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.
NXP Semiconductors
PCA9508
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. Feature VCC(A) range (V) VCC(B) range (V) rise time accelerator idle/stop detect for hot-swap normal I/O static level offset
[1]
PCA9508 and I2C-bus repeaters comparison PCA9507 2.7 to 5.5 2.7 to 5.5 yes A side B side PCA9508 0.9 to 5.5 2.7 to 5.5 yes A side B side PCA9509 3.0 to 5.5 B side A side PCA9517A[1] 2.7 to 5.5 A side B side PCA9519 1.1 to VCC(B) − 1 3.0 to 5.5 B side A side 1.1 to VCC(B) − 1 0.9 to 5.5
PCA9517A is the high ESD (6.5 kV HBM and 550 V MM) drop-in replacement for PCA9517.
2. Features
I 2 channel, bidirectional buffer isolates capacitance and allows 400 pF on either side of the device I Supports offset-free hot-swap with IDLE/STOP detect circuitry I Voltage level translation from 0.9 V to 5.5 V and from 2.7 V to 5.5 V I Footprint and functional replacement for PCA9515, PCA9515A, PCA9517 and PCA9517A I I2C-bus and SMBus compatible I Active HIGH repeater enable input I Static level offset on B side I Open-drain input/outputs I Lock-up free operation I Supports arbitration and clock stretching across the repeater I Accommodates Standard-mode and Fast-mode I2C-bus devices and multiple masters I Powered-off high-impedance I2C-bus pins I A side operating supply voltage range of 0.9 V to 5.5 V I B side operating supply voltage range of 2.7 V to 5.5 V I 5 V tolerant I2C-bus and enable pins I 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). I ESD protection exceeds 6000 V HBM per JESD22-A114, 450 V MM per JESD22-A115, and 1000 V CDM per JESD22-C101 I Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA I Packages offered: SO8 and TSSOP8
PCA9508_1
© NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 01 — 28 April 2008
2 of 21
NXP Semiconductors
PCA9508
Hot swappable level translating I2C-bus repeater
3. Ordering information
Table 2. Ordering information Tamb = −40 °C to +85 °C. Type number PCA9508D PCA9508DP
[1]
Topside mark
Package Name Description plastic small outline package; 8 leads; body width 3.9 mm Version SOT96-1 SOT505-1
PCA9508 SO8 9508
TSSOP8[1] plastic thin shrink small outline package; 8 leads; body width 3 mm
Also known as MSOP8.
4. Functional diagram
VCC(A) VCC(B)
PCA9508
SDAA SDAB
SCLA
SCLB
CONNECT
0.55VCC/ 0.45VCC STOP BIT AND BUS IDLE
VCC(B)
pull-up resistor
0.5 µA
0.55VCC/ 0.45VCC UVLO EN 100 µs DELAY
20 pF
UVLO
RD S
QB
CONNECT
0.5 pF
002aac651
Fig 1.
Functional diagram of PCA9508
PCA9508_1
© NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 01 — 28 April 2008
3 of 21
NXP Semiconductors
PCA9508
Hot swappable level translating I2C-bus repeater
5. Pinning information
5.1 Pinning
VCC(A) SCLA SDAA GND
1 2
8 7
VCC(B) SCLB SDAB EN
VCC(A) SCLA SDAA GND
1 2 3 4
002aac653
8 7
VCC(B) SCLB SDAB EN
PCA9508D
3 4
002aac652
6 5
PCA9508DP
6 5
Fig 2.
Pin configuration for SO8
Fig 3.
Pin configuration for TSSOP8
5.2 Pin description
Table 3. Symbol VCC(A) SCLA SDAA GND EN SDAB SCLB VCC(B) Pin description Pin 1 2 3 4 5 6 7 8 Description A side supply voltage (0.9 V to 5.5 V) open-drain input/output serial clock A side bus open-drain input/output serial data A side bus supply ground (0 V) active HIGH repeater enable input with an internal pull-up (100 kΩ) open-drain input/output serial data B side bus open-drain input/output serial clock B side bus 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 © NXP B.V. 2008. All rights reserved.
Product data sheet
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NXP Semiconductors
PCA9508
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
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Product data sheet
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NXP Semiconductors
PCA9508
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
1.2 V
10 kΩ
10 kΩ
10 kΩ
10 kΩ
VCC(B) SDA SCL BUS MASTER 400 kHz EN bus B SDAB SCLB
VCC(A) SDAA SCLA SDA SCL
PCA9508
SLAVE 400 kHz
bus A
002aac654
Fig 4.
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
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Product data sheet
Rev. 01 — 28 April 2008
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NXP Semiconductors
PCA9508
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)
VCC(B)
10 kΩ
10 kΩ
10 kΩ
10 kΩ
VCC(A) SDA SCL BUS MASTER EN SDAA SCLA
VCC(B) SDAB SCLB SDA SCL
PCA9508
SLAVE 400 kHz
10 kΩ
10 kΩ
VCC(A) SDAA SCLA
VCC(B) SDAB SCLB SDA SCL
PCA9508
EN
SLAVE 400 kHz
10 kΩ
10 kΩ
VCC(A) SDAA SCLA
VCC(B) SDAB SCLB SDA SCL
PCA9508
EN
SLAVE 400 kHz
002aac655
Fig 5.
Typical star application
PCA9508_1
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Product data sheet
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PCA9508
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 SCL BUS MASTER hot-swap and offset free
SDAA SCLA
SDAB SCLB hot-swap and offset free
SDAA SCLA
SDAB SCLB hot-swap and offset free
SDAA SCLA
SDAB SCLB
SDA SCL
PCA9508
EN
PCA9508
EN
PCA9508
EN
SLAVE 400 kHz
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
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Product data sheet
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NXP Semiconductors
PCA9508
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 VCC(B) VCC(A) VI/O II Ptot Tstg Tamb Tj Parameter supply voltage port B supply voltage port A voltage on an input/output pin input current total power dissipation storage temperature ambient temperature junction temperature operating in free air Conditions 2.7 V to 5.5 V adjustable SDAA, SDAB, SCLA, SCLB, EN any pin Min −0.5 −0.5 −0.5 −55 −40 Max +7 +7 +7 50 100 +125 +85 +125 Unit V V V mA mW °C °C °C
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 Supplies VCC(B) VCC(A) ICC(A) ICCH supply voltage port B supply voltage port A supply current port A HIGH-level supply current pin VCC(A) both channels HIGH; VCC = 5.5 V; SDAn = SCLn = VCC both channels LOW; VCC = 5.5 V; one SDA and one SCL = GND; other SDA and SCL open VCC = 5.5 V; SDAn = SCLn = VCC
[1]
Parameter
Conditions
Min 2.7 0.9 -
Typ 1.5
Max 5.5 5.5 1 3
Unit V V mA mA
ICCL
LOW-level supply current
-
1.5
3
mA
ICC(A)c
contention port A supply current
-
1.5
3
mA
Input and output SDAB and SCLB VIH VIL VILc VIK ILI IIL VOL VOL−VILc HIGH-level input voltage LOW-level input voltage contention LOW-level input voltage input clamping voltage input leakage current LOW-level input current LOW-level output voltage II = −18 mA VI = 3.6 V SDA, SCL; VI = 0.2 V IOL = 100 µA or 6 mA
[2]
0.7VCC(B) −0.5 −0.5 0.47 0.4 0.52 -
5.5 −1.2 ±1 10 0.6 70
V V V µA µA V mV
+0.3VCC(B) V
difference between LOW-level guaranteed by design output and LOW-level input voltage contention HIGH-level output leakage current input/output capacitance VO = VCC VI = 3 V or 0 V; VCC = 3.3 V VI = 3 V or 0 V; VCC = 0 V
ILOH Cio
-
5.2 5.2
10 7 7
µA pF pF
9 of 21
PCA9508_1
© NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 01 — 28 April 2008
NXP Semiconductors
PCA9508
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 VIH VIL VIK ILI IIL VOL ILOH Cio Enable VIL VIH IIL(EN) ILI Ci
[1] [2]
Parameter HIGH-level input voltage LOW-level input voltage input clamping voltage input leakage current LOW-level input current LOW-level output voltage HIGH-level output leakage current input/output capacitance
Conditions
Min
Typ
Max
Unit V V µA µA V µA pF pF
Input and output SDAA and SCLA 0.6VCC(A) 0.5VCC(A) 5.5 −0.5 II = −18 mA VI = 3.6 V SDA, SCL; VI = 0.2 V IOL = 6 mA VO = VCC VI = 3 V or 0 V; VCC = 3.3 V VI = 3 V or 0 V; VCC = 0 V LOW-level input voltage HIGH-level input voltage LOW-level input current on pin EN input leakage current input capacitance
LOW-level supply voltage. 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.
0.1 5.2 5.2 −10 1.7
+0.4VCC(A) V −1.2 ±1 10 0.2 10 7 7
−0.5
+0.3VCC(B) V 5.5 −30 +1 7 V µA µA pF
0.7VCC(B) VI = 0.2 V, EN; VCC = 3.6 V VI = VCC VI = 3.0 V or 0 V −1 -
PCA9508_1
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PCA9508
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 tPLH tPHL Parameter LOW-to-HIGH propagation delay HIGH-to-LOW propagation delay Conditions B side to A side; Figure 11 B side to A side; Figure 9 VCC(A) < 3.0 V VCC(A) > 3.0 V tTLH tTHL LOW to HIGH output transition time A side; Figure 10 HIGH to LOW output transition time A side; Figure 10 VCC(A) < 2.7 V VCC(A) > 3.0 V tPLH tPHL tTLH tTHL tconnect LOW-to-HIGH propagation delay HIGH-to-LOW propagation delay A side to B side; Figure 10 A side to B side; Figure 10
[6] [6] [5] [5] [4]
Min 100 20 20 10 1 8 25 60 120 30 50 [10] [10]
Typ[3] 170 98 76 20 72 68 53 79 140 48 0.5 105 0.5 -
Max 250 118 164 30 83 137 110 230 170 90 200 -
Unit ns ns ns ns ns ns ns ns ns ns µs µs µs ns ns
LOW to HIGH output transition time B side; Figure 9 HIGH to LOW output transition time B side; Figure 9 connect time[7] time[8] B side to A side; Figure 12 B side to A side; Figure 13 A side to B side; Figure 14 EN HIGH before START condition EN HIGH after STOP condition
tidle(connect) connect idle tsu th
[1]
tstop(connect) connect stop time[9] set-up time hold time
100 100
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. Pull-up voltages are VCC(A) on the A side and VCC(B) on the B side. Typical values were measured with VCC(A) = 3.3 V at Tamb = 25 °C, unless otherwise noted. 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. Typical value measured with VCC(A) = 2.7 V at Tamb = 25 °C. 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. 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. Defined as the time required to connect from B side to A side, when B side and A side are idle. 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.
[2] [3] [4] [5] [6] [7] [8] [9]
[10] The enable pin, EN, should only change state when the global bus and the repeater port are in an idle state.
PCA9508_1
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Product data sheet
Rev. 01 — 28 April 2008
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PCA9508
Hot swappable level translating I2C-bus repeater
10.1 AC waveforms
3.0 V input 1.5 V tPHL 80 % output 1.5 V tPLH 80 % 0.1 V 1.2 V output VOL
002aad642
VCC(A) input 0.3VCC(A) tPHL 80 % 0.3VCC(A) tPLH 3.0 V 1.5 V 20 % tTHL 1.5 V 20 % 80 % tTLH
002aad643
0.6 V 20 % tTHL
0.6 V 20 %
tTLH
Fig 9.
Propagation delay and transition times; B side to A side
Fig 10. Propagation delay and transition times; A side to B side
input SDAB, SCLB 0.5 V
output SCLA, SDAA tPLH
50 % if VCC(A) is less than 2 V 1.5 V if VCC(A) is greater than 2 V
002aad641
Fig 11. Propagation delay; B side to A side
PCA9508_1
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Product data sheet
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PCA9508
Hot swappable level translating I2C-bus repeater
wait 200 µs EN VCC 0V tconnect VCC 0V move until SCLA goes LOW EN
wait 200 µs VCC 0V tconnect VCC 0V move until SDAA goes LOW
SDAA
SCLA
SCLB SDAB
SDAB SCLB
SCLA
SDAA
002aad716
Fig 12. tconnect timing
EN EN VCC 0V move until SDAA goes LOW
tidle(connect)
tidle(connect) VCC 0V move until SCLA goes LOW
SCLB
SDAB
SDAB SDAA
SCLB SCLA
SCLA
VCC 0V
SDAA
VCC 0V
002aad717
Fig 13. tidle(connect) timing
VCC 0V move until SCLB goes LOW tstop(connect) SDAA SCLB VCC 0V
002aad718
EN
SCLA
SDAB
Fig 14. tstop(connect) timing
PCA9508_1
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PCA9508
Hot swappable level translating I2C-bus repeater
11. Test information
VCC(B) VCC(A) PULSE GENERATOR VI DUT
RT CL
VCC(B)
RL
VO
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
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Product data sheet
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PCA9508
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 vMA
Z 8 5
Q A2 A1 pin 1 index θ Lp 1 e bp 4 wM L detail X (A 3) A
0
2.5 scale
5 mm
DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mm inches 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. OUTLINE VERSION SOT96-1 REFERENCES IEC 076E03 JEDEC MS-012 JEITA EUROPEAN PROJECTION A max. 1.75 0.069 A1 0.25 0.10 A2 1.45 1.25 A3 0.25 0.01 bp 0.49 0.36 c 0.25 0.19 D (1) 5.0 4.8 0.20 0.19 E (2) 4.0 3.8 0.16 0.15 e 1.27 0.05 HE 6.2 5.8 L 1.05 Lp 1.0 0.4 Q 0.7 0.6 v 0.25 0.01 w 0.25 0.01 y 0.1 0.004 Z (1) 0.7 0.3 0.028 0.012 θ
0.010 0.057 0.004 0.049
0.019 0.0100 0.014 0.0075
0.244 0.039 0.028 0.041 0.228 0.016 0.024
8o o 0
ISSUE DATE 99-12-27 03-02-18
Fig 16. Package outline SOT96-1 (SO8)
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TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm
SOT505-1
D
E
A
X
c y HE vMA
Z
8
5
A2 pin 1 index
A1
(A3)
A
θ Lp L
1
e bp
4
detail X wM
0
2.5 scale
5 mm
DIMENSIONS (mm are the original dimensions) UNIT mm A max. 1.1 A1 0.15 0.05 A2 0.95 0.80 A3 0.25 bp 0.45 0.25 c 0.28 0.15 D(1) 3.1 2.9 E(2) 3.1 2.9 e 0.65 HE 5.1 4.7 L 0.94 Lp 0.7 0.4 v 0.1 w 0.1 y 0.1 Z(1) 0.70 0.35 θ 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 SOT505-1 REFERENCES IEC JEDEC JEITA EUROPEAN PROJECTION ISSUE DATE 99-04-09 03-02-18
Fig 17. Package outline SOT505-1 (TSSOP8)
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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
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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 reflow temperature (°C) Volume (mm3) < 350 < 2.5 ≥ 2.5 Table 8. 235 220 Lead-free process (from J-STD-020C) Package reflow temperature (°C) Volume (mm3) < 350 < 1.6 1.6 to 2.5 > 2.5 260 260 250 350 to 2000 260 250 245 > 2000 260 245 245 ≥ 350 220 220
Package thickness (mm)
Package thickness (mm)
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.
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temperature
maximum peak temperature = MSL limit, damage level
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. Acronym CDM CMOS DUT ESD HBM I2C-bus I/O MM RC SMBus Abbreviations Description Charged-Device Model Complementary Metal-Oxide Semiconductor Device Under Test ElectroStatic Discharge Human Body Model Inter-Integrated Circuit bus Input/Output Machine Model Resistor-Capacitor network System Management Bus
15. Revision history
Table 10. Revision history Release date 20080428 Data sheet status Product data sheet Change notice Supersedes Document ID PCA9508_1
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16. Legal information
16.1 Data sheet status
Document status[1][2] Objective [short] data sheet Preliminary [short] data sheet Product [short] data sheet
[1] [2] [3]
Product status[3] Development Qualification Production
Definition This document contains data from the objective specification for product development. This document contains data from the preliminary specification. This document contains the product specification.
Please consult the most recently issued document before initiating or completing a design. The term ‘short data sheet’ is explained in section “Definitions”. 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.
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.
16.3 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
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
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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