Datasheet

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SCLOUT

SCLIN

GND

SDAOUT

SDAIN

READY

TCA4311A

www.ti.com

SCPS226A –JANUARY 2011–REVISED JULY 2012

HOT SWAPPABLE 2-WIRE BUS BUFFERS

Check for Samples: TCA4311A

FEATURES

• Operating Power-Supply Voltage Range of 2.7-

• Applications Include Hot Board Insertion and

V to 5.5-V Bus Extension

• Supports Bidirectional Data Transfer of I

C • Low I

Chip Disable of <1 μA

Bus Signals

• READY Open-Drain Output

• SDA and SCL Lines Are Buffered Which

• Supports Clock Stretching, Arbitration, and

Increases Fanout

Synchronization

• 1-V Precharge on All SDA and SCL Lines

• Powered-Off High-Impedance I

C Pins

Prevents Corruption During Live Board

• Open-Drain I

C Pins

Insertion and Removal From Backplane

• Latch-Up Performance Exceeds 100 mA Per

• SDA and SCL Input Lines Are Isolated From

JESD 78, Class II

Outputs

• ESD Protection Exceeds JESD 22

• Accommodates Standard Mode and Fast Mode

– 8000-V Human-Body Model (A114-A)

C Devices

– 200-V Machine Model (A115-A)

• Improved Noise Immunity

– 1000-V Charged-Device Model (C101)

D OR DGK PACKAGES

(TOP VIEW)

DESCRIPTION/ORDERING INFORMATION

The TCA4311A is a hot swappable I

C bus buffer that supports I/O card insertion into a live backplane without

corruption of the data and clock busses. 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. When the

connection is made, this device provides bidirectional buffering, keeping the backplane and card capacitances

isolated. During insertion, the SDA and SCL lines are precharged to 1 V to minimize the current required to

charge the parasitic capacitance of the chip.

When the I

C bus is idle, the TCA4311A can be put into shutdown mode by setting the EN pin low. When EN is

high, the TCA4311A resumes normal operation. It also includes an open drain READY output pin, which

indicates that the backplane and card sides are connected together. When READY is high, the SDAIN and

SCLIN are connected to SDAOUT and SCLOUT. When the two sides are disconnected, READY is low.

Both the backplane and card may be powered with supply voltages ranging from 2.7 V to 5.5 V, with no

restrictions on which supply voltage is higher.

The TCA4311A has standard open-drain I/Os. The size of the pullup resistors to the I/Os depends on the

system, but each side of this buffer must have a pullup resistor. The device is designed to work with Standard

Mode and Fast Mode I

C devices in addition to SMBus devices. Standard Mode I

C devices only specify 3 mA in

a generic I

C system where Standard Mode devices and multiple masters are possible. Under certain conditions,

high termination currents can be used.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2CompactPCI is a trademark of PCI Industrial Computer Manufacturers Group.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (25 pages)

PAGE 1
TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 HOT SWAPPABLE 2-WIRE BUS BUFFERS Check for Samples: TCA4311A FEATURES 1 • 2 • • • • • • Operating Power-Supply Voltage Range of 2.7V to 5.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com Table 1. ORDERING INFORMATION PACKAGE (1) TA SOIC – D –40°C to 85°C MSOP – DGK (1) (2) (2) ORDERABLE PART NUMBER TOP-SIDE MARKING Tube TCA4311AD PREVIEW Tape and reel TCA4311ADR PREVIEW Tape and reel TCA4311ADGKR 6KS Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 BLOCK DIAGRAM 2-Wire Bus Buffer and Hot Swap Controller 2 mA 2 mA Slew Rate Dectector Slew Rate Dectector 8 VCC Backplane-To-Card Connection SDAIN 6 CONNECT 74 SDAOUT CONNECT CONNECT ENABLE 100 k RCH1 100 k RCH3 1V Precharge 100 k RCH2 100 k RCH4 2 mA 2 mA Slew Rate Dectector Slew Rate Detector Backplane-To-Card Connection SCLIN 3 2 SCLOUT CONNECT CONNECT + – + + – – Stop Bit and Bus Idle 0.5 µA + 0.55 VCC/ 0.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com ABSOLUTE MAXIMUM RATINGS (1) over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT VCC Supply voltage range –0.5 7 V VI/O I2C bus voltage range (2) SDAIN, SCLIN, SDAOUT, SCLOUT –0.5 7 V VI Input voltage range (2) EN –0.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 ELECTRICAL CHARACTERISTICS over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Power Supply VCC Positive supply voltage ICC Supply current 2.7 ISD Supply current in shutdown VEN = 0 V mode VCC = 5.5 V, VSDAIN = VSCLIN = 0 V 5.5 5.1 7 V mA μA 0.1 Start-Up Circuitry VPRE Precharge voltage SDA, SCL floating 0.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com OPERATION Start-Up When the TCA4311A first receives power on its VCC pin, either during power-up or during live insertion, it starts in an undervoltage lockout (UVLO) state, ignoring any activity on the SDA and SCL pins until VCC rises above 2.5 V. During this time, the 1 V precharge circuitry is also active and forces 1 V through 100-kΩ nominal resistors to the SDA and SCL pins.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 10-kΩ pullup resistors and 100 pF equivalent capacitance on both sides of the part. By comparison with Figure 2, the VCC = 3.3 V curve shows that increasing the capacitance from 50 pF to 100 pF results in a tPHL increase from 55 ns to 75 ns. Larger output capacitances translate to longer delays (up to 150 ns).
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com Resistor Pull-Up Value Selection The system pullup resistors must be strong enough to provide a positive slew rate of 1.25 V/μs on the SDA and SCL pins, in order to activate the boost pullup currents during rising edges. Choose maximum resistor value R using the formula: R ≤ (VCC(MIN) – 0.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 TYPICAL PERFORMANCE CHARACTERISTICS 100 18 95 16 5V 2.7 V 90 14 85 12 IPULLUPAC (mA) tPHL 80 3.3 V 75 10 3V 8 70 6 65 2.5 V 5.5 V 2.7 V 4 60 2 55 0 50 –40 25 Temperature, TA (°C) 85 –50 –25 Figure 3. Input-Output tPLH vs Temperature 0 25 50 75 Figure 4.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 350 300 Offset Voltage (mV) 250 200 150 Vcc = 5V 100 Vcc = 3.3V 50 0 0 10,000 20,000 30,000 40,000 Resistance (Ω) Figure 5.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 PARAMETER MEASUREMENT INFORMATION VCC VCC Pulse Generator VI D.U.T. RL VO 10 kΩ CL RT 100 pF RL = Load resistor CL = Load capacitance includes jig and probe capacitance RT = Termination resistance should be equal to the output impedance Z0 of the pulse generators. Figure 6. Test Circuitry for Switching Times SDAn/SCLn ten ENABLE tdis tidle(READY) READY Figure 7.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com PARAMETER MEASUREMENT INFORMATION (continued) SCLIN, SDAIN SCLOUT, SDAOUT ten tidle(READY) ENABLE tstp(READY) READY Figure 9.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 APPLICATION INFORMATION Live Insertion and Capacitance Buffering Application Figure 10 through Figure 11 illustrate the usage of the TCA4311A in applications that take advantage of both its hot swap controlling and capacitance buffering features.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com Figure 11 shows the TCA4311A in a PCI application, where all of the pins have the same length. In this case, connect an RC series circuit on the I/O card between VCC and EN. An RC product of 10 ms provides a filter to prevent the TCA4311A from becoming activated until the transients associated with live insertion have settled. Backplane Backplane Connector I/O Periperal Card 1 VCC R1 10 k R2 10 k C1 0.
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TCA4311A www.ti.com SCPS226A – JANUARY 2011 – REVISED JULY 2012 2-Wire System 2 2-Wire System 1 VCC = 5 V VCC C1 0.01 µF R1 10 k R4 10 k C2 0.01 µF R5 10 k TCA4311 R2 R3 5.1 k 5.1 k R6 10 k R7 10 k TCA4311 VCC R8 10 k VCC EN SDAOUT SDAOUT EN SDA1 SDAIN SCLOUT SCLOUT SDAIN SDA1 SCL1 To Other System 1 Devices SCLIN READY READY SCLIN SCL1 To Other System 2 Devices GND GND Long Distance Bus Figure 12.
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TCA4311A SCPS226A – JANUARY 2011 – REVISED JULY 2012 www.ti.com REVISION HISTORY Changes from Original (January 2011) to Revision A • 16 Page Updated Input-output Offset Voltage vs Pullup Resistor graphic. ........................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 16-Aug-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TCA4311ADGKR VSSOP DGK 8 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 TCA4311ADR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 16-Aug-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TCA4311ADGKR VSSOP DGK 8 2500 358.0 335.0 35.0 TCA4311ADR SOIC D 8 2500 367.0 367.0 35.
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