PCA9545APW,112 - NXP Semiconductors / Philips Semiconductors

1. General description

The PCA9545A/45B/45C is a quad bidirectional translating switch controlled via the

I2C-bus. The SCL/SDA upstream pair fans out to four 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. Four interrupt inputs, INT0 to INT3, one

for each of the downstream pairs, are provided. One interrupt output, INT, acts as an AND

of the four interrupt inputs.

An active LOW reset input allows the PCA9545A/45B/45C 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 PCA9545A/45B/45C. 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.

The PCA9545A, PCA9545B and PCA9545C are identical except for the ﬁxed portion of

the slave address.

2. Features

n1-of-4 bidirectional translating switches

nI2C-bus interface logic; compatible with SMBus standards

n4 active LOW interrupt inputs

nActive LOW interrupt output

nActive LOW reset input

n2 address pins allowing up to 4 devices on the I2C-bus

nAlternate address versions A, B and C allow up to a total of 12 devices on the bus for

larger systems or to resolve address conﬂicts

nChannel selection via I2C-bus, in any combination

nPower-up with all switch channels deselected

nLow Ron switches

nAllows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses

nNo glitch on power-up

nSupports hot insertion

nLow standby current

nOperating power supply voltage range of 2.3 V to 5.5 V

PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

Rev. 07 — 19 June 2009 Product data sheet

Product data sheet Rev. 07 — 19 June 2009 2 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

n5 V tolerant Inputs

n0 Hz to 400 kHz clock frequency

nESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per

JESD22-A115, and 1000 V CDM per JESD22-C101

nLatch-up protection exceeds 100 mA per JESD78

nThree packages offered: SO20, TSSOP20, and HVQFN20

3. Ordering information

3.1 Ordering options

Table 1. Ordering information

Type number Package

Name Description Version

PCA9545ABS HVQFN20 plastic thermal enhanced very thin quad ﬂat package;

no leads; 20 terminals; body 5 ×5×0.85 mm SOT662-1

PCA9545AD SO20 plastic small outline package; 20 leads;

body width 7.5 mm SOT163-1

PCA9545APW TSSOP20 plastic thin shrink small outline package; 20 leads;

body width 4.4 mm SOT360-1

PCA9545BPW

PCA9545CPW

Table 2. Ordering options

Type number Topside mark Temperature range

PCA9545ABS 9545A −40 °Cto+85°C

PCA9545AD PCA9545AD −40 °Cto+85°C

PCA9545APW PA9545A −40 °Cto+85°C

PCA9545BPW PA9545B −40 °Cto+85°C

PCA9545CPW PA9545C −40 °Cto+85°C

Product data sheet Rev. 07 — 19 June 2009 3 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

4. Block diagram

Fig 1. Block diagram of PCA9545A/45B/45C

SWITCH CONTROL LOGIC

PCA9545A/PCA9545B/PCA9545C

POWER-ON

RESET

002aab168

SC0

SC1

SC2

SC3

SD0

SD1

SD2

SD3

VSS

VDD

RESET

I2C-BUS

CONTROL

INPUT

FILTER

SCL

SDA

INTERRUPT LOGIC

INT0

INT3

INT

Product data sheet Rev. 07 — 19 June 2009 4 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

5. Pinning information

5.1 Pinning

Fig 2. Pin conﬁguration for SO20 Fig 3. Pin conﬁguration for TSSOP20

Fig 4. Pin conﬁguration for HVQFN20 (transparent top view)

PCA9545AD

A0 VDD

A1 SDA

RESET SCL

INT0 INT

SD0 SC3

SC0 SD3

INT1 INT3

SD1 SC2

SC1 SD2

VSS INT2

002aab165

19 VDD

SDA

SCL

INT

SC3

SD3

INT3

SC2

SD2

INT2

RESET

INT0

SD0

SC0

INT1

SD1

SC1

VSS

PCA9545APW

PCA9545BPW

PCA9545CPW

002aab166

VDD

SDA

SCL

INT

SC3

SD3

INT3

SC2

RESET

INT0

SD0

SC0

INT1

SD1

SC1

VSS

002aab167

PCA9545ABS

Transparent top view

5 11

4 12

3 13

2 14

1 15

terminal 1

index area

SD2

INT2

Product data sheet Rev. 07 — 19 June 2009 5 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

5.2 Pin description

[1] HVQFN20 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.

Table 3. Pin description

Symbol Pin Description

SO20, TSSOP20 HVQFN20

A0 1 19 address input 0

A1 2 20 address input 1

RESET 3 1 active LOW reset input

INT0 4 2 active LOW interrupt input 0

SD0 5 3 serial data 0

SC0 6 4 serial clock 0

INT1 7 5 active LOW interrupt input 1

SD1 8 6 serial data 1

SC1 9 7 serial clock 1

VSS 10 8[1] supply ground

INT2 11 9 active LOW interrupt input 2

SD2 12 10 serial data 2

SC2 13 11 serial clock 2

INT3 14 12 active LOW interrupt input 3

SD3 15 13 serial data 3

SC3 16 14 serial clock 3

INT 17 15 active LOW interrupt output

SCL 18 16 serial clock line

SDA 19 17 serial data line

VDD 20 18 supply voltage

Product data sheet Rev. 07 — 19 June 2009 6 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

6. Functional description

Refer to Figure 1 “Block diagram of PCA9545A/45B/45C”.

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 PCA9545A 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.

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.

The PCA9545BPW and PCA9545CPW are alternate address versions if needed for larger

systems or to resolve conﬂicts. The data sheet will reference the PCA9545A, but the

PCA9545B and PCA9545C function identically except for the slave address.

Fig 5. Slave address PCA9545A

Fig 6. Slave address PCA9545B Fig 7. Slave address PCA9545C

002aab169

1 1 1 0 0 A1 A0 R/W

fixed hardware

selectable

002aab835

1 1 0 1 0 A1 A0 R/W

fixed hardware

selectable

002aab836

1 0 1 1 0 A1 A0 R/W

fixed hardware

selectable

Product data sheet Rev. 07 — 19 June 2009 7 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

6.2 Control register

Following the successful acknowledgement of the slave address, the bus master will send

a byte to the PCA9545A/45B/45C, which will be stored in the control register. If multiple

bytes are received by the PCA9545A/45B/45C, it will save the last byte received. This

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 PCA9545A/45B/45C has been

addressed. The 4 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.

Remark: Several channels can be enabled at the same time. Example: B3 = 0, B2 = 1,

B1 = 1, B0 = 0, means that channel 0 and channel 3 are disabled and channel 1 and

channel 2 are enabled. Care should be taken not to exceed the maximum bus capacity.

Fig 8. Control register

002aab170

INT

3INT

2INT

1INT

0B3 B2 B1 B0

channel selection bits

(read/write)

76543210

interrupt bits

(read only)

channel 0

channel 1

channel 2

channel 3

INT0

INT1

INT2

INT3

Table 4. Control register: write (channel selection); read (channel status)

INT3 INT2 INT1 INT0 B3 B2 B1 B0 Command

XXXXXXX0 channel 0 disabled

1 channel 0 enabled

XXXXXX0Xchannel 1 disabled

1 channel 1 enabled

XXXXX0XXchannel 2 disabled

1 channel 2 enabled

XXXX0XXXchannel 3 disabled

1 channel 3 enabled

00000000no channel selected;

power-up/reset default state

Product data sheet Rev. 07 — 19 June 2009 8 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

6.2.2 Interrupt handling

The PCA9545A/45B/45C provides 4 interrupt inputs, one for each channel, and one

open-drain interrupt output. When an interrupt is generated by any device, it will be

detected by the PCA9545A/45B/45C and the interrupt output will be driven LOW. The

channel does not need to be active for detection of the interrupt. A bit is also set in the

control register.

Bit 4 through bit 7 of the control register corresponds to channel 0 through channel 3 of

the PCA9545A/45B/45C, respectively. Therefore, if an interrupt is generated by any

device connected to channel 1, the state of the interrupt inputs is loaded into the control

channel 0 would cause bit 4 of the control register to be set on the read. The master can

then address the PCA9545A/45B/45C and read the contents of the control register to

determine which channel contains the device generating the interrupt. The master can

then reconﬁgure the PCA9545A/45B/45C to select this channel, and locate the device

generating the interrupt and clear it.

It should be noted that more than one device can provide an interrupt on a channel, so it is

up to the master to ensure that all devices on a channel are interrogated for an interrupt.

The interrupt inputs may be used as general purpose inputs if the interrupt function is not

required.

If unused, interrupt input(s) must be connected to VDD through a pull-up resistor.

Remark: Several interrupts can be active at the same time. Example: INT3 = 0, INT2 = 1,

INT1 = 1, INT0 = 0, means that there is no interrupt on channel 0 and channel 3, and

there is interrupt on channel 1 and channel 2.

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 PCA9545A/45B/45C

will reset its registers and I2C-bus state machine and will deselect all channels. The

RESET input must be connected to VDD through a pull-up resistor.

Table 5. Control register: Read—interrupt

INT3 INT2 INT1 INT0 B3 B2 B1 B0 Command

XXX0XXXXno interrupt on channel 0

1 interrupt on channel 0

XX0XXXXXno interrupt on channel 1

1 interrupt on channel 1

X0XXXXXXno interrupt on channel 2

1 interrupt on channel 2

0XXXXXXXno interrupt on channel 3

1 interrupt on channel 3

Product data sheet Rev. 07 — 19 June 2009 9 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

6.4 Power-on reset

When power is applied to VDD, an internal Power-On Reset (POR) holds the

PCA9545A/45B/45C in a reset condition until VDD has reached VPOR. At this point, the

reset condition is released and the PCA9545A/45B/45C registers 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.

6.5 Voltage translation

The pass gate transistors of the PCA9545A/45B/45C 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.

Figure 9 shows the voltage characteristics of the pass gate transistors (note that the graph

was generated using the data speciﬁed in Section 10 “Static characteristics” of this data

sheet). In order for the PCA9545A/45B/45C 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 9, we see that Vo(sw)(max) will be at 2.7 V when the PCA9545A/45B/45C

supply voltageis 3.5 V or lower, so the PCA9545A/45B/45C 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 16).

More Information can be found in Application Note

AN262: PCA954X family of I

C/SMBus

multiplexers and switches

(1) maximum

(2) typical

(3) minimum

Fig 9. Pass gate voltage versus supply voltage

VDD (V)

2.0 5.54.53.0 4.0

002aaa964

3.0

2.0

4.0

5.0

Vo(sw)

(V)

1.0 3.5 5.02.5

(1)

(2)

(3)

Product data sheet Rev. 07 — 19 June 2009 10 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and 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 10).

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 11).

Fig 10. Bit transfer

mba607

data line

stable;

data valid

change

of data

allowed

SDA

SCL

Fig 11. Deﬁnition of START and STOP conditions

mba608

SDA

SCL P

STOP condition

START condition

Product data sheet Rev. 07 — 19 June 2009 11 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

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 12).

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.

Fig 12. System conﬁguration

002aaa966

MASTER

TRANSMITTER/

RECEIVER

SLAVE

RECEIVER SLAVE

TRANSMITTER/

RECEIVER

MASTER

TRANSMITTER MASTER

TRANSMITTER/

RECEIVER

SDA

SCL

I2C-BUS

MULTIPLEXER

SLAVE

Fig 13. Acknowledgement on the I2C-bus

002aaa987

START

condition

9821

clock pulse for

acknowledgement

not acknowledge

acknowledge

data output

by transmitter

data output

by receiver

SCL from master

Product data sheet Rev. 07 — 19 June 2009 12 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

7.5 Bus transactions

Data is transmitted to the PCA9545A/45B/45C control register using the Write mode as

shown in Figure 14.

Data is read from PCA9545A/45B/45C using the Read mode as shown in Figure 15.

Fig 14. Write control register

Fig 15. Read control register

002aab172

XXXXB3B2B1B01 1 0 0 A1 A0 0 AS 1 A P

slave address

START condition R/W acknowledge

from slave acknowledge

from slave

control register

SDA

STOP condition

002aab173

INT3 INT2 INT1 INT0 B3 B2 B1 B01 1 0 0 A1 A0 1 AS 1 NA P

slave address

START condition R/W acknowledge

from slave no acknowledge

from master

control register

SDA

STOP condition

last byte

Product data sheet Rev. 07 — 19 June 2009 13 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

8. Application design-in information

(1) If the device generating the interrupt has an open-drain output structure or can be 3-stated, a

pull-up resistor is required.

If the device generating the interrupt has a totem-pole output structure and cannot be 3-stated, a

pull-up resistor is not required.

The interrupt inputs should not be left ﬂoating.

Fig 16. Typical application

PCA9545A

SD0

SC0

VSS

SDA

SCL

RESET

VDD = 3.3 VVDD = 2.7 V to 5.5 V

I2C-bus/SMBus master

002aab171

SDA

SCL channel 0

V = 2.7 V to 5.5 V

INT INT0

see note (1)

SD1

SC1 channel 1

V = 2.7 V to 5.5 V

INT1

see note (1)

SD2

SC2 channel 2

V = 2.7 V to 5.5 V

INT2

see note (1)

SD3

SC3 channel 3

V = 2.7 V to 5.5 V

INT3

see note (1)

Product data sheet Rev. 07 — 19 June 2009 14 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

9. Limiting values

[1] 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.

Table 6. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134). Voltages are referenced to

(ground=0V).

[1]

Symbol Parameter Conditions Min Max Unit

VDD supply voltage −0.5 +7.0 V

VIinput voltage −0.5 +7.0 V

IIinput current - ±20 mA

IOoutput 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 operating −40 +85 °C

Product data sheet Rev. 07 — 19 June 2009 15 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

10. Static characteristics

[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.

Table 7. Static characteristics at VDD = 2.3 V to 3.6 V

= 0 V; T

amb

−

C to +85

C; unless otherwise speciﬁed. See Table 8 on page 16 for V

= 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 Operatingmode;VDD = 3.6 V;no load;

VI=V

DD or VSS; fSCL = 100 kHz -1030µA

Istb standby current Standby mode; VDD = 3.6 V; no load;

VI=V

DD or VSS

- 0.1 1 µA

VPOR power-on reset voltage no load; VI=V

DD or VSS [2] - 1.6 2.1 V

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 7 - mA

VOL = 0.6 V 6 10 - mA

ILleakage current VI=V

DD or VSS −1-+1 µA

Ciinput capacitance VI=V

SS -1013pF

Select inputs A0, A1, INT0 to INT3, RESET

VIL LOW-level input voltage −0.5 - +0.3VDD V

VIH HIGH-level input voltage 0.7VDD -V

DD + 0.5 V

ILI input leakage current pin at VDD or VSS −1-+1 µA

Ciinput capacitance VI=V

SS - 1.6 3 pF

Pass gate

Ron ON-state resistance VDD = 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=10mA 71655Ω

Vo(sw) switch output voltage Vi(sw) =V

DD = 3.3 V; Io(sw) =−100 µA - 1.9 - V

Vi(sw) =V

DD = 3.0 V to 3.6 V;

Io(sw) =−100 µA1.6 - 2.8 V

Vi(sw) =V

DD = 2.5 V; Io(sw) =−100 µA - 1.5 - V

Vi(sw) =V

DD = 2.3 V to 2.7 V;

Io(sw) =−100 µA1.1 - 2.0 V

ILleakage current VI=V

DD or VSS −1-+1 µA

Cio input/output capacitance VI=V

SS -35 pF

INT output

IOL LOW-level output current VOL = 0.4 V 3 - - mA

IOH HIGH-level output current - - +10 µA

Product data sheet Rev. 07 — 19 June 2009 16 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

[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.

Table 8. Static characteristics at VDD = 4.5 V to 5.5 V

= 0 V; T

amb

−

C to +85

C; unless otherwise speciﬁed. See Table 7 on page 15 for V

= 2.3 V to 3.6 V

[1]

Symbol Parameter Conditions Min Typ Max Unit

Supply

VDD supply voltage 4.5 - 5.5 V

IDD supply current Operating mode; VDD = 5.5 V;

no load; VI=V

DD or VSS;

fSCL = 100 kHz

- 25 100 µA

Istb standby current Standby mode; VDD = 5.5 V;

no load; VI=V

DD or VSS

- 0.3 1 µA

VPOR power-on reset voltage no load; VI=V

DD or VSS [2] - 1.7 2.1 V

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

ILleakage current VI=V

SS −1- +1 µA

Ciinput capacitance VI=V

SS -1013pF

Select inputs A0, A1, INT0 to INT3, RESET

VIL LOW-level input voltage −0.5 - +0.3VDD V

VIH HIGH-level input voltage 0.7VDD -V

DD + 0.5 V

ILI input leakage current VI=V

DD or VSS −1- +1 µA

Ciinput capacitance VI=V

SS -25 pF

Pass gate

Ron ON-state resistance VDD = 4.5 V to 5.5 V; VO= 0.4 V;

IO=15mA 4924Ω

Vo(sw) switch output voltage Vi(sw) =V

DD = 5.0 V;

Io(sw) =−100 µA- 3.6 - V

Vi(sw) =V

DD = 4.5 V to 5.5 V;

Io(sw) =−100 µA2.6 - 4.5 V

ILleakage current VI=V

DD or VSS −1- +1 µA

Cio input/output capacitance VI=V

SS -35 pF

INT output

IOL LOW-level output current VOL = 0.4 V 3 - - mA

IOH HIGH-level output current - - +10 µA

Product data sheet Rev. 07 — 19 June 2009 17 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

11. Dynamic characteristics

[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.

Table 9. Dynamic characteristics

Symbol Parameter Conditions Standard-mode

I2C-bus Fast-mode I2C-bus Unit

Min Max Min Max

tPD propagation delay from SDA to SDx,

or SCL to SCx - 0.3[1] - 0.3[1] ns

fSCL SCL clock frequency 0 100 0 400 kHz

tBUF bus free time between a STOP and

START condition 4.7 - 1.3 - µs

tHD;STA hold time (repeated) START condition [2] 4.0 - 0.6 - µs

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

trrise time of both SDA and SCL

signals - 1000 20 + 0.1Cb[4] 300 ns

tffall time of both SDA and SCL signals - 300 20 + 0.1Cb[4] 300 ns

Cbcapacitive 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 HIGH-to-LOW [5] -1 - 1µs

LOW-to-HIGH [5] - 0.6 - 0.6 µs

tVD;ACK data valid acknowledge time - 1 - 1 µs

INT

tv(INTnN-INTN) valid time from INTn to INT signal - 4 - 4 µs

td(INTnN-INTN) delay time from INTn to INT inactive - 2 - 2 µs

tw(rej)L LOW-level rejection time INTn inputs 1 - 1 - µs

tw(rej)H HIGH-level rejection time INTn inputs 0.5 - 0.5 - µs

RESET

tw(rst)L LOW-level reset time 4 - 4 - ns

trst reset time SDA clear 500 - 500 - ns

tREC;STA recovery time to START condition 0 - 0 - ns

Product data sheet Rev. 07 — 19 June 2009 18 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

Fig 17. Deﬁnition of timing on the I2C-bus

tSP

tBUF

tHD;STA PP S

tLOW

tHD;DAT

tHIGH tSU;DAT tSU;STA

tHD;STA

tSU;STO

SDA

SCL

002aaa986

Fig 18. Deﬁnition of RESET timing

SDA

SCL

002aac549

50 %

30 %

50 % 50 %

tREC;STA tw(rst)L

RESET

START

trst

ACK or read cycle

Rise and fall times refer to VIL and VIH.

Fig 19. I2C-bus timing diagram

SCL

SDA

tHD;STA tSU;DAT tHD;DAT

tBUF

tSU;STA tLOW tHIGH

tVD;ACK

002aab175

tSU;STO

protocol START

condition

(S)

bit 7

MSB

(A7)

bit 6

(A6) bit 0

(R/W) acknowledge

(A)

STOP

condition

(P)

1/fSCL

tVD;DAT

Product data sheet Rev. 07 — 19 June 2009 19 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

12. Test information

Fig 20. Expanded view of read input port register

SCL

002aab176

210AP

70 %

30 %

SDA

INPUT 50 %

INT

tv(INTnN−INTN) td(INTnN−INTN)

Deﬁnitions test circuit:

RL= Load resistance.

CL= Load capacitance including jig and probe capacitance.

RT= Termination resistance should be equal to the output impedance Zo of the pulse generator.

Fig 21. Test circuitry for switching times

PULSE

GENERATOR

50 pF

500 Ω

002aab177

VDD

D.U.T.

Product data sheet Rev. 07 — 19 June 2009 20 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

13. Package outline

Fig 22. Package outline SOT163-1 (SO20)

UNIT A

max. A1A2A3bpcD

(1) E(1) (1)

ELL

pQZ

ywv θ

REFERENCES

OUTLINE

VERSION EUROPEAN

PROJECTION ISSUE DATE

IEC JEDEC JEITA

inches

2.65 0.3

0.1 2.45

2.25 0.49

0.36 0.32

0.23 13.0

12.6 7.6

7.4 1.27 10.65

10.00 1.1

1.0 0.9

0.4 8

0.25 0.1

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

Note

1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.

1.1

0.4

SOT163-1

detail X

0.25

075E04 MS-013

pin 1 index

0.1 0.012

0.004 0.096

0.089 0.019

0.014 0.013

0.009 0.51

0.49 0.30

0.29 0.05

1.4

0.055

0.419

0.394 0.043

0.039 0.035

0.016

0.01

0.25

0.01 0.004

0.043

0.016

0.01

0 5 10 mm

scale

vMA

(A )

SO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1

99-12-27

03-02-19

Product data sheet Rev. 07 — 19 June 2009 21 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

Fig 23. Package outline SOT360-1 (TSSOP20)

UNIT A1A2A3bpcD

(1) E(2) (1)

ELL

pQZywv θ

REFERENCES

OUTLINE

VERSION EUROPEAN

PROJECTION ISSUE DATE

IEC JEDEC JEITA

mm 0.15

0.05 0.95

0.80 0.30

0.19 0.2

0.1 6.6

6.4 4.5

4.3 0.65 6.6

6.2 0.4

0.3 0.5

0.2 8

0.13 0.10.21

DIMENSIONS (mm are the original dimensions)

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.

0.75

0.50

SOT360-1 MO-153 99-12-27

03-02-19

0.25

110

20 11

pin 1 index

detail X

(A )

vMA

0 2.5 5 mm

scale

TSSOP20: plastic thin shrink small outline package; 20 leads; body width 4.4 mm SOT360-1

max.

1.1

Product data sheet Rev. 07 — 19 June 2009 22 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

Fig 24. Package outline SOT662-1 (HVQFN20)

0.651

A1Eh

UNIT ye

0.2

REFERENCES

OUTLINE

VERSION EUROPEAN

PROJECTION ISSUE DATE

IEC JEDEC JEITA

mm 5.1

4.9

3.25

2.95

5.1

4.9 3.25

2.95

2.6

0.38

0.23

0.05

0.00 0.05 0.1

DIMENSIONS (mm are the original dimensions)

SOT662-1 MO-220- - - - - -

0.75

0.50

0.1

0.05

0 2.5 5 mm

scale

SOT662-1

HVQFN20: plastic thermal enhanced very thin quad flat package; no leads;

20 terminals; body 5 x 5 x 0.85 mm

A(1)

max.

AA1c

detail X

y1C

610

20 16

terminal 1

index area

terminal 1

index area

01-08-08

02-10-22

E(1)

D(1)

Note

1. Plastic or metal protrusions of 0.075 mm maximum per side are not included.

Product data sheet Rev. 07 — 19 June 2009 23 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

14. 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”

14.1 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.

14.2 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

14.3 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

Product data sheet Rev. 07 — 19 June 2009 24 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

14.4 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 25) 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 10 and 11

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 25.

Table 10. 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 11. 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

Product data sheet Rev. 07 — 19 June 2009 25 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

For further information on temperature proﬁles, refer to Application Note

AN10365

“Surface mount reﬂow soldering description”

15. Abbreviations

MSL: Moisture Sensitivity Level

Fig 25. Temperature proﬁles for large and small components

001aac844

temperature

time

minimum peak temperature

= minimum soldering temperature

maximum peak temperature

= MSL limit, damage level

peak

temperature

Table 12. Abbreviations

Acronym Description

CDM Charged-Device Model

DUT Device Under Test

ESD ElectroStatic Discharge

HBM Human Body Model

IC Integrated Circuit

I2C-bus Inter-Integrated Circuit bus

LSB Least Signiﬁcant Bit

MM Machine Model

MSB Most Signiﬁcant Bit

PCB Printed-Circuit Board

POR Power-On Reset

SMBus System Management Bus

Product data sheet Rev. 07 — 19 June 2009 26 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

16. Revision history

Table 13. Revision history

Document ID Release date Data sheet status Change notice Supersedes

PCA9545A_45B_45C_7 20090619 Product data sheet - PCA9545A_45B_45C_6

Modiﬁcations: •Table 9 “Dynamic characteristics”:

–Symbol tf: changed Unit from “µs” to “ns”

–Symbol Cb: changed Unit from “µs” to “pF”

•Updated soldering information.

PCA9545A_45B_45C_6 20070319 Product data sheet - PCA9545A_45B_45C_5

PCA9545A_45B_45C_5 20061017 Product data sheet - PCA9545A_4

PCA9545A_4 20060925 Product data sheet - PCA9545A_3

PCA9545A_3

(9397 750 14311) 20050303 Product data sheet - PCA9545A_2

PCA9545A_2

(9397 750 13989) 20040929 Objective data sheet - PCA9545A_1

PCA9545A_1

(9397 750 13309) 20040728 Objective data sheet - -

Product data sheet Rev. 07 — 19 June 2009 27 of 28

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

17. Legal information

17.1 Data sheet status

[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.

17.2 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.

17.3 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.

17.4 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.

18. Contact information

For more information, please visit: http://www.nxp.com

For sales ofﬁce addresses, please send an email to: salesaddresses@nxp.com

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.

NXP Semiconductors PCA9545A/45B/45C

4-channel I2C-bus switch with interrupt logic and reset

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

Date of release: 19 June 2009

Document identifier: PCA9545A_45B_45C_7

Please be aware that important notices concerning this document and the product(s)

described herein, have been included in section ‘Legal information’.

19. Contents

1 General description. . . . . . . . . . . . . . . . . . . . . . 1

2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3 Ordering information. . . . . . . . . . . . . . . . . . . . . 2

3.1 Ordering options. . . . . . . . . . . . . . . . . . . . . . . . 2

4 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5 Pinning information. . . . . . . . . . . . . . . . . . . . . . 4

5.1 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

5.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 5

6 Functional description . . . . . . . . . . . . . . . . . . . 6

6.1 Device address. . . . . . . . . . . . . . . . . . . . . . . . . 6

6.2 Control register. . . . . . . . . . . . . . . . . . . . . . . . . 7

6.2.1 Control register deﬁnition . . . . . . . . . . . . . . . . . 7

6.2.2 Interrupt handling . . . . . . . . . . . . . . . . . . . . . . . 8

6.3 RESET input. . . . . . . . . . . . . . . . . . . . . . . . . . . 8

6.4 Power-on reset . . . . . . . . . . . . . . . . . . . . . . . . . 9

6.5 Voltage translation . . . . . . . . . . . . . . . . . . . . . . 9

7 Characteristics of the I2C-bus. . . . . . . . . . . . . 10

7.1 Bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

7.2 START and STOP conditions . . . . . . . . . . . . . 10

7.3 System conﬁguration . . . . . . . . . . . . . . . . . . . 11

7.4 Acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . 11

7.5 Bus transactions. . . . . . . . . . . . . . . . . . . . . . . 12

8 Application design-in information . . . . . . . . . 13

9 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 14

10 Static characteristics. . . . . . . . . . . . . . . . . . . . 15

11 Dynamic characteristics . . . . . . . . . . . . . . . . . 17

12 Test information. . . . . . . . . . . . . . . . . . . . . . . . 19

13 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 20

14 Soldering of SMD packages . . . . . . . . . . . . . . 23

14.1 Introduction to soldering . . . . . . . . . . . . . . . . . 23

14.2 Wave and reﬂow soldering . . . . . . . . . . . . . . . 23

14.3 Wave soldering. . . . . . . . . . . . . . . . . . . . . . . . 23

14.4 Reﬂow soldering. . . . . . . . . . . . . . . . . . . . . . . 24

15 Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . 25

16 Revision history. . . . . . . . . . . . . . . . . . . . . . . . 26

17 Legal information. . . . . . . . . . . . . . . . . . . . . . . 27

17.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 27

17.2 Deﬁnitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

17.3 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . 27

17.4 Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 27

18 Contact information. . . . . . . . . . . . . . . . . . . . . 27

19 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28