Data Sheet

PCA9525
Simple 2-wire bus buffer
Rev. 1 — 25 February 2011
Product data sheet
1. General description
The PCA9525 is a monolithic CMOS integrated circuit for bus buffering in applications
including I2C-bus, SMBus, DDC, PMBus, and other systems based on similar principles.
The buffer extends the bus load limit by buffering both the SCL and SDA lines, allowing
the maximum permissible bus capacitance on both sides of the buffer.
The PCA9525 includes a unidirectional buffer for the clock signal, and a bidirectional
buffer for the data signal. Slave devices which employ clock stretching are therefore not
supported.
In its most basic implementation, the buffer will allow an extended number of slave
devices to be attached to one (or more) master devices. In this case, all master devices
would be positioned on the Sxx_IN side of the PCA9525.
The direction pin (DIR) further enhances this function by allowing the unidirectional clock
signal to be reversed, thus allowing master devices on both sides of the buffer.
The enable (EN) function allows sections of the bus to be isolated. Individual parts of the
system can be brought on-line successively. This means a controlled start-up using a
diverse range of components, operating speeds and loads is easily achieved.
2. Features and benefits
„ Simple impedance isolating buffer for 2-wire buses
„ 4 mA maximum static open-drain pull-down capability supports a wide range of bus
standards
„ Works with I2C-bus (Standard-mode, Fast-mode), SMBus (standard and high power
mode), and PMBus
„ Fast switching times allow operation in excess of 1 MHz
„ Enable allows bus segments to be disconnected
„ Hysteresis on inputs provides noise immunity
„ Operating voltages from 2.7 V to 5.5 V
„ Very low supply current
„ Uncomplicated characteristics suitable for quick implementation in most common
2-wire bus applications
PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
3. Applications
„
„
„
„
„
„
„
Electronic signs and displays
Game consoles/boxes
Gaming machine networks
TV/projector/monitor interconnection (DDC)
Power management systems
Desktop and portable computers
Security systems
4. Ordering information
Table 1.
Ordering information
Type number
Topside
mark
Package
Name
Description
Version
PCA9525D
PCA9525
SO8
plastic small outline package; 8 leads; body width 3.9 mm
SOT96-1
PCA9525DP
9525
TSSOP8
plastic thin shrink small outline package; 8 leads; body width 3 mm
SOT505-1
5. Block diagram
2.7 V to 5.5 V
VDD
R1
enable
SDA
SCL
direction
R2
R3
8
EN 1
R4
PCA9525
SDA_IN 6
7 SDA_OUT
SCL_IN 3
2 SCL_OUT
SDA
SCL
DIR 5
4
VSS
002aaf329
Fig 1.
PCA9525
Product data sheet
Block diagram of PCA9525
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© NXP B.V. 2011. All rights reserved.
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PCA9525
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Simple 2-wire bus buffer
6. Pinning information
6.1 Pinning
EN
1
8
VDD
SCL_OUT
2
7
SDA_OUT
SCL_IN
3
6
SDA_IN
VSS
4
5
DIR
PCA9525D
EN
1
8
VDD
SCL_OUT
2
7
SDA_OUT
SCL_IN
3
VSS
4
PCA9525DP
SDA_IN
5
DIR
002aaf331
002aaf330
Fig 2.
6
Pin configuration for SO8
Fig 3.
Pin configuration for TSSOP8
6.2 Pin description
Table 2.
Pin description
Symbol
Pin
Description
EN
1
enable
SCL_OUT
2
clock buffer, slave side
SCL_IN
3
clock buffer, master side
VSS
4
supply ground
DIR
5
clock direction
SDA_IN
6
data buffer, master side
SDA_OUT
7
data buffer, slave side
VDD
8
positive supply
7. Functional description
Refer to Figure 1 “Block diagram of PCA9525”.
7.1 VDD, VSS — supply pins
The power supply voltage for the PCA9525 may be any voltage in the range 2.7 V to
5.5 V. The IC supply must be common with the supply for the bus. Hysteresis on the ports
is a percentage of the IC’s power supply, hence noise margin considerations should be
taken into account when selecting an operating voltage.
7.2 SCL_IN, SCL_OUT — clock signal inputs/outputs
The clock signal buffer is unidirectional, although the direction may be reversed under
control of the direction pin (DIR). In normal bus operations, for example the I2C-bus, the
master device generates a unidirectional clock signal to the slave. For lowest cost, the
PCA9525 combines unidirectional buffering of the clock signal with a bidirectional buffer
for the data signal. Clock stretching is therefore not supported and slave devices that may
require clock stretching must be accommodated by the master adopting an appropriate
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
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3 of 22
PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
clocking when communicating with them. The buffer includes hysteresis to ensure clean
switching signals are output, especially with slow rise times on high capacitively loaded
buses. Output ports are open-drain type and require external pull-up resistors.
7.3 SDA_IN, SDA_OUT — data signal inputs/outputs
The data signal buffer is bidirectional. The port (SDA_IN, SDA_OUT) which first falls
below the ‘lock voltage’ Vlock, will take control of the buffer direction and ‘lock out’ signals
coming from the opposite side. As the ‘input’ signal continues to fall, it will then drive the
‘output’ side LOW. Again, hysteresis is applied to the buffer to minimize the effects of
noise.
At some points during the communication, the data direction will reverse, e.g., when the
slave transmits an acknowledge (ACK), or responds with its register contents. During
these times, the controlling ‘input’ side will have to rise back above the unlock voltage
(Vunlock) before it releases the ‘lock’, which then allows the ‘output’ side to gain control,
and pull (what was) the ‘input’ side LOW again. This will cause a ‘pulse’ on the ‘input’ side,
which can be quite a long duration in high capacitance buses. However, this pulse will not
interfere with the actual data transmission, as it should not occur during times of clock line
transition (during normal I2C-bus and SMBus protocols), and thus data signal set-up time
requirements are still met. Ports are open-drain type and require external pull-up resistors.
7.4 Enable (EN) — activate buffer operations
The active HIGH enable input (EN) can be used to disable the buffer, for the purpose of
isolating sections of the bus. The IC should only be disabled when the bus is idle. This
prevents truncation of commands which may confuse other devices on the bus. Enable
(EN) may also be used to progressively activate sections of the bus during system
start-up. Bus sections slow to respond on power-up can be kept isolated from the main
system to avoid interference and collisions. The pin must be externally driven to a valid
state.
7.5 Direction (DIR) — clock buffer direction control
The direction input (DIR) is used to change the signal direction of the SCL ports. When the
DIR pin is logic LOW, the clock signal input is SCL_IN and the buffered output is
SCL_OUT. When the DIR pin is logic HIGH, the clock signal input is SCL_OUT and the
buffered output is SCL_IN. The pin must be externally driven to a valid state.
PCA9525
Product data sheet
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© NXP B.V. 2011. All rights reserved.
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PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
8. Limiting values
Table 3.
Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol
Min
Max
Unit
supply voltage
[1]
−0.3
+7
V
Vn
voltage on any other pin
[1]
VSS − 0.5 VDD + 0.5 V
II/O
input/output current
Ptot
VDD
Parameter
Conditions
-
20
mA
total power dissipation
-
300
mW
Tstg
storage temperature
−55
+125
°C
Tamb
ambient temperature
−40
+85
°C
[1]
any pin
operating
Voltages are specified with respect to pin 4 (VSS).
9. Characteristics
Table 4.
Characteristics
Tamb = −40 °C to +85 °C; voltages are specified with respect to ground (VSS); VDD = 5.5 V unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
2.7
-
5.5
V
-
-
1
μA
-
170
-
μA
Power supply
VDD
supply voltage
operating
IDD
supply current
quiescent; VDD = VI(EN) = 5.5 V
SCL_IN, SDA_IN = 800 kHz;
VDD = 5.5 V
[1]
Buffer ports (SDA_IN, SCL_IN, SDA_OUT, SCL_OUT)
VI2C-bus
VIL
VIH
VI(hys)
I2C-bus voltage
LOW-level input voltage
HIGH-level input voltage
hysteresis of input voltage
-
-
VDD + 0.3
V
VDD = 2.7 V
[2]
-
-
0.4
V
VDD = 5.5 V
[2]
-
-
0.5
V
VDD = 2.7 V
[2]
1.2
-
-
V
VDD = 5.5 V
[2]
2.0
-
-
V
VDD = 2.7 V
[2]
80
-
-
mV
VDD = 5.5 V
[2]
200
-
-
mV
ILI
input leakage current
VI2C-bus = VDD or GND
−1
-
+1
μA
IO(sink)
output sink current
LOW-level; VI2C-bus < VIL
4
-
-
mA
VOL
LOW-level output voltage
IOL = 4 mA
-
80
300
mV
IOL = 100 μA
-
3
-
mV
Pins SDA_IN, SDA_OUT
Vlock
Vunlock
direction lock voltage
direction unlock voltage
PCA9525
Product data sheet
VDD = 2.7 V
[2]
-
-
1.3
V
VDD = 5.5 V
[2]
-
-
3.0
V
VDD = 2.7 V
[2]
2.0
-
-
V
VDD = 5.5 V
[2]
4.8
-
-
V
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PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
Table 4.
Characteristics …continued
Tamb = −40 °C to +85 °C; voltages are specified with respect to ground (VSS); VDD = 5.5 V unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
EN active; VDD = 2.7 V
2.0
-
-
V
EN active; VDD = 5.5 V
4.8
-
-
V
EN standby; VDD = 2.7 V
-
-
0.9
V
EN standby; VDD = 5.5 V
-
-
2.1
V
VDD = 2.7 V
100
-
-
mV
VDD = 5.5 V
200
-
-
mV
VI = VDD
-
-
±0.1
μA
VDD = 2.7 V
2.0
-
-
V
VDD = 5.5 V
4.8
-
-
V
VDD = 2.7 V
-
-
0.9
V
VDD = 5.5 V
Enable (EN)
Vth(en)
enable threshold voltage
Vth(dis)
disable threshold voltage
Vhys
hysteresis voltage
ILI
input leakage current
Direction (DIR)
VI(dir)
direction input voltage
direction SCL_OUT to SCL_IN
direction SCL_IN to SCL_OUT
Vhys
hysteresis voltage
input leakage current
ILI
-
-
2.1
V
VDD = 2.7 V
100
-
-
mV
VDD = 5.5 V
200
-
-
mV
VI = VDD
-
-
±0.1
μA
Timing characteristics (Figure 4)
td
tf
delay time
RPU = 620 Ω
[1]
-
17
-
ns
fall time
RPU = 620 Ω
[1]
-
3.5
-
ns
[1]
Guaranteed by design, not subject to test.
[2]
Supply voltage dependent; refer to graphs (Figure 5 through Figure 8) for typical trend.
VI2C-bus
70 % VDD
30 % VDD
30 % VDD
Sxx_IN
Sxx_OUT
td
tf
time
002aaf332
Fig 4.
PCA9525
Product data sheet
Timing diagram
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PCA9525
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Simple 2-wire bus buffer
002aaf333
5
4
1000
VI(hys)
(V)
800
3
600
VI
(V)
002aaf334
Tamb = +85 °C
+25 °C
−40 °C
Vlock
2
400
VIH
1
200
VIL
0
0
2
3
4
5
6
2
3
4
5
6
VDD (V)
VDD (V)
Tamb = 25 °C
Fig 5.
Typical input levels versus supply voltage
002aaf335
100
VOL
(mV)
80
Typical VIH − VIL hysteresis versus supply
voltage
Fig 6.
002aaf336
300
VOL
(mV)
VDD = 5.5 V
2.7 V
200
60
40
100
20
VDD = 5.5 V
2.7 V
0
0
2
4
6
0
−50
8
10
RPU (kΩ)
Tamb = 25 °C
Fig 7.
0
50
100
150
Tamb (C)
IOL = 4 mA
Typical LOW-level output voltage versus
pull-up resistance
Fig 8.
Typical LOW-level output voltage versus
ambient temperature
9.1 Bidirectional data buffer
The bidirectional data buffer will determine which side has first fallen below Vlock and give
that side of the buffer control over the direction of the buffer. For the purpose of this one
LOW-going pulse, that side now becomes the ‘input’ (be it SDA_IN or SDA_OUT).
When the ‘input’ side falls to near VIL, it will begin to drive the ‘output’ side of the buffer
LOW. It will continue to hold the ‘output’ low until the ‘input’ exceeds VIH at which point the
‘output’ is released and will rise as fast as it is permitted by the load and pull-up to which it
is attached. (Assuming, of course, that the ‘output’ is not otherwise held LOW by some
other device on the bus on that side of the buffer.)
When the ‘input’ side again exceeds Vunlock, it will release its control of the buffer direction.
At this point, if the ‘output’ side was being held LOW (< Vlock) by another device, it will
immediately gain control and now become the ‘input’. What was the ‘input’ will now
become the ‘output’, and the process will repeat as above, but in the opposite direction.
PCA9525
Product data sheet
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PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
This means that as direction control is handed from one side of the buffer to the other, a
voltage ‘spike’ of about Vunlock volts will appear on the side that was the ‘input’ and
became the ‘output’.
Figure 9 shows clock and data being buffered through the PCA9525. Channel 3 shows
the SDA_IN port, with direction ‘hand over’ spike (upper left corner). The level of the
SDA_OUT port (channel 4) can be seen to increase as it goes from being held LOW by
the buffer, to being held LOW by another device on the bus.
Of course, the information on the SDA line is only latched into an I2C-bus device on a
clock edge. The spike on the data line does not occur at a time when data is being
latched, and thus the set-up and hold conditions are still met for a valid I2C-bus
transaction.
Figure 9 also shows a glitch occurring on the SDA_OUT port (upper right corner). A more
drastic example is shown in Figure 10. In this case, the side acting as the ‘input’
(SDA_OUT) is more lightly loaded than the side acting as the ‘output’ (SDA_IN). It
therefore rises quickly to Vunlock level, before the SDA_IN has been able to exceed VIL.
Direction control briefly reverses, and SDA_OUT gets pulled back LOW again until
SDA_IN has exceeded VIH.
002aaf337
Fig 9.
‘Hand over’ spikes on the data bus
PCA9525
Product data sheet
002aaf338
Fig 10. Fast rising SDA_xx ‘input’ side
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PCA9525
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Simple 2-wire bus buffer
Figure 11 shows that by choosing an appropriate value of pull-up resistance (or adding
additional load capacitance if that is preferred), the rate of rise of both input and output
can be matched, and the glitch on the rising edge eliminated.
002aaf339
Fig 11. Matched ‘input’ and ‘output’ rise times
9.2 Operating conditions
A full byte transaction is shown in Figure 12. SDA_IN and SDA_OUT are shown at the top
of the image, and SCL_IN and SCL_OUT are shown at the bottom. The START condition,
address bits, read/write bit, acknowledge bit and STOP condition can all be clearly seen.
002aaf340
Fig 12. Full 400 kHz I2C-bus address byte transaction
PCA9525
Product data sheet
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Simple 2-wire bus buffer
10. Application information
10.1 Design considerations
Figure 13 shows a typical data transfer through the PCA9525. The PCA9525 has
excellent application to extending loads and providing interfaces to connectors on high
speed microprocessor cards. PCA9525 can operate well in excess of the Fast-mode
400 kHz I2C-bus specification (Ref. 1). Rise times are determined simply by the side of
the buffer with the slowest RC time constant.
SCL
(clock)
SDA
(data)
A0
(master)
S
A1
(master)
A2
(master)
A3
(master)
A4
(master)
A5
(master)
purpose of bit (address bit 5)
START
sequence
device asserting data line (master/slave)
A6
(master)
W
(master)
ACK
(slave)
P
SDA direction
'hand over' pulses upon change
of device asserting the data line
STOP
sequence
master side of PCA9525/PCA9605
slave side of PCA9525/PCA9605
002aaf341
Remark: Input to output delay exaggerated for clarity.
Fig 13. Typical communication sequence through the PCA9525
Figure 14 shows a typical application for the PCA9525. In most applications there will be a
single master on the Sxx_IN side of the buffer. One or more PCA9525s can be connected
to this master, giving multiple isolated bus sections on which the slaves are located. Each
bus section can have the maximum permissible load capacitance, and this capacitance
will not influence any other bus section.
The master can control the enable (EN) signals such that each bus section can be
independently activated. This allows for slaves sharing the same address to be placed on
different bus sections and thus uniquely addressed.
The enable pin (EN) can similarly be used to interface buses of different operating
frequencies. When certain bus sections are enabled, the system frequency may be limited
by a bus section having a slave device specified only to 400 kHz (Fast-mode). When that
bus section is disabled, the slow slave is isolated and the remaining bus can be run at
1 MHz (Fast-mode Plus).
PCA9525
Product data sheet
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PCA9525
NXP Semiconductors
Simple 2-wire bus buffer
3.3 V
SCL_IN
VDD
SCL_OUT
SCL
SDA
SDA_IN
SDA_OUT
SDA
U5
U4
VDD
SCL
SLAVE
SDA
U1
MASTER/
SLAVE
VDD
PCA9525
SCL
SLAVE
U6
up to 400 pF load (PCA9525)
up to 400 pF load
(PCA9525)
or 4 nF load if only
PCA9605's used
(R1 and R2 = 110 Ω)
R5
110 Ω
R4
110 Ω
SCL_IN
VDD
SCL_OUT
SCL
SDA_IN
SDA_OUT
SDA
SLAVE
U7
VDD
U2
SCL
PCA9605
VDD
DIR
SCL
EN
SDA
VDD
SCL
SDA
DIR
SDA
EN
BUS MASTER
U3
R4
1.1 kΩ
SCL
SDA
VDD
R3
1.1 kΩ
R2
1.1 kΩ
R1
1.1 kΩ
SLAVE
U8
up to 4 nF load (PCA9605)
002aaf342
Fig 14. PCA9525 typical buffer application
Figure 15 shows the PCA9525 used with masters on both sides of the buffer. More than
one master may be used on the Sxx_IN side of the IC. However, to locate a master on the
Sxx_OUT side and have that master be able to communicate with devices on the Sxx_IN
side, it must either have direct control over the direction pin (DIR) of the PCA9525, or it
must request another controlling master to change the direction. In Figure 15, U4 uses an
IRQ to signal to U2 that is requests a direction change. Once in control, it could
alternatively use the bus to signal ‘release of control’.
PCA9525
Product data sheet
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PCA9525
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Simple 2-wire bus buffer
5V
R1
R3
R4
SCL
SCL_IN
VDD
SCL_OUT
SCL
SDA
SDA_IN
SDA_OUT
SDA
VDD
U1
SCL
IRQ
PCA9525
SDA
DIR
VDD
BUS MASTER
SCL
EN
SDA
VDD
R2
VDD
SCL
SDA
U2
MASTER/
SLAVE
MASTER
master U4 requests SCL
direction change from
master U2 using IRQ
U4
SLAVE
U5
U3
002aaf343
Fig 15. PCA9525 with masters on both sides of buffer
Multiplexers such as the PCA9544A are simple analog switches which provide no
capacitive load isolation between connected branches. Figure 16 shows the PCA9525
enhancing an I2C-bus multiplexer application by isolating the load capacitance of each
branch. Figure 17 and Figure 18 show alternate forms of bus multiplexing, with the latter
being an excellent way to eliminate the requirement for a master to dedicate pins to
enabling multiple PCA9525 devices.
3.3 V
R1
1.5 kΩ
VCC
SCL
SDA
BUS MASTER
R3
1.1 kΩ
R2
1.5 kΩ
SCL_IN
SDA_IN
EN
R4
1.1 kΩ
VDD
SCL_OUT
SCL
SDA_OUT
SDA
U2
SC0
SD0
SC1
PCA9525
DIR
U1
VDD
INT[3:0]
SD1
SC2
A0
SD2
A1
SC3
A2
SD3
Using the PCA9525,
up to 400 pF may be
connected to each
and every bus 0
through bus 3.
PCA9544A
U3
002aaf344
Alternately, using the PCA9546A, (which allows multiple outputs to be selected) you would simply
place a PCA9525 on each output on the right hand side, rather than a single PCA9525 on the
left hand side.
Fig 16. PCA9525 multiplexer isolation application
PCA9525
Product data sheet
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PCA9525
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Simple 2-wire bus buffer
5V
R1
1.8 kΩ
R2
1.8 kΩ
SCL
SCL_IN
VDD
SCL_OUT
SDA
SDA_IN
SDA_OUT
EN
A
B
C
VCC
74LS137
3-to-8
demultiplexer
PCA9525
DIR
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
U1
VDD
SCL_OUT
SDA_IN
SDA_OUT
PCA9605
DIR
U3
SDA
isolated bus with
400 pF load capacitance
5V
SCL_IN
EN
SCL
SCL
SDA
isolated bus with
4 nF load capacitance
U2
002aaf345
Fig 17. PCA9525 bus multiplexer application driven from a simple logic device
3.3 V
R1
1.1 kΩ
R2
1.1 kΩ
SCL
SCL_IN
VDD
SCL_OUT
SCL
SDA
SDA_IN
SDA_OUT
SDA
EN
VDD
SCL
SDA
I2C-bus
I/O expander
IO0
IO1
IO2
IO3
PCA9536
U3
PCA9525
DIR
U1
3.3 V
SCL_IN
VDD
SCL_OUT
SDA_IN
SDA_OUT
EN
DIR
isolated bus with
400 pF load capacitance
PCA9605
SCL
SDA
isolated bus with
4 nF load capacitance
U2
002aaf346
Fig 18. PCA9525 bus multiplexer application driven from an I2C-bus I/O expander
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
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Simple 2-wire bus buffer
11. 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
L
4
1
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 19. Package outline SOT96-1 (SO8)
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
© NXP B.V. 2011. All rights reserved.
14 of 22
PCA9525
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Simple 2-wire bus buffer
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 20. Package outline SOT505-1 (TSSOP8)
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
© NXP B.V. 2011. All rights reserved.
15 of 22
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12. Handling information
CAUTION
This device is sensitive to ElectroStatic Discharge (ESD). Observe precautions for handling
electrostatic sensitive devices.
Such precautions are described in the ANSI/ESD S20.20, IEC/ST 61340-5, JESD625-A or
equivalent standards.
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:
•
•
•
•
•
•
PCA9525
Product data sheet
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
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 25 February 2011
© NXP B.V. 2011. All rights reserved.
16 of 22
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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
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 5 and 6
Table 5.
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 6.
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.
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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 7.
Abbreviations
Acronym
Description
CMOS
Complementary Metal-Oxide Semiconductor
DDC
Data Display Channel
I2C-bus
Inter-Integrated Circuit bus
I/O
Input/Output
IC
Integrated Circuit
PMBus
Power Management Bus
RC
Resistor-Capacitor network
SMBus
System Management Bus
15. References
PCA9525
Product data sheet
[1]
UM10204, I2C-bus specification and user manual — , Rev 03, 19 June 2007;
NXP B.V. www.nxp.com/documents/user_manual/UM10204.pdf
[2]
System Management Bus (SMBus) Specification — Version 2.0, August 3, 2000;
SBS Implementers Forum.
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 25 February 2011
© NXP B.V. 2011. All rights reserved.
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16. Revision history
Table 8.
Revision history
Document ID
Release date
Data sheet status
Change notice
Supersedes
PCA9525 v.1
20110225
Product data sheet
-
-
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Rev. 1 — 25 February 2011
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17. Legal information
17.1 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.
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.
Product specification — The information and data provided in a Product
data sheet shall define the specification of the product as agreed between
NXP Semiconductors and its customer, unless NXP Semiconductors and
customer have explicitly agreed otherwise in writing. In no event however,
shall an agreement be valid in which the NXP Semiconductors product is
deemed to offer functions and qualities beyond those described in the
Product data sheet.
17.3 Disclaimers
Limited warranty and liability — 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.
In no event shall NXP Semiconductors be liable for any indirect, incidental,
punitive, special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removal or
replacement of any products or rework charges) whether or not such
damages are based on tort (including negligence), warranty, breach of
contract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, NXP Semiconductors’ aggregate and cumulative liability towards
customer for the products described herein shall be limited in accordance
with the Terms and conditions of commercial sale of NXP Semiconductors.
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.
Customers are responsible for the design and operation of their applications
and products using NXP Semiconductors products, and NXP Semiconductors
accepts no liability for any assistance with applications or customer product
design. It is customer’s sole responsibility to determine whether the NXP
Semiconductors product is suitable and fit for the customer’s applications and
products planned, as well as for the planned application and use of
customer’s third party customer(s). Customers should provide appropriate
design and operating safeguards to minimize the risks associated with their
applications and products.
NXP Semiconductors does not accept any liability related to any default,
damage, costs or problem which is based on any weakness or default in the
customer’s applications or products, or the application or use by customer’s
third party customer(s). Customer is responsible for doing all necessary
testing for the customer’s applications and products using NXP
Semiconductors products in order to avoid a default of the applications and
the products or of the application or use by customer’s third party
customer(s). NXP does not accept any liability in this respect.
Limiting values — Stress above one or more limiting values (as defined in
the Absolute Maximum Ratings System of IEC 60134) will cause permanent
damage to the device. Limiting values are stress ratings only and (proper)
operation of the device at these or any other conditions above those given in
the Recommended operating conditions section (if present) or the
Characteristics sections of this document is not warranted. Constant or
repeated exposure to limiting values will permanently and irreversibly affect
the quality and reliability of the device.
Terms and conditions of commercial 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, unless otherwise
agreed in a valid written individual agreement. In case an individual
agreement is concluded only the terms and conditions of the respective
agreement shall apply. NXP Semiconductors hereby expressly objects to
applying the customer’s general terms and conditions with regard to the
purchase of NXP Semiconductors products by customer.
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.
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.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in life support, life-critical or
safety-critical systems or equipment, nor in applications where failure or
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.
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
© NXP B.V. 2011. All rights reserved.
20 of 22
PCA9525
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Simple 2-wire bus buffer
Non-automotive qualified products — Unless this data sheet expressly
states that this specific NXP Semiconductors product is automotive qualified,
the product is not suitable for automotive use. It is neither qualified nor tested
in accordance with automotive testing or application requirements. NXP
Semiconductors accepts no liability for inclusion and/or use of
non-automotive qualified products in automotive equipment or applications.
In the event that customer uses the product for design-in and use in
automotive applications to automotive specifications and standards, customer
(a) shall use the product without NXP Semiconductors’ warranty of the
product for such automotive applications, use and specifications, and (b)
whenever customer uses the product for automotive applications beyond
NXP Semiconductors’ specifications such use shall be solely at customer’s
own risk, and (c) customer fully indemnifies NXP Semiconductors for any
liability, damages or failed product claims resulting from customer design and
use of the product for automotive applications beyond NXP Semiconductors’
standard warranty and NXP Semiconductors’ product specifications.
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: [email protected]
PCA9525
Product data sheet
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Rev. 1 — 25 February 2011
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21 of 22
PCA9525
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Simple 2-wire bus buffer
19. Contents
1
2
3
4
5
6
6.1
6.2
7
7.1
7.2
7.3
7.4
7.5
8
9
9.1
9.2
10
10.1
11
12
13
13.1
13.2
13.3
13.4
14
15
16
17
17.1
17.2
17.3
17.4
18
19
General description . . . . . . . . . . . . . . . . . . . . . . 1
Features and benefits . . . . . . . . . . . . . . . . . . . . 1
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ordering information . . . . . . . . . . . . . . . . . . . . . 2
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pinning information . . . . . . . . . . . . . . . . . . . . . . 3
Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 3
Functional description . . . . . . . . . . . . . . . . . . . 3
VDD, VSS — supply pins . . . . . . . . . . . . . . . . . . 3
SCL_IN, SCL_OUT — clock signal inputs/
outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SDA_IN, SDA_OUT — data signal inputs/
outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Enable (EN) — activate buffer operations . . . . 4
Direction (DIR) — clock buffer direction
control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 5
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Bidirectional data buffer . . . . . . . . . . . . . . . . . . 7
Operating conditions. . . . . . . . . . . . . . . . . . . . . 9
Application information. . . . . . . . . . . . . . . . . . 10
Design considerations . . . . . . . . . . . . . . . . . . 10
Package outline . . . . . . . . . . . . . . . . . . . . . . . . 14
Handling information. . . . . . . . . . . . . . . . . . . . 16
Soldering of SMD packages . . . . . . . . . . . . . . 16
Introduction to soldering . . . . . . . . . . . . . . . . . 16
Wave and reflow soldering . . . . . . . . . . . . . . . 16
Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 17
Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 17
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 18
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Revision history . . . . . . . . . . . . . . . . . . . . . . . . 19
Legal information. . . . . . . . . . . . . . . . . . . . . . . 20
Data sheet status . . . . . . . . . . . . . . . . . . . . . . 20
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Contact information. . . . . . . . . . . . . . . . . . . . . 21
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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. 2011.
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: 25 February 2011
Document identifier: PCA9525