Datasheet

ManualsBrandsNXP SEMICONDUCTORS ManualsInterface ICsInterface IC - buffer amplifiers, repeaters I²C 1 MHz TSSOP 16

1. General description

The PCA9646 is a monolithic CMOS integrated circuit for 2-wire bus buffering and

switching in applications including I

C-bus, SMBus, PMBus, and other systems based on

similar principles.

Each of the four outputs may be independently enabled in any combination as determined

by the contents of the programmable control register. Each I/O is impedance isolated from

all others, thus allowing a total of five branches of 2-wire bus with the maximum specified

load (e.g., 5  400 pF for Fm+ I

C-bus at 1 MHz, or 5  4 nF at lower frequencies)

(Ref. 1

). More than one PCA9646 may be used in series, providing a substantial fan-out

capability.

As per the PCA9525 and PCA9605 simple bus buffers, the PCA9646 includes a

unidirectional buffer for the clock signal, and a bidirectional buffer for the data signal. The

direction of the clock signal may also be set by the contents of the programmable control

The PCA9646 has excellent application to 2-wire bus address expansion and increasing

of maximum load capacitance. Very large LED displays are a perfect example.

2. Features and benefits

 Drop-in pin compatible with PCA9546A, etc.

 Each I/O is impedance isolated from all others allowing maximum capacitance on all

branches

 30 mA static sink capability on all ports

 Works with I

C-bus (Standard-mode, Fast-mode, and Fast-mode Plus (Fm+)),

SMBus (standard and high power mode), and PMBus

 Fast switching times allow operation in excess of 1 MHz

 Allows driving of large loads (e.g., 5  4nF)

 Hysteresis on I/O increases noise immunity

 Operating voltages from 2.7 V to 5.5 V

 Uncomplicated characteristics suitable for quick implementation in most common

2-wire bus applications

3. Applications

 Large arrays of I

C-bus components, e.g., LED displays

 Power management systems

 Game consoles, computers, RAID systems

PCA9646

Buffered 4-channel 2-wire bus switch

Rev. 1 — 1 March 2011 Product data sheet

Summary of content (22 pages)

PAGE 1
PCA9646 Buffered 4-channel 2-wire bus switch Rev. 1 — 1 March 2011 Product data sheet 1. General description The PCA9646 is a monolithic CMOS integrated circuit for 2-wire bus buffering and switching in applications including I2C-bus, SMBus, PMBus, and other systems based on similar principles. Each of the four outputs may be independently enabled in any combination as determined by the contents of the programmable control register.
PAGE 2
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 4. Ordering information Table 1. Ordering information Type number Topside mark Package Name Description Version PCA9646D PCA9646 SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1 PCA9646PW PCA9646 TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1 5. Block diagram 2.7 V to 5.
PAGE 3
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 6. Pinning information 6.1 Pinning A0 1 16 VDD A1 2 15 SDA RESET 3 14 SCL SD0 4 13 A2 PCA9646D SC0 5 12 SC3 SD1 6 11 SD3 SC1 7 VSS 8 A0 1 16 VDD A1 2 15 SDA RESET 3 14 SCL SD0 4 SC0 5 SD1 6 11 SD3 SC1 7 10 SC2 VSS 8 10 SC2 9 SD2 002aaf364 Fig 2. Pin configuration for SO16 PCA9646PW 13 A2 12 SC3 9 SD2 002aaf366 Fig 3. Pin configuration for TSSOP16 6.2 Pin description Table 2.
PAGE 4
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 7. Functional description Refer to Figure 1 “Simplified block diagram of PCA9646”. 7.1 VDD, VSS — DC supply pins The power supply voltage for the PCA9646 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 are a percentage of the IC’s power supply, hence noise margin considerations should be taken into account when selecting an operating voltage. 7.
PAGE 5
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 7.5 RESET — reset IC to default state The active LOW RESET input is used to disable the buffer, and reset it to its default state. The IC should only be disabled when the bus is idle to avoid truncation of commands which may confuse other devices on the bus. The RESET signal will clear the contents of the Control register, which has the effect of disabling all output lines SC[0:3] and SD[0:3].
PAGE 6
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch A LOW or ‘zero’ bit (B[3:0]) indicates that the respective channel (SC[3:0], SD[3:0]) is disabled. The default reset condition of the register is all zeros, all channels disabled, forward direction. A HIGH or ‘one’ bit indicates the respective channel is enabled. Example: B3 = 1, B2 = 0, B1 = 1, B0 = 0 means channel 3 (SC3/SD3) and channel 1 (SC1/SD1) are enabled, and channel 2 (SC2/SD2) and channel 0 (SC0/SD0) are disabled.
PAGE 7
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 9. 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 VI/O voltage on an input/output pin pins SDx, SCx [1] VSS  0.5 +7 V VI input voltage RESET pin [1] VSS  0.5 VDD + 0.5 V address pins A2, A1, A0 [1] VSS  0.5 VDD + 0.
PAGE 8
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 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 VIH HIGH-level input voltage VDD = 2.7 V 2.0 - - V VDD = 5.5 V 4.8 - - V VIL LOW-level input voltage VDD = 2.7 V - - 650 mV VDD = 5.5 V - - 900 mV VDD = 2.7 V 100 - - mV VDD = 5.
PAGE 9
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 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 9. Typical input levels versus supply voltage 002aaf372 250 VOL (mV) 200 Fig 10. Typical VIH  VIL hysteresis versus supply voltage 002aaf373 400 VOL (mV) 300 VDD = 2.7 V 150 200 100 5.5 V VDD = 5.5 V 100 50 2.
PAGE 10
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 11. Application information Figure 13 shows a typical data transfer through the PCA9646. The PCA9646 has excellent application to extending loads and expanding the address space of slave devices. Rise times are determined simply by the side of the buffer with the slowest RC time constant.
PAGE 11
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 3.3 V R2 1.1 kΩ R1 1.1 kΩ VDD R7 1.1 kΩ VDD R8 1.1 kΩ SCL SCL SC0 SC0 SDA SDA SD0 SD0 U5 R3 1.1 kΩ U4 R4 1.1 kΩ SC2 SC2 SD2 SD2 400 pF load at 1 MHz or 4 nF load at 100 kHz R5 1.1 kΩ SC3 SC3 SD3 SD3 400 pF load at 1 MHz or 4 nF load at 100 kHz VDD SCL SLAVE U6 400 pF load at 1 MHz or 4 nF load at 100 kHz R9 1.1 kΩ R6 1.1 kΩ SDA VDD SCL SLAVE R10 1.
PAGE 12
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch Figure 16 shows how PCA9646 can be used to combine or extend existing long cable systems using P82B715 I2C-bus extenders when they have reached their maximum capacitance limit. P82B715 alone provides a ‘10 impedance transformation’ (Ref. 2) but no isolation of the loadings on either side. P82B715 systems have a finite capacitance limit and its system calculations can be relatively complex.
PAGE 13
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch The PCA9646 may also be driven in series. Figure 17 shows this configuration. In this scenario, each of the four outputs of the first device (U2) has six more PCA9646’s connected to it. Each of those six devices has four outputs, thus giving 4  7  4 = 112 outputs. If the RESET pin on U2 was also driven from the master, it would be possible to reproduce this entire structure multiple times, giving a truly massive address space capability.
PAGE 14
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 12. Package outline SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1 D E A X c y HE v M A Z 16 9 Q A2 A (A 3) A1 pin 1 index θ Lp 1 L 8 e 0 detail X w M bp 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 (1) 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 10.0 9.8 4.
PAGE 15
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch TSSOP16: plastic thin shrink small outline package; 16 leads; body width 4.4 mm SOT403-1 E D A X c y HE v M A Z 9 16 Q (A 3) A2 A A1 pin 1 index θ Lp L 1 8 e detail X 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 Q v w y Z (1) θ mm 1.1 0.15 0.05 0.95 0.80 0.25 0.30 0.19 0.2 0.1 5.1 4.9 4.5 4.3 0.65 6.6 6.2 1 0.75 0.
PAGE 16
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 13. 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. 14. Soldering of SMD packages This text provides a very brief insight into a complex technology.
PAGE 17
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 14.3 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 14.
PAGE 18
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch maximum peak temperature = MSL limit, damage level temperature minimum peak temperature = minimum soldering temperature peak temperature time 001aac844 MSL: Moisture Sensitivity Level Fig 20. Temperature profiles for large and small components For further information on temperature profiles, refer to Application Note AN10365 “Surface mount reflow soldering description”. 15. Abbreviations Table 7.
PAGE 19
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 17. Revision history Table 8. Revision history Document ID Release date Data sheet status Change notice Supersedes PCA9646 v.1 20110301 Product data sheet - - PCA9646 Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 1 — 1 March 2011 © NXP B.V. 2011. All rights reserved.
PAGE 20
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 18. Legal information 18.1 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.
PAGE 21
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 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.
PAGE 22
PCA9646 NXP Semiconductors Buffered 4-channel 2-wire bus switch 20. Contents 1 2 3 4 5 6 6.1 6.2 7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 8 9 10 11 12 13 14 14.1 14.2 14.3 14.4 15 16 17 18 18.1 18.2 18.3 18.4 19 20 General description . . . . . . . . . . . . . . . . . . . . . . 1 Features and benefits . . . . . . . . . . . . . . . . . . . . 1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Ordering information . . . . . . . . . . . . . . . . . . . . . 2 Block diagram . . . . . . . . . .