PCA9517A Datasheet PDF - NXP Semiconductors
| Part Number | PCA9517A | |
| Description | Level translating I2C-bus repeater | |
| Manufacturers | NXP Semiconductors | |
| Logo |  |
|
|
There is a preview and PCA9517A download ( pdf file ) link at the bottom of this page. Total 22 Pages | ||
Preview 1 page No Preview Available !
PCA9517A
Level translating I2C-bus repeater
Rev. 4 — 9 May 2012
Product data sheet
1. General description
The PCA9517A is a CMOS integrated circuit that provides level shifting between low
voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) 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 PCA9517A enables the system designer to isolate two halves of a bus
for both voltage and capacitance. The SDA and SCL pins are overvoltage tolerant and are
high-impedance when the PCA9517A is unpowered.
The 2.7 V to 5.5 V bus port B drivers behave much like the drivers on the PCA9515A
device, while the adjustable voltage bus port A drivers drive more current and eliminate
the static offset voltage. This results in a LOW on the port B translating into a nearly 0 V
LOW on the port A which accommodates smaller voltage swings of lower voltage logic.
The static offset design of the port B PCA9517A I/O drivers prevent them from being
connected to another device that has rise time accelerator including the PCA9510,
PCA9511, PCA9512, PCA9513, PCA9514, PCA9515A, PCA9516A, PCA9517A (port B),
or PCA9518. Port A of two or more PCA9517As can be connected together, however, to
allow a star topography with port A on the common bus, and port A can be connected
directly to any other buffer with static or dynamic offset voltage. Multiple PCA9517As can
be connected in series, port A to port B, with no build-up in offset voltage with only time of
flight delays to consider.
The PCA9517A drivers are not enabled unless 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 port B 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
port B I/O is driven LOW internally, the LOW is not recognized as a LOW by the input.
This prevents a lock-up condition from occurring. The output pull-down on port A drives a
hard LOW and the input level is set at 0.3VCC(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. PCA9517 and PCA9517A comparison
Parameter
PCA9517[1]
electrostatic discharge, HBM
> 2 kV
PCA9517A[2]
> 5.5 kV
[1] PCA9517 will be discontinued in several years, so move to the PCA9517A for all new designs and system
updates.
[2] The PCA9517A is an improved hot swap and ESD version of the PCA9517, but otherwise operates
identically and should be used for all new designs and system updates.
|
| |
 
NXP Semiconductors
PCA9517A
Level translating I2C-bus repeater
6.1 Enable
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 and
enabling part way through a bus cycle could confuse the I2C-bus parts being enabled.
The enable pin should only change state when the global bus and the repeater port are in
an idle state to prevent system failures.
6.2 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
PCA9517A in a system or using the PCA9517A in conjunction with other bus buffers.
7. Application design-in information
A typical application is shown in Figure 5. 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
SDA
SCL
BUS
MASTER
400 kHz
10 kΩ
VCC(B)
SDAB
SCLB
10 kΩ
VCC(A)
SDAA
SCLA
PCA9517A
EN
10 kΩ
SDA
SCL
SLAVE
400 kHz
bus B
bus A
002aad468
Fig 5. Typical application
The PCA9517A 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.
PCA9517A
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 4 — 9 May 2012
© NXP B.V. 2012. All rights reserved.
5 of 22
Preview 5 Page |
Part DetailsOn this page, you can learn information such as the schematic, equivalent, pinout, replacement, circuit, and manual for PCA9517A electronic component. |
| Information | Total 22 Pages | |
| Link URL | [ Copy URL to Clipboard ] | |
| Product Image and Detail view |  1. - Level Translating I2C-bus Repeater [ Learn More ] | |
| Download | [ PCA9517A.PDF Datasheet ] | |
Share Link :
Electronic Components Distributor
|
An electronic components distributor is a company that sources, stocks, and sells electronic components to manufacturers, engineers, and hobbyists. |
| SparkFun Electronics | Allied Electronics | DigiKey Electronics | Arrow Electronics |
| Mouser Electronics | Adafruit | Newark | Chip One Stop |
Featured Datasheets
| Part Number | Description | MFRS |
| PCA9517 | The function is Level translating I2C-bus repeater. NXP Semiconductors | |
| PCA9517 | The function is Level-Translating I2C Bus Repeater (Rev. E). Texas Instruments |  |
| PCA9517 | The function is Level translating I2C-bus repeater. Philips |  |
Semiconductors commonly used in industry:
1N4148 |
BAW56 |
1N5400 |
NE555 | | ||
Quick jump to:
PCA9
1N4
2N2
2SA
2SC
74H
BC
HCF
IRF
KA | ||