PCA9508
Hot swappable level translating I2C-bus repeater
Rev. 01 — 28 April 2008
Product data sheet
1. General description
The PCA9508 is a CMOS integrated circuit that supports hot-swap with zero offset and
provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to
5.5 V) for I2C-bus or SMBus applications. While retaining all the operating modes and
features of the I2C-bus system during the level shifts, it also permits extension of the
I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL)
lines, thus enabling two buses of 400 pF. Using the PCA9508 enables the system
designer to isolate two halves of a bus for both voltage and capacitance, and perform
hot-swap and voltage level translation. Furthermore, the dual supply pins can be powered
up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are
high-impedance.
The hot swap feature allows an I/O card to be inserted into a live backplane without
corrupting the data and clock buses. Control circuitry prevents the backplane from being
connected to the card until a stop command or bus idle occurs on the backplane without
bus contention on the card. Zero offset output voltage allows multiple PCA9508s to be put
in series and still maintains an excellent noise margin.
PCA9508 has B side and A side bus drivers. The 2.7 V to 5.5 V bus B side drivers behave
much like the drivers on the PCA9515A device, while the adjustable voltage bus A side
drivers drive more current and incur no static offset voltage. This results in a LOW on the
B side translating into a nearly 0 V LOW on the A side.
The static offset design of the B side PCA9508 I/O drivers prevents them from being
connected to another device that has a rise time accelerator including the PCA9510/A,
PCA9511/A, PCA9512/A, PCA9513/A, or PCA9514/A or a static offset voltage including
the PCA9507 (B side), PCA9508 (B side), PCA9509 (A side), PCA9515/A, PCA9516A,
PCA9517/A (B side), PCA9518, PCA9519 (A side), or P82B96/PCA9600 (Sx/Sy side).
The A side of two or more PCA9508s can be connected together, however, to allow a star
topology with the A side on the common bus, and the A side can be connected directly to
any other buffer with static or dynamic offset voltage. Multiple PCA9508s can be
connected in series, A side to B side, with no build-up in offset voltage with only
time-of-flight delays to consider.
The PCA9508 drivers are not enabled unless the bus is idle, VCC(A) is above 0.8 V and
VCC(B) is above 2.5 V. The EN pin can also be used to turn the drivers on and off under
system control. Caution should be observed to only change the state of the enable pin
when the bus is idle.
The output pull-down on the B side internal buffer LOW is set for approximately 0.5 V,
while the input threshold of the internal buffer is set about 70 mV lower (0.43 V). When the
B side I/O is driven LOW internally, the LOW is not recognized as a LOW by the input.
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
This prevents a lock-up condition from occurring. The output pull-down on the A side
drives a hard LOW and the input level is set at 0.5VCC(A) to accommodate the need for a
lower LOW level in systems where the low voltage side supply voltage is as low as 0.9 V.
Table 1 shows the comparison between PCA9508 and I2C-bus repeaters.
Table 1.
PCA9508 and I2C-bus repeaters comparison
PCA9517A[1]
Feature
PCA9507
PCA9508
PCA9509
VCC(A) range (V)
2.7 to 5.5
0.9 to 5.5
1.1 to VCC(B) − 1 0.9 to 5.5
1.1 to VCC(B) − 1
VCC(B) range (V)
2.7 to 5.5
2.7 to 5.5
3.0 to 5.5
2.7 to 5.5
3.0 to 5.5
rise time
accelerator
yes
-
-
-
-
idle/stop detect
for hot-swap
-
yes
-
-
-
normal I/O
A side
A side
B side
A side
B side
static level offset
B side
B side
A side
B side
A side
[1]
PCA9519
PCA9517A is the high ESD (6.5 kV HBM and 550 V MM) drop-in replacement for PCA9517.
2. Features
n 2 channel, bidirectional buffer isolates capacitance and allows 400 pF on either side of
the device
n Supports offset-free hot-swap with IDLE/STOP detect circuitry
n Voltage level translation from 0.9 V to 5.5 V and from 2.7 V to 5.5 V
n Footprint and functional replacement for PCA9515, PCA9515A, PCA9517 and
PCA9517A
n I2C-bus and SMBus compatible
n Active HIGH repeater enable input
n Static level offset on B side
n Open-drain input/outputs
n Lock-up free operation
n Supports arbitration and clock stretching across the repeater
n Accommodates Standard-mode and Fast-mode I2C-bus devices and multiple masters
n Powered-off high-impedance I2C-bus pins
n A side operating supply voltage range of 0.9 V to 5.5 V
n B side operating supply voltage range of 2.7 V to 5.5 V
n 5 V tolerant I2C-bus and enable pins
n 0 Hz to 400 kHz clock frequency (the maximum system operating frequency may be
less than 400 kHz because of the delays added by the repeater).
n ESD protection exceeds 6000 V HBM per JESD22-A114, 450 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 Packages offered: SO8 and TSSOP8
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
2 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
3. Ordering information
Table 2.
Ordering information
Tamb = −40 °C to +85 °C.
Type number
Topside
mark
Package
Name
PCA9508D
PCA9508 SO8
PCA9508DP
9508
[1]
Description
Version
plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
TSSOP8[1] plastic thin shrink small outline package; 8 leads; body width 3 mm
SOT505-1
Also known as MSOP8.
4. Functional diagram
VCC(B)
VCC(A)
PCA9508
SDAA
SDAB
SCLA
SCLB
CONNECT
0.55VCC/
0.45VCC
STOP BIT AND
BUS IDLE
VCC(B)
0.5 µA
pull-up
resistor
0.55VCC/
0.45VCC
UVLO
EN
20 pF
100 µs
DELAY
UVLO
RD
QB
CONNECT
S
0.5 pF
002aac651
Fig 1.
Functional diagram of PCA9508
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
3 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
5. Pinning information
5.1 Pinning
VCC(A)
1
8
VCC(B)
SCLA
2
7
SCLB
SDAA
3
6
SDAB
GND
4
5
EN
VCC(A)
1
8
VCC(B)
SCLA
2
7
SCLB
SDAA
3
6
SDAB
GND
4
5
EN
PCA9508D
PCA9508DP
002aac653
002aac652
Fig 2.
Pin configuration for SO8
Fig 3.
Pin configuration for TSSOP8
5.2 Pin description
Table 3.
Pin description
Symbol
Pin
Description
VCC(A)
1
A side supply voltage (0.9 V to 5.5 V)
SCLA
2
open-drain input/output serial clock A side bus
SDAA
3
open-drain input/output serial data A side bus
GND
4
supply ground (0 V)
EN
5
active HIGH repeater enable input with an internal pull-up (100 kΩ)
SDAB
6
open-drain input/output serial data B side bus
SCLB
7
open-drain input/output serial clock B side bus
VCC(B)
8
B side supply voltage (2.7 V to 5.5 V)
6. Functional description
Refer to Figure 1 “Functional diagram of PCA9508”.
The PCA9508 enables I2C-bus or SMBus translation down to VCC(A) as low as 0.9 V
without degradation of system performance. The PCA9508 contains two bidirectional
open-drain buffers specifically designed to provide superior hot-swap and/or support
up-translation/down-translation between the low voltage (as low as 0.9 V) and a 3.3 V or
5 V I2C-bus or SMBus. All inputs and I/Os are overvoltage tolerant to 5.5 V even when the
device is unpowered (VCC(B) and/or VCC(A) = 0 V). The PCA9508 includes a power-up
circuit that keeps the output drivers turned off until VCC(B) is above 2.5 V and the VCC(A) is
above 0.8 V. VCC(B) and VCC(A) can be applied in any sequence at power-up. VCC(A) is only
used to provide the 0.5VCC(A) reference to the A side input comparators and for the power
good detect circuit. The PCA9508 logic and all I/Os are powered by the VCC(B) pin.
An undervoltage/initialization circuit holds the PCA9508 in a disconnected state which
presents high-impedance to all SDA and SCL pins during power-up. A LOW on the enable
pin (EN) also forces the parts into the disconnected state. As the power supply is brought
up and EN is HIGH or the part is powered and EN is taken from LOW to HIGH it enters an
initialization state where the internal references are stabilized. At the end of the
initialization state the ‘STOP bit and bus idle’ detect circuit is enabled. With the EN pin
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
4 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
HIGH long enough to complete the initialization state (ten) and remaining HIGH when all
the SDA and SCL pins have been HIGH for the bus idle time or when all pins are HIGH
and a STOP condition is seen on the SDAA and SCLA pins, SDAA is connected to SDAB
and SCLA is connected to SCLB.
6.1 A side to B side
Once connected, when the PCA9508 senses a LOW level on the A side (below
0.5VCC(A)), it turns on the corresponding B side driver (either SDA or SCL) and drives the
B side down to about 0.5 V. When the external driver turns off, the A side will begin to rise
as it is pulled HIGH by the bus pull-up resistor. When the A side reaches 0.5VCC(A), the
B side driver turns off and both A and B will continue to rise. The result is two smooth
exponential rising edges on both buses with a propagation delay between them which is a
function of the RC time constant on the A side bus.
6.2 B side to A side
When a LOW level is sensed on the B side (below 0.4 V), the corresponding A side driver
is turned on to drive the A side to nearly 0 V. When the external driver turns off, the B side
will begin to rise as it is pulled HIGH by the bus pull-up resistor. When the B side reaches
0.5 V, the A side driver will turn off. The B side driver will remain at about 0.5 V until the
A side rises above 0.5VCC(A), then the B side will continue to rise. The result is a plateau
on the B side rising edge. See Figure 11.
6.3 Weak drive on B side
The following condition should be avoided as it causes the PCA9508 to create a glitch on
the bus. As long as I2C-bus devices connected to the B side can pull the bus lines lower
than 0.4 V, this problem will never occur. When the B side falls first and goes below
0.3VCC(B), the A side driver is turned on and the A side is pulled down to 0 V. The B side
pull-down is switched on and unless the B side is pulled below 0.4 V by an external driver,
the A side pull-down will switch off and the A side will be pulled up by the pull-up resistor.
When the A side rises above 0.5VCC(A), the B side pull-down will turn off. To prevent this
glitch, it is necessary to make certain that the B side LOW level driven by an external
driver is below 0.4 V.
6.4 Enable pin (EN)
The EN pin is active HIGH with an internal pull-up to VCC(B) and allows the user to select
when the repeater is active. This can be used to isolate a badly behaved slave on
power-up until after the system power-up reset. It should never change state during an
I2C-bus operation because disabling during a bus operation will hang the bus.
The EN pin should only change state when the global bus and the repeater port are in an
idle state to prevent system failures.
If the PCA9508 is enabled while the bus is active, the PCA9508 will connect at the first
STOP signal or at the first gap in activity that satisfies the internal idle bus time after the
enable sequence is complete.
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
5 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
6.5 I2C-bus systems
As with the standard I2C-bus system, pull-up resistors are required to provide the logic
HIGH levels on the buffered bus (standard open-collector configuration of the I2C-bus).
The size of these pull-up resistors depends on the system, but each side of the repeater
must have a pull-up resistor. This part designed to work with Standard-mode and
Fast-mode I2C-bus devices in addition to SMBus devices. Standard-mode I2C-bus devices
only specify 3 mA output drive; this limits the termination current to 3 mA in a generic
I2C-bus system where Standard-mode devices and multiple masters are possible. Under
certain conditions higher termination currents can be used.
Please see application note AN255, I2C/SMBus Repeaters, Hubs and Expanders for
additional information on sizing resistors and precautions when using more than one
PCA9508 in a system or using the PCA9508 in conjunction with other bus buffers.
7. Application design-in information
A typical application is shown in Figure 4. In this example, the system master is running
on a 3.3 V I2C-bus while the slave is connected to a 1.2 V bus. Both buses run at 400 kHz.
Master devices can be placed on either bus.
3.3 V
10 kΩ
1.2 V
10 kΩ
10 kΩ
VCC(B)
10 kΩ
VCC(A)
SDA
SDAB
SDAA
SDA
SCL
SCLB
SCLA
SCL
BUS
MASTER
400 kHz
PCA9508
SLAVE
400 kHz
EN
bus B
Fig 4.
bus A
002aac654
Typical application
The PCA9508 is 5 V tolerant, so it does not require any additional circuitry to translate
between 0.9 V to 5.5 V bus voltages and 2.7 V to 5.5 V bus voltages.
When the A side of the PCA9508 is pulled LOW by a driver on the I2C-bus, a comparator
detects the falling edge when it goes below 0.5VCC(A) and causes the internal driver on the
B side to turn on, causing the B side to pull down to about 0.5 V. When the B side of the
PCA9508 falls, first a CMOS hysteresis type input detects the falling edge and causes the
internal driver on the A side to turn on and pull the A side pin down to ground. In order to
illustrate what would be seen in a typical application, refer to Figure 7 and Figure 8. If the
bus master in Figure 4 were to write to the slave through the PCA9508, waveforms shown
in Figure 7 would be observed on the A bus. This looks like a normal I2C-bus transmission
except that the HIGH level may be as low as 0.9 V, and the turn on and turn off of the
acknowledge signals are slightly delayed.
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
6 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
On the B bus side of the PCA9508, the clock and data lines would have a positive offset
from ground equal to the VOL of the PCA9508. After the 8th clock pulse, the data line will
be pulled to the VOL of the slave device, which is very close to ground in this example. At
the end of the acknowledge, the level rises only to the LOW level set by the driver in the
PCA9508 for a short delay while the A bus side rises above 0.5VCC(A) then it continues
HIGH. It is important to note that any arbitration or clock stretching events require that the
LOW level on the B bus side at the input of the PCA9508 (VIL) be at or below 0.4 V to be
recognized by the PCA9508 and then transmitted to the A bus side.
Multiple PCA9508 A sides can be connected in a star configuration (Figure 5), allowing all
nodes to communicate with each other.
Multiple PCA9508s can be connected in series (Figure 6) as long as the A side is
connected to the B side. I2C-bus slave devices can be connected to any of the bus
segments. The number of devices that can be connected in series is limited by repeater
delay/time-of-flight considerations on the maximum bus speed requirements.
VCC(A)
10 kΩ
VCC(B)
10 kΩ
10 kΩ
VCC(A)
10 kΩ
VCC(B)
SDA
SDAA
SDAB
SDA
SCL
SCLA
SCLB
SCL
BUS
MASTER
PCA9508
SLAVE
400 kHz
EN
10 kΩ
VCC(A)
10 kΩ
VCC(B)
SDAA
SDAB
SDA
SCLA
SCLB
SCL
PCA9508
SLAVE
400 kHz
EN
10 kΩ
VCC(A)
10 kΩ
VCC(B)
SDAA
SDAB
SDA
SCLA
SCLB
SCL
PCA9508
SLAVE
400 kHz
EN
002aac655
Fig 5.
Typical star application
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
7 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
VCC
10 kΩ
10 kΩ
10 kΩ
10 kΩ
10 kΩ
10 kΩ
10 kΩ
10 kΩ
SDA
SDAA
SDAB
SDAA
SDAB
SDAA
SDAB
SDA
SCL
SCLA
SCLB
SCLA
SCLB
SCLA
SCLB
SCL
BUS
MASTER
hot-swap
and
offset free
PCA9508
EN
hot-swap
and
offset free
PCA9508
hot-swap
and
offset free
PCA9508
SLAVE
400 kHz
EN
EN
002aac656
Fig 6.
Typical series application
9th clock pulse
acknowledge
SCL
SDA
002aac204
Fig 7.
Bus A (0.9 V to 5.5 V bus) waveform
9th clock pulse
acknowledge
SCL
SDA
VOL of PCA9508
002aac657
VOL of slave
Fig 8.
Bus B (2.7 V to 5.5 V) waveform
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
8 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
8. Limiting values
Table 4.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Parameter
Conditions
Min
Max
Unit
VCC(B)
supply voltage port B
2.7 V to 5.5 V
−0.5
+7
V
VCC(A)
supply voltage port A
adjustable
−0.5
+7
V
VI/O
voltage on an input/output pin
SDAA, SDAB, SCLA, SCLB, EN
−0.5
+7
V
II
input current
any pin
-
50
mA
Ptot
total power dissipation
-
100
mW
−55
+125
°C
−40
+85
°C
-
+125
°C
Tstg
storage temperature
Tamb
ambient temperature
Tj
junction temperature
operating in free air
9. Static characteristics
Table 5.
Static characteristics
VCC = 2.7 V to 5.5 V; GND = 0 V; Tamb = −40 °C to +85 °C; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
2.7
-
5.5
V
0.9
-
5.5
V
Supplies
VCC(B)
supply voltage port B
[1]
VCC(A)
supply voltage port A
ICC(A)
supply current port A
pin VCC(A)
-
-
1
mA
ICCH
HIGH-level supply current
both channels HIGH;
VCC = 5.5 V;
SDAn = SCLn = VCC
-
1.5
3
mA
ICCL
LOW-level supply current
both channels LOW;
VCC = 5.5 V; one SDA and
one SCL = GND; other SDA
and SCL open
-
1.5
3
mA
ICC(A)c
contention port A supply current
VCC = 5.5 V;
SDAn = SCLn = VCC
-
1.5
3
mA
0.7VCC(B) -
5.5
V
−0.5
-
+0.3VCC(B) V
Input and output SDAB and SCLB
VIH
HIGH-level input voltage
VIL
LOW-level input voltage
[2]
VILc
contention LOW-level input voltage
−0.5
0.4
-
V
VIK
input clamping voltage
II = −18 mA
-
-
−1.2
V
ILI
input leakage current
VI = 3.6 V
-
-
±1
µA
IIL
LOW-level input current
SDA, SCL; VI = 0.2 V
-
-
10
µA
VOL
LOW-level output voltage
IOL = 100 µA or 6 mA
0.47
0.52
0.6
V
VOL−VILc
difference between LOW-level
guaranteed by design
output and LOW-level input voltage
contention
-
-
70
mV
ILOH
HIGH-level output leakage current
VO = VCC
-
-
10
µA
Cio
input/output capacitance
VI = 3 V or 0 V; VCC = 3.3 V
-
5.2
7
pF
VI = 3 V or 0 V; VCC = 0 V
-
5.2
7
pF
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
9 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
Table 5.
Static characteristics …continued
VCC = 2.7 V to 5.5 V; GND = 0 V; Tamb = −40 °C to +85 °C; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Input and output SDAA and SCLA
VIH
HIGH-level input voltage
0.6VCC(A) 0.5VCC(A) 5.5
V
VIL
LOW-level input voltage
−0.5
-
+0.4VCC(A) V
VIK
input clamping voltage
II = −18 mA
-
-
−1.2
V
ILI
input leakage current
VI = 3.6 V
-
-
±1
µA
IIL
LOW-level input current
SDA, SCL; VI = 0.2 V
-
-
10
µA
VOL
LOW-level output voltage
IOL = 6 mA
-
0.1
0.2
V
ILOH
HIGH-level output leakage current
VO = VCC
-
-
10
µA
Cio
input/output capacitance
VI = 3 V or 0 V; VCC = 3.3 V
-
5.2
7
pF
VI = 3 V or 0 V; VCC = 0 V
-
5.2
7
pF
-
+0.3VCC(B) V
Enable
VIL
LOW-level input voltage
−0.5
VIH
HIGH-level input voltage
0.7VCC(B) -
IIL(EN)
LOW-level input current on pin EN
ILI
Ci
5.5
V
VI = 0.2 V, EN; VCC = 3.6 V
-
−10
−30
µA
input leakage current
VI = VCC
−1
-
+1
µA
input capacitance
VI = 3.0 V or 0 V
-
1.7
7
pF
[1]
LOW-level supply voltage.
[2]
VIL specification is for the first LOW level seen by the SDAB/SCLB lines. VILc is for the second and subsequent LOW levels seen by the
SDAB/SCLB lines.
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
10 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
10. Dynamic characteristics
Table 6.
Dynamic characteristics
VCC = 2.7 V to 5.5 V; GND = 0 V; Tamb = −40 °C to +85 °C; unless otherwise specified.[1][2]
Symbol
Parameter
Min
Typ[3]
Max
Unit
[4]
100
170
250
ns
[5]
20
98
118
ns
20
76
164
ns
10
20
30
ns
1
72
83
ns
Conditions
tPLH
LOW-to-HIGH propagation delay
B side to A side; Figure 11
tPHL
HIGH-to-LOW propagation delay
B side to A side; Figure 9
VCC(A) < 3.0 V
VCC(A) > 3.0 V
tTLH
LOW to HIGH output transition time A side; Figure 10
tTHL
HIGH to LOW output transition time A side; Figure 10
VCC(A) < 2.7 V
[5]
VCC(A) > 3.0 V
LOW-to-HIGH propagation delay
tPLH
8
68
137
ns
A side to B side; Figure 10
[6]
25
53
110
ns
A side to B side; Figure 10
[6]
tPHL
HIGH-to-LOW propagation delay
60
79
230
ns
tTLH
LOW to HIGH output transition time B side; Figure 9
120
140
170
ns
tTHL
HIGH to LOW output transition time B side; Figure 9
30
48
90
ns
B side to A side; Figure 12
-
0.5
-
µs
B side to A side; Figure 13
50
105
200
µs
A side to B side; Figure 14
-
0.5
-
µs
EN HIGH before START condition
[10]
100
-
-
ns
EN HIGH after STOP condition
[10]
100
-
-
ns
tconnect
connect
time[7]
tidle(connect) connect idle
time[8]
tstop(connect) connect stop time[9]
set-up time
tsu
hold time
th
[1]
Times are specified with loads of 1.35 kΩ pull-up resistance and 57 pF load capacitance on the B side, and 167 Ω pull-up resistance
and 57 pF load capacitance on the A side. Different load resistance and capacitance will alter the RC time constant, thereby changing
the propagation delay and transition times.
[2]
Pull-up voltages are VCC(A) on the A side and VCC(B) on the B side.
[3]
Typical values were measured with VCC(A) = 3.3 V at Tamb = 25 °C, unless otherwise noted.
[4]
The tPLH delay data from B side to A side is measured at 0.5 V on the B side to 0.5VCC(A) on the A side when VCC(A) is less than 2 V, and
1.5 V on the A side if VCC(A) is greater than 2 V.
[5]
Typical value measured with VCC(A) = 2.7 V at Tamb = 25 °C.
[6]
The proportional delay data from A side to B side is measured at 0.3VCC(A) on the A side to 1.5 V on the B side.
[7]
Defined as the time required to connect from B side to A side, after B side switches from active to idle, when A side is idle.
[8]
Defined as the time required to connect from B side to A side, when B side and A side are idle.
[9]
Defined as the time required to connect A side to B side, when B side is idle and A side is going active from idle, by a STOP condition.
[10] The enable pin, EN, should only change state when the global bus and the repeater port are in an idle state.
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
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Hot swappable level translating I2C-bus repeater
10.1 AC waveforms
3.0 V
input
1.5 V
1.5 V
tPHL
tPLH
80 %
output
0.6 V
20 %
tTHL
0.6 V
20 %
VCC(A)
input
0.1 V
tPHL
1.2 V
80 %
0.3VCC(A)
tPLH
3.0 V
80 %
1.5 V
20 %
output
VOL
tTLH
tTHL
002aad642
Fig 9.
Propagation delay and transition times;
B side to A side
0.3VCC(A)
1.5 V
20 %
80 %
tTLH
002aad643
Fig 10. Propagation delay and transition times;
A side to B side
input
SDAB, SCLB
0.5 V
output
SCLA, SDAA
50 % if VCC(A) is less than 2 V
1.5 V if VCC(A) is greater than 2 V
tPLH
002aad641
Fig 11. Propagation delay; B side to A side
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
12 of 21
PCA9508
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Hot swappable level translating I2C-bus repeater
wait 200 µs
wait 200 µs
VCC
EN
SDAA
0V
VCC
tconnect
0V
move until
SCLA goes LOW
SCLB
VCC
EN
0V
SCLA
VCC
tconnect
0V
move until
SDAA goes LOW
SDAB
SDAB
SCLB
SCLA
SDAA
002aad716
Fig 12. tconnect timing
EN
VCC
SCLB
SDAB
EN
tidle(connect)
0V
move until
SDAA goes LOW
tidle(connect)
VCC
SDAB
0V
move until
SCLA goes LOW
SCLB
SCLA
SDAA
VCC
SCLA
0V
VCC
SDAA
0V
002aad717
Fig 13. tidle(connect) timing
VCC
EN
0V
move until
SCLB goes LOW
SCLA
tstop(connect)
SDAA
SCLB
VCC
SDAB
0V
002aad718
Fig 14. tstop(connect) timing
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
13 of 21
PCA9508
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11. Test information
VCC(B)
VCC(B)
VCC(A)
PULSE
GENERATOR
VI
RL
VO
DUT
CL
RT
002aab649
RL = load resistor; 1.35 kΩ on B side; 167 Ω on A side
CL = load capacitance includes jig and probe capacitance; 57 pF
RT = termination resistance should be equal to Zo of pulse generators
Fig 15. Test circuit for open-drain outputs
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
14 of 21
PCA9508
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Hot swappable level translating I2C-bus repeater
12. Package outline
SO8: plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
D
E
A
X
c
y
HE
v M A
Z
5
8
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
1
L
4
e
detail X
w M
bp
0
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (2)
e
HE
L
Lp
Q
v
w
y
Z (1)
mm
1.75
0.25
0.10
1.45
1.25
0.25
0.49
0.36
0.25
0.19
5.0
4.8
4.0
3.8
1.27
6.2
5.8
1.05
1.0
0.4
0.7
0.6
0.25
0.25
0.1
0.7
0.3
inches
0.069
0.010 0.057
0.004 0.049
0.01
0.019 0.0100
0.014 0.0075
0.20
0.19
0.16
0.15
0.05
0.01
0.01
0.004
0.028
0.012
0.244
0.039 0.028
0.041
0.228
0.016 0.024
θ
8o
o
0
Notes
1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT96-1
076E03
MS-012
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-12-27
03-02-18
Fig 16. Package outline SOT96-1 (SO8)
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
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PCA9508
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TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm
D
E
SOT505-1
A
X
c
y
HE
v M A
Z
5
8
A2
pin 1 index
(A3)
A1
A
θ
Lp
L
1
4
detail X
e
w M
bp
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
v
w
y
Z(1)
θ
mm
1.1
0.15
0.05
0.95
0.80
0.25
0.45
0.25
0.28
0.15
3.1
2.9
3.1
2.9
0.65
5.1
4.7
0.94
0.7
0.4
0.1
0.1
0.1
0.70
0.35
6°
0°
Notes
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
2. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
OUTLINE
VERSION
REFERENCES
IEC
JEDEC
JEITA
EUROPEAN
PROJECTION
ISSUE DATE
99-04-09
03-02-18
SOT505-1
Fig 17. Package outline SOT505-1 (TSSOP8)
PCA9508_1
Product data sheet
© NXP B.V. 2008. All rights reserved.
Rev. 01 — 28 April 2008
16 of 21
PCA9508
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Hot swappable level translating I2C-bus repeater
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
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
17 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
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 18) 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 7 and 8
Table 7.
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 8.
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 18.
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
18 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
maximum peak temperature
= MSL limit, damage level
temperature
minimum peak temperature
= minimum soldering temperature
peak
temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 18. 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 9.
Abbreviations
Acronym
Description
CDM
Charged-Device Model
CMOS
Complementary Metal-Oxide Semiconductor
DUT
Device Under Test
ESD
ElectroStatic Discharge
HBM
Human Body Model
I2C-bus
Inter-Integrated Circuit bus
I/O
Input/Output
MM
Machine Model
RC
Resistor-Capacitor network
SMBus
System Management Bus
15. Revision history
Table 10.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
PCA9508_1
20080428
Product data sheet
-
-
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
19 of 21
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NXP Semiconductors
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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.
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: salesaddresses@nxp.com
PCA9508_1
Product data sheet
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Rev. 01 — 28 April 2008
20 of 21
PCA9508
NXP Semiconductors
Hot swappable level translating I2C-bus repeater
18. Contents
1
2
3
4
5
5.1
5.2
6
6.1
6.2
6.3
6.4
6.5
7
8
9
10
10.1
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 3
Functional diagram . . . . . . . . . . . . . . . . . . . . . . 3
Pinning information . . . . . . . . . . . . . . . . . . . . . . 4
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional description . . . . . . . . . . . . . . . . . . . 4
A side to B side. . . . . . . . . . . . . . . . . . . . . . . . . 5
B side to A side. . . . . . . . . . . . . . . . . . . . . . . . . 5
Weak drive on B side . . . . . . . . . . . . . . . . . . . . 5
Enable pin (EN) . . . . . . . . . . . . . . . . . . . . . . . . 5
I2C-bus systems . . . . . . . . . . . . . . . . . . . . . . . . 6
Application design-in information . . . . . . . . . . 6
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 9
Static characteristics. . . . . . . . . . . . . . . . . . . . . 9
Dynamic characteristics . . . . . . . . . . . . . . . . . 11
AC waveforms. . . . . . . . . . . . . . . . . . . . . . . . . 12
Test information . . . . . . . . . . . . . . . . . . . . . . . . 14
Package outline . . . . . . . . . . . . . . . . . . . . . . . . 15
Soldering of SMD packages . . . . . . . . . . . . . . 17
Introduction to soldering . . . . . . . . . . . . . . . . . 17
Wave and reflow soldering . . . . . . . . . . . . . . . 17
Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 17
Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 18
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Revision history . . . . . . . . . . . . . . . . . . . . . . . . 19
Legal information. . . . . . . . . . . . . . . . . . . . . . . 20
Data sheet status . . . . . . . . . . . . . . . . . . . . . . 20
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Contact information. . . . . . . . . . . . . . . . . . . . . 20
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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. 2008.
All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: salesaddresses@nxp.com
Date of release: 28 April 2008
Document identifier: PCA9508_1
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