|
|
PDF PCA9522 Data sheet ( Hoja de datos )
| Número de pieza | PCA9522 | |
| Descripción | Fast dual bidirectional bus buffer | |
| Fabricantes | NXP Semiconductors | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de PCA9522 (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
|
No Preview Available !
PCA9522
Fast dual bidirectional bus buffer with hot insertion logic
Rev. 1 — 28 September 2011
Product data sheet
1. General description
The PCA9522 is a monolithic bipolar integrated circuit for bus buffering in applications
including I2C-bus, SMBus, etc. It includes hot insertion logic for detecting stop and idle
conditions, making it ideal for live insertion into backplanes. The buffer extends the bus
load limit by buffering both the SCL and SDA lines. The PCA9522 is a drop-in
replacement for the IES5502, with only the maximum bus voltage reduced from 15 V to
10 V.
Hot insertion logic allows the IC to be plugged into live backplanes without causing data
corruption on the bus. The open-collector ready signal (RDY) indicates when the
connection has been made. Precharging of the backplane ports minimizes disruptions to
the bus during hot insertion.
The enable function allows sections of the bus to be isolated. Individual parts of the
system can be brought on-line successively. Bus level translation between a very wide
range of bus voltages, from 1.8 V to 10 V, is supported. These features provide enormous
flexibility in interfacing systems of different technologies, operating speeds and loads.
The unique operation of the PCA9522 provides one of the fastest response times of such
bidirectional buffers. It does this without the need for rise-time accelerators which,
combined with low noise margins, may cause glitches outside of the I2C-bus specification.
2. Features and benefits
Dual, bidirectional unity gain isolating buffer
Hot insertion logic prevents data and clock bus corruption for live backplane
applications
Pre-charge minimizes data corruption on live insertion
Supports I2C-bus (Standard-mode and Fast-mode), SMBus (standard and high power
modes) and PMBus
Open-collector ready output (RDY)
Fast switching times allow operation in excess of 1 MHz
Enable (EN) allows bus segments to be disconnected
Low current standby mode when not enabled
High-impedance ports when IC unpowered
6 mA (static) pull-down capability
Low noise susceptibility
Supports the connection of several buffers in series
Level shift bus voltages from 1.8 V to 10 V
1 page  
NXP Semiconductors
PCA9522
Fast dual bidirectional bus buffer with hot insertion logic
7.4 Ready (RDY) — buffer connected indicator
The ready output (RDY) indicates that the buffer has met its enable conditions, and that
communication will now occur. This is an open-collector transistor which is switched off
when ready, allowing the voltage at the pin to be pulled HIGH by a pull-up resistor.
7.5 Start-up
During power-up or live insertion into backplanes, the PCA9522 will start-up in an
UnderVoltage LockOut (UVLO) state where any activity on the input/output ports will be
ignored. This is to ensure that the PCA9522 does not try to operate when there is not
enough voltage on the supply.
During this time, the precharge circuit will charge all SCLB/SDAB backplane ports to
typically 0.92 V. This will minimize any voltage difference between the ports and hence
minimizes disruptions to the bus during hot insertion into backplanes.
When the supply increases above the UVLO state the PCA9522 will then monitor the bus
for either stop bit or bus idle condition. When a stop bit condition is detected and
SCLC/SDAC are both idle or when all SCL/SDA ports idle for a time period of typically
95 s, then the PCA9522 will activate the input-output connection circuitry. The precharge
circuitry is switched off. The voltage at the RDY pin is pulled HIGH by an external pull-up
resistor to indicate the input/output connection has been made.
8. Limiting values
Table 3. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter
Conditions
Min
VCC supply voltage
Vn voltage on any other pin SCLB, SCLC,
SDAB, SDAC
[1] 0.3
[1] 0.3
VI(EN)
IIO
Ptot
Tstg
Tamb
input voltage on pin EN
input/output current
total power dissipation
storage temperature
ambient temperature
DC; any pin
operating
[1] 0.3
-
-
55
40
[1] Voltages are specified with respect to pin 4 (GND).
Max
+7
+12
+12
20
300
+125
+85
Unit
V
V
V
mA
mW
C
C
PCA9522
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 28 September 2011
© NXP B.V. 2011. All rights reserved.
5 of 20
5 Page 
NXP Semiconductors
PCA9522
Fast dual bidirectional bus buffer with hot insertion logic
10.2 Input to output offset voltage calculation
The offset voltage between the side acting as the output (Sxxx(out)) and the side acting as
the input (Sxxx(in)) of the PCA9522 can be calculated using the relationship given in
Equation 1:
Voffset
=
Vi + 50
m
V
+
V----B-R---U---S-
11
(1)
This calculation is valid for VSxxx(in) 200 mV, as below this point the saturation voltage of
the open-collector output drive transistor will begin to affect the characteristic. Input and
output voltages are shown in millivolts, VBUS (the supply voltage to the bus) is in volts, and
R is in ohms.
An example calculation for VBUS = 3.3 V, VSxxC = 200 mV, the resistance R pulling up
SxxB is 2 k, then the voltage on SxxB is typically:
VSxxB
=
200
mV + 50
mV
+
2---30---.-03--0--
11
=
268
mV
(2)
This can be compared with the offset characteristic shown in Figure 5.
PCA9522
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 28 September 2011
© NXP B.V. 2011. All rights reserved.
11 of 20
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet PCA9522.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| PCA9521 | Fast dual bidirectional bus buffer | NXP Semiconductors |
| PCA9522 | Fast dual bidirectional bus buffer | NXP Semiconductors |
| PCA9525 | Simple 2-wire bus buffer | NXP Semiconductors |
| PCA9527 | 3-channel bidirectional bus extender | NXP Semiconductors |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |