no liability for the consequences of use of such
information.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
malfunction of an NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is at the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) may cause permanent
damage to the device. Limiting values are stress ratings only and operation of
the device at these or any other conditions above those given in the
Characteristics sections of this document is not implied. Exposure to limiting
values for extended periods may affect device reliability.
Terms and conditions of sale — NXP Semiconductors products are sold
subject to the general terms and conditions of commercial sale, as published
at http://www.nxp.com/profile/terms, including those pertaining to warranty,
intellectual property rights infringement and limitation of liability, unless
explicitly otherwise agreed to in writing by NXP Semiconductors. In case of
any inconsistency or conflict between information in this document and such
terms and conditions, the latter will prevail.
No offer to sell or license — Nothing in this document may be interpreted
or construed as an offer to sell products that is open for acceptance or the
grant, conveyance or implication of any license under any copyrights, patents
or other industrial or intellectual property rights.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a prior
authorization from national authorities.
16.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks
are the property of their respective owners.
I2C-bus — logo is a trademark of NXP B.V.
17. Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
PCA9548A_3
Product data sheet
© NXP B.V. 2009. All rights reserved.
Rev. 03 — 7 July 2009
25 of 26
PCA9548A
NXP Semiconductors
8-channel I2C-bus switch with reset
18. Contents
1
2
3
3.1
4
5
5.1
5.2
6
6.1
6.2
6.2.1
6.3
6.4
6.5
7
7.1
7.2
7.3
7.4
7.5
8
9
10
11
12
13
13.1
13.2
13.3
13.4
14
15
16
16.1
16.2
16.3
16.4
17
18
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Ordering options . . . . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 5
Functional description . . . . . . . . . . . . . . . . . . . 6
Device address . . . . . . . . . . . . . . . . . . . . . . . . . 6
Control register . . . . . . . . . . . . . . . . . . . . . . . . . 6
Control register definition . . . . . . . . . . . . . . . . . 7
RESET input . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . 7
Voltage translation . . . . . . . . . . . . . . . . . . . . . . 8
Characteristics of the I2C-bus. . . . . . . . . . . . . . 9
Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
START and STOP conditions . . . . . . . . . . . . . . 9
System configuration . . . . . . . . . . . . . . . . . . . . 9
Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . 10
Bus transactions . . . . . . . . . . . . . . . . . . . . . . . 11
Application design-in information . . . . . . . . . 12
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 13
Static characteristics. . . . . . . . . . . . . . . . . . . . 14
Dynamic characteristics . . . . . . . . . . . . . . . . . 16
Package outline . . . . . . . . . . . . . . . . . . . . . . . . 18
Soldering of SMD packages . . . . . . . . . . . . . . 21
Introduction to soldering . . . . . . . . . . . . . . . . . 21
Wave and reflow soldering . . . . . . . . . . . . . . . 21
Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 21
Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 22
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Revision history . . . . . . . . . . . . . . . . . . . . . . . . 24
Legal information. . . . . . . . . . . . . . . . . . . . . . . 25
Data sheet status . . . . . . . . . . . . . . . . . . . . . . 25
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Contact information. . . . . . . . . . . . . . . . . . . . . 25
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in section ‘Legal information’.
© NXP B.V. 2009.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
Date of release: 7 July 2009
Document identifier: PCA9548A_3