TI TB5T1

TB5T1
www.ti.com
SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
DUAL DIFFERENTIAL PECL DRIVER/RECEIVER
FEATURES
•
•
•
•
Functional Replacement for the Agere BTF1A
Driver Features
– Third-State Logic Low Output
– ESD Protection HBM > 3 kV, CDM > 2 kV
– No Line Loading when Vcc = 0
– Capable of Driving 50-Ω loads
– 2.0-ns Maximum Propagation Delay
– 0.2-ns Output Skew (typical)
Receiver Features
– High-Input Impedance Approximately 8 kΩ
– 4.0-ns Maximum Propagation Delay
– 50-mV Hysteresis
– Slew Rate Limited (1 ns min 80% to 20%)
– ESD Protection HBM > 3 kV, CDM > 2 kV
– -1.1-V to 7.1-V Input Voltage Range
Common Device Features
– Common Enable for Each Driver/Receiver
Pair
– Operating Temperature Range: -40°C to
85°C
– Single 5.0 V ± 10% Supply
– Available in Gull-Wing SOIC (JEDEC
MS-013, DW) and SOIC (D) Package
In circuits with termination resistors, the line remains
impedance- matched when the circuit is powered
down. The driver does not load the line when it is
powered down.
All devices are characterized for operation from -40°C
to 85°C.
The logic inputs of this device include internal pull-up
resistors of approximately 40 kΩ that are connected
to VCC to ensure a logical high level input if the inputs
are open circuited.
PIN ASSIGNMENTS
DW AND D PACKAGE
(TOP VIEW)
RO1
1
16
RI1
DI1
2
15
RI1
VCC
3
14
DO1
ED
4
13
DO1
ER
5
12
DO2
GND
6
11
DO2
DI2
7
10
RI2
RO2
8
9
RI2
FUNCTIONAL BLOCK DIAGRAM
DO1
DO2
DI2
DESCRIPTION
ED
The TB5T1 device is a dual differential driver/receiver
circuit that transmits and receives digital data over
balanced transmission lines. The dual drivers translate input TTL logic levels to differential pseudo-ECL
output levels. The dual receivers convert differential-input logic levels to TTL output levels. Each driver
or receiver pair has its own common enable control
allowing serial data and a control clock to be
transmitted and received on a single integrated circuit. The TB5T1 requires the customer to supply
termination resistors on the circuit board.
RI1
The power-down loading characteristics of the receiver input circuit are approximately 8 kΩ relative to
the power supplies; hence, it does not load the
transmission line when the circuit is powered down.
DO1
DI1
DO2
RO1
RI1
RI2
RO2
RI2
ER
ENABLE TRUTH TABLE
ED
ER
0
0
1
0
0
1
1
1
D1
D2
R1
R2
Active
Active
Active
Active
Disabled
Disabled
Active
Active
Active
Active
Disabled
Disabled
Disabled
Disabled
Disabled
Disabled
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.
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.
Copyright © 2003–2004, Texas Instruments Incorporated
TB5T1
www.ti.com
SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
These devices have limited built-in ESD protection. The leads should be shorted together or the device
placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
PART NUMBER
PART MARKING
PACKAGE
LEAD FINISH
STATUS
TB5T1DW
TB5T1
Gull-Wing SOIC
NiPdAu
Production
TB5T1D
TB5T1
SOIC
NiPdAu
Production
TB5T1LDW
TB5T1L
Gull-Wing SOIC
SnPb
Production
TB5T1LD
TB5T1L
SOIC
SnPb
Production
POWER DISSIPATION RATINGS
PACKAGE
D
DW
(1)
(2)
(3)
CIRCUIT
BOARD MODEL
DERATING FACTOR (1)
TA≥ 25°C
POWER RATING
TA = 85°C
132.8°C/W
7.5 mW/°C
301 mW
85.8°C/W
11.7 mW/°C
466 mW
814 mW
122.7°C/W
8.2 mW/°C
325 mW
1200 mW
83.1°C/W
12 mW/°C
481 mW
POWER RATING
TA≤ 25°C
THERMAL RESISTANCE, JUNCTIONTO-AMBIENT WITH NO AIR FLOW
Low-K (2)
752 mW
High-K (3)
1160 mW
Low-K (2)
High-K (3)
This is the inverse of the junction-to-ambient thermal resistance when board-mounted with no airflow.
In accordance with the low-K thermal metric definitions of EIA/JESD51-3.
In accordance with the high-K thermal metric definitions of EIA/JESD51-7.
THERMAL CHARACTERISTICS
PARAMETER
2
PACKAGE
VALUE
UNIT
D
48.4
°C/W
θJB
Junction-to-board
thermal resistance
DW
55.2
°C/W
θJC
Junction-to-case
thermal resistance
D
45.1
°C/W
DW
48.1
°C/W
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted (1)
UNIT
Supply voltage, VCC
0 V to 6 V
Magnitude of differential bus (input) voltage, |VRI1 - VRI1|, |VRI2 - VRI2|
ESD
Human Body Model
(2)
Charged-Device Model
(3)
8.4 V
All pins
±3 kV
All pins
±2 kV
Continuous power dissipation
See Dissipation Rating Table
Storage temperature, Tstg
(1)
(2)
(3)
-65°C to 150°C
Stresses beyond those listed under "absolute maximum ratings” may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
Tested in accordance with JEDEC Standard 22, Test Method A114-A.
Tested in accordance with JEDEC Standard 22, Test Method C101.
RECOMMENDED OPERATING CONDITIONS
Supply voltage, VCC
MIN
NOM
MAX
4.5
5
UNIT
5.5
V
-1.2 (1)
7.2
V
Magnitude of differential input voltage, |VRI1 - VRI1|, |VRI2 - VRI2|
0.1
6
V
Operating free-air temperature, TA
-40
85
°C
Bus pin input voltage, VRI1, VRI1, VRI2, or VRI2
(1)
The algebraic convention, in which the least positive (most negative) limit is designated as minimum is used in this data sheet, unless
otherwise noted.
ELECTRICAL CHARACTERISTICS
over operating free-air temperature range unless otherwise noted
PARAMETER
ICC
Supply current
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Outputs disabled
40
mA
Outputs enabled
40
mA
3
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
THIRD STATE
A TB5T1 driver produces pseudo-ECL levels and has a third state mode, which is different from a conventional
TTL device. When a TB5T1 driver is placed in the third state, the base of the output transistors are pulled low,
bringing the outputs below the active-low level of standard PECL devices. (For example: The TB5T1 low output
level is typically 2.7 V, while the third state noninverting output level is typically 1.2 V.) In a bidirectional,
multipoint bus application, the driver of one device, which is in its third state, can be back driven by another
driver on the bus whose voltage in the low state is lower than the 3-stated device. This could be due to
differences between individual driver's power supplies. In this case, the device in the third state controls the line,
thus clamping the line and reducing the signal swing. If the difference between the driver power supplies is small,
this consideration can be ignored. Again using the TB5T1 driver as an example, a typical supply voltage
difference between separate drivers of > 2 V can exist without significantly affecting the amplitude of the signal.
DRIVER ELECTRICAL CHARACTERISTICS
over operating free-air temperature range unless otherwise noted
PARAMETER
TEST CONDITIONS
voltage (1)
VOH
Output high
VOL
Output low voltage (1)
VOD
Differential output voltage, |VOH - VOL|
voltage (1)
MIN
TYP
MAX
UNIT
VCC - 1.8
VCC - 1.3
VCC - 0.8
V
VOH - 1.4
VOH - 1.2
VOH - 0.7
V
0.7
1.1
1.4
V
VOH
Output high
VOL
Output low voltage (1)
VOD
Differential output voltage, |VOH - VOL|
VOC(PP)
Peak-to-peak common-mode output voltage
VOZH
Third state output high voltage (1)
VOZD
Third state diferential output voltage (1) VDOn - VDOn
VIL
Input low voltage (3)
VCC = 5.5 V
VIH
Input high voltage
VCC = 4.5 V
VIK
Input clamp voltage
VCC = 4.5 V, II = -5 mA
-1 (2)
V
VCC = 5.5 V, VO = 0 V
-250 (2)
mA
VCC = 5.5 V, VOD = 0 V
±10 (2)
mA
TA = 0°C to 85°C
DO1, DO2
VCC - 1.8
VCC - 1.3
VCC - 0.8
V
VOH - 1.4
VOH - 1.1
VOH - 0.5
V
0.5
1.1
1.4
V
mV
CL= 5 pF, See Figure 7
VCC = 4.5 V
230
600
1.4
1.8
2.2
-0.47 (2)
-0.6
0.8
2
V
V
V
IOS
Short-circuit output current (4)
IIL
Input low current
VCC = 5.5 V, VI = 0.4 V
-400 (2)
µA
IIH
Input high current
VCC = 5.5 V, VI = 2.7 V
20
µA
IIH
Input reverse current
VCC = 5.5 V, VI = 5.5 V
100
µA
CIN
Input Capacitance
(1)
(2)
(3)
(4)
4
5
pF
Values are with terminations as per Figure 6.
This parameter is listed using a magnitude and polarity/direction convention, rather than an algebraic convention, to match the original
Agere data sheet.
The input levels and difference voltage provide no noise immunity and should be tested only in a static, noise-free environment.
Test must be performed one lead at a time to prevent damage to the device. No test circuit attached.
TB5T1
www.ti.com
SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
RECEIVER ELECTRICAL CHARACTERISTICS
over operating free-air temperature range unless otherwise noted
PARAMETER
TEST CONDITIONS
VOL
Output low voltage
VCC = 4.5 V, IOL = 8.0 mA
VOH
Output high voltage
VCC = 4.5 V, IOH = -400 µA
VIL
Enable input low voltage (1)
VCC= 5.5 V
VIH
Enable input high voltage (1)
VCC = 4.5 V
MIN
TYP
MAX
UNIT
0.4
2.4
V
V
0.8
2
V
V
VIK
Enable input clamp voltage
VCC = 4.5 V, II = -5 mA
-1 (2)
VTH+
Positive-going differential input threshold voltage (1)
|VRin - VRin|
n = 1 or 2
100
mV
VTH-
Negative-going differential input threshold voltage (1)
|VRin - VRin|
n = 1 or 2
-100 (2)
mV
VHYST
Differential input threshold voltage hysteresis
(VTH+- VTH-)
IOZL
Off-state output low current (high Z)
VCC = 5.5 V, VO = 0.4 V
-20 (2)
µA
IOZH
Off-state output high current (high Z)
VCC = 5.5 V, VO = 2.4 V
20
µA
mA
current (3)
50
V
mV
IOS
Short circuit output
VCC = 5.5 V
-100 (2)
IIL
Enable input low current
VCC = 5.5 V, VIN = 0.4 V
-400 (2)
µA
IIH
Enable input high current
VCC = 5.5 V, VIN = 2.7 V
20
µA
IIH
Enable input reverse current
VCC = 5.5 V, VIN = 5.5 V
100
µA
-2 (2)
mA
1
mA
IIL
Differential input low current
VCC = 5.5V, VIN = -1.2 V
IIH
Differential input high current
VCC = 5.5V, VIN = 7.2 V
RO
Output resistance
(1)
(2)
(3)
Ω
20
The input levels and difference voltage provide no noise immunity and should be tested only in a static, noise-free environment.
This parameter is listed using a magnitude and polarity/direction convention, rather than an algebraic convention, to match the original
Agere data sheet.
Test must be performed one lead at a time to prevent damage to the device.
DRIVER SWITCHING CHARACTERISTICS
over operating free-air temperature range unless otherwise noted
PARAMETER
tP1
Propagation delay time, input high to output (1)
tP2
Propagation delay time, input low to output (1)
∆tP
Capacitive delay
tPHZ
Propagation delay time,
high-level-to-high-impedance output
tPLZ
TEST CONDITIONS
MIN
TYP
MAX
UNIT
1.2
2
ns
1.2
2
ns
0.01
0.03
8
12
ns
Propagation delay time,
low-level-to-high-impedance output
7
12
ns
tPZH
Propagation delay time,
high-impedance-to-high-level output
4
12
ns
tPZL
Propagation delay time,
high-impedance-to-low-level output
5
12
ns
tskew1
Output skew, |tP1 - tP2|
0.15
0.3
ns
tskew2
Output skew, |tPHH - tPHL|, |tPLH - tPLL|
0.15
1.1
ns
skew (2)
tskew(pp)
Part-to-part
∆tskew
Output skew, difference between drivers
tTLH
Rise time (20%-80%)
tTHL
Fall time (80%-20%)
(1)
(2)
CL= 5 pF, See Figure 2 and Figure 6
CL = 5 pF, See Figure 3 and Figure 6
CL= 5 pF, See Figure 2 andFigure 6
0.1
ns/pF
1
ns
0.3
ns
0.7
2
ns
0.7
2
ns
Parameters tP1 and tP2 are measured from the 1.5 V point of the input to the crossover point of the outputs (see Figure 2).
tskew(pp) is the magnitude of the difference in propagation delay times between any specified outputs of two devices when both devices
operate with the same supply voltage, at the same temperature, and have identical packages and test circuits.
5
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
RECEIVER SWITCHING CHARACTERISTICS
over operating free-air temperature range unless otherwise noted
PARAMETER
TEST CONDITIONS
tPLH
Propagation delay time, low-to-high-level output
tPHL
Propagation delay time, high-to-low-level output
tPLH
Propagation delay time, low-to-high-level output
tPHL
Propagation delay time, high-to-low-level output
tPHZ
Propagation delay time,
high-level-to-high-impedance output
Propagation delay time,
low-level-to-high-impedance output
tPLZ
tskew1
∆tskew1p-p
skew (2)
Same part output waveform
tPZH
Propagation delay time,
high-impedance-to-high-level output
skew (2)
tPZL
Propagation delay time,
high-impedance-to-low-level output
tTLH
Rise time (20%—80%)
tTHL
Fall time (80%—20%)
MAX
4
2.5
4
3
5.5
3
5.5
6
12
ns
6
12
ns
0.7
ns
4
ns
1.4
ns
CL = 10 pF, TA = -40°C to 85°C, See
Figure 4 and Figure 8
1.5
ns
CL = 10 pF, See Figure 4 and Figure 8
0.3
ns
3
12
ns
4
12
ns
1
4
ns
1
4
ns
CL = 15 pF, See Figure 4 and Figure 8
ns
ns
CL = 5 pF, See Figure 5 and Figure 9
CL = 10 pF, TA = 75°C, See Figure 4
and Figure 8
0.8
CL = 10 pF, See Figure 5 and Figure 8
CL = 10 pF, See Figure 5 and Figure 8
The propagation delay values with a 0 pF load are based on design and simulation.
Output waveform skews are when devices operate with the same supply voltage, same temperature, have the same packages and the
same test circuits.
t pd − Propagation Delay Time − ns
10
8
tPLH
6
tPHL
4
2
0
0
50
100
150
CL − Load Capacitance − pF
200
NOTE: This graph is included as an aid to the system designers. Total circuit delay varies with load capacitance. The total
delay is the sum of the delay due to external capacitance and the intrinsic delay of the device. Intrinsic delay is listed
in the table above as the 0 pF load condition. The incremental increase in delay between the 0 pF load condition and
the actual total load capacitance represents the extrinsic, or external delay contributed by the load.
Figure 1. Typical Propagation Delay vs Load Capacitance at 25°C
6
UNIT
2.5
CL = 0 pF (1), See Figure 4 and Figure 8
Load capacitance (CL) = 150 pF, See
Figure 4 and Figure 8
∆tskew
(1)
(2)
TYP
Load capacitance (CL) = 10 pF, See
Figure 4 and Figure 8
Pulse width distortion, |tPHL - tPLH|
Part-to-part output waveform
MIN
TB5T1
www.ti.com
SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
PARAMETER MEASUREMENT INFORMATION
2.4 V
1.5 V
INPUT
0.4 V
t
t P2
P1
VOH
OUTPUTS
VOL
tPHH
t PLL
VOH
(V OH+ VOL)/2
OUTPUT
VOL
t PLH
t PHL
VOH
(V OH+ VOL)/2
OUTPUT
VOL
80%
VOH
80%
OUTPUT
20%
20%
tTLH
VOL
tTHL
Figure 2. Driver Propagation Delay TImes
2.4 V
ED
1.5 V
0.4 V
tPHZ
tPZH
VOH
VOL +0.2 V
VOL
OUTPUT
VOL −0.1 V
OUTPUT −0.47 V
tPLZ
tPZL
VOL
VOL −0.1 V
OUTPUT
A.
NOTE: In the third state, OUTPUT is 0.47 V (minimum) more negative than OUTPUT.
Figure 3. Driver Enable and Disable Delay Times for a High Input
7
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
PARAMETER MEASUREMENT INFORMATION (continued)
3.7 V
INPUT
3.2 V
2.7 V
INPUT
t PLH
t PHL
OUTPUT
80%
V OH
80%
1.5 V
20%
20%
t THL
VOL
t TLH
Figure 4. Receiver Propagation Delay Times
2.4 V
ER
1.5 V
0.4 V
t PZH
t PHZ
t PLZ
t PZL
V OH
OUTPUT
V OL
0.2 V
0.2 V
0.2 V
0.2 V
Figure 5. Receiver Enable and Disable Timing
Parametric values specified under the Electrical Characteristics and Timing Characteristics sections for the data
transmission driver devices are measured with the following output load circuits.
100 CL
200 200 CL
CL includes test−fixture and probe capacitance.
Figure 6. Driver Test Circuit
8
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
PARAMETER MEASUREMENT INFORMATION (continued)
VOC
50 CL
200 VOH
50 CP =
OUTPUTS
VOL
200 CL
2 pF
VOC
CL includes test−fixture and probe capacitance.
A.
VOC(PP)
NOTE: All input pulses are supplied by a generator having the following characteristics: tr or tf = 1 ns, pulse repetition
rate (PRR) = 0.25 Mbps, pulse width = 500 ± 10 ns. CP includes the instrumentation and fixture capacitance within
0,06 m of the D.U.T. The measurement of VOS(PP) is made on test equipment with a -3 dB bandwidth of at least 1
GHz.
Figure 7. Test Circuit and Definitions for the Driver Common-Mode Output Voltage
5V
TO OUTPUT
OF DEVICE
UNDER TEST
2k
CL
5k
DIODES TYPE
458E, 1N4148,
OR EQUIVALENT
Figure 8. Receiver Propagation Delay Time and Enable Time (tPZH, tPZL) Test Circuit
TO OUTPUT
OF DEVICE
UNDER TEST
500 1.5 V
CL
Figure 9. Receiver Disable Time (tPHZ, tPLZ) Test Circuit
9
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
TYPICAL CHARACTERISTICS
OUTPUT-VOLTAGE
vs
OUTPUT CURRENT, DRIVER
VOL AND VOH EXTREMES
vs
FREE-AIR TEMPERATURE, DRIVER
0
0
VOH AND VOL EXTREMES FOR DRIVERS
TA = 25C
Voltage Characteristics − V
−0.5
VOH
−1
−1.5
−2
−2.5
VOL
−3
−3.5
−50
−40
−30
−20
−10
VCC = 4.5 V to 5.5 V,
Load = 100 −0.5
−2
0
50
100
TA − Free-Air Temperature − C
Figure 11.
DIFFERENTIAL OUTPUT VOLTAGE
vs
FREE-AIR TEMPERATURE, DRIVER
MINIMUM VOH AND VOL
vs
FREE-AIR TEMPERATURE, RECEIVER
150
4
VDD Max
VCC = 4.5 V to 5.5 V
Load = 100 VCC = 4.5 V
3.5
1.4
VO − Output Voltage − V
oltage − V
VOD − Differential Output V
VOL Min
Figure 10.
1.6
VDD Nom
1.2
VDD Min
1
VOH Min
3
2.5
2
1.5
1
0.5
0
50
100
TA − Free−Air T emperature − °C
Figure 12.
10
VOL Max
−2.5
IO − Output Current − mA
0.8
−50
VOH Min
−1.5
−3
−50
0
VOH Max
−1
150
0
−50
VOL Min
0
50
100
TA − Free-Air Temperature − °C
Figure 13.
150
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
TYPICAL CHARACTERISTICS (continued)
PROPAGATION DELAY TIME tP1 or tP2
vs
FREE-AIR TEMPERATURE, DRIVER
LOW-TO-HIGH PROPAGATION DELAY
vs
FREE-AIR TEMPERATURE, RECEIVER
6
tPLH − Low-to-High Propagation Delay − ns
VCC = 4.5 V to 5.5 V
Load = 100 1.4
1.2
Max Delay
1
Min Delay
0.8
0
−50
0
50
100
VCC = 5 V
5
Max
4
Nom
3
Min
2
−50
150
0
50
100
TA − Free−Air Temperature − C
T − Temperature For Driver− C
Figure 14.
150
Figure 15.
HIGH-TO-LOW PROPAGATION DELAY
vs
FREE-AIR TEMPERATURE, RECEIVER
6
t PHL− High-to-Low Propagation Delay − ns
t pd − Propagation Delay Time − ns
1.6
VCC = 5 V
5
Max
4
Nom
3
Min
2
−50
0
50
100
150
TA − Free−Air Temperature − C
Figure 16.
11
TB5T1
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SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
APPLICATION INFORMATION
140
Power Dissipation
There are two common approaches to estimating the
internal die junction temperature, TJ. In both of these
methods, the device internal power dissipation PD
needs to be calculated This is done by totaling the
supply power(s) to arrive at the system power
dissispation:
V
120
Thermal Impedance − C/W
The power dissipation rating, often listed as the
package dissipation rating, is a function of the ambient temperature, TA, and the airflow around the
device. This rating correlates with the device's maximum junction temperature, sometimes listed in the
absolute maximum ratings tables. The maximum
junction temperature accounts for the processes and
materials used to fabricate and package the device,
in addition to the desired life expectancy.
D, Low−K
DW, Low−K
100
80
DW, High−K
D, High−K
60
40
0
100
Sn I Sn
and then subtracting the total power dissipation of the
external load(s):
(V
Ln I Ln)
The first TJ calculation uses the power dissipation
and ambient temperature, along with one parameter:
θJA, the junction-to-ambient thermal resistance, in
degrees Celsius per watt.
The product of PD and θJA is the junction temperature
rise above the ambient temperature. Therefore:
T J T A PD JA
Note that θJA is highly dependent on the PCB on
which the device is mounted and on the airflow over
the device and PCB. JEDEC/EIA has defined
standardized test conditions for measuring θJA. Two
commonly used conditions are the low-K and the
high-K boards, covered by EIA/JESD51-3 and
EIA/JESD51-7 respectively. Figure 17 shows the
low-K and high-K values of θJA versus air flow for this
device and its package options.
200
300
400
Figure 17. Thermal Impedance vs Air Flow
The standardized θJA values may not accurately
represent the conditions under which the device is
used. This can be due to adjacent devices acting as
heat sources or heat sinks, to nonuniform airflow, or
to the system PCB having significantly different thermal characteristics than the standardized test PCBs.
The second method of system thermal analysis is
more accurate. This calculation uses the power
dissipation and ambient temperature, along with two
device and two system-level parameters:
• θJC, the junction-to-case thermal resistance, in
degrees Celsius per watt
• θJB, the junction-to-board thermal resistance, in
degrees Celsius per watt
• θCA, the case-to-ambient thermal resistance, in
degrees Celsius per watt
• θBA, the board-to-ambient thermal resistance, in
degrees Celsius per watt.
In this analysis, there are two parallel paths, one
through the case (package) to the ambient, and
another through the device to the PCB to the ambient. The system-level junction-to-ambient thermal impedance, θJA(S), is the equivalent parallel impedance
of the two parallel paths:
T J T A PD JA(S)
where
JA(S) 12
500
Air Flow − LFM
JC CA JB BA
JC CA JB BA
TB5T1
www.ti.com
SLLS589B – NOVEMBER 2003 – REVISED MAY 2004
Load Circuits
The test load circuits shown in Figure 6 and Figure 7 are based on a recommended pi type of load circuit shown
in Figure 18. The 100-Ω differential load resistor RT at the receiver provide proper termination for the
interconnecting transmission line, assuming it has a 100-Ω characteristic impedance. The two resistors RS to
ground at the driver end of the transmission line link provide dc current paths for the emitter follower output
transistors. The two resistors to ground normally should not be placed at the receiver end, as they shunt the
termination resistor, potentially creating an impedance mismatch with undesirable reflections.
Transmission Line
RT = 100 Ω
INPUT
RS
RS
OUTPUT
Recommended Resistor Values:
For 5 V Nom Supplies, RS = 200 Ω.
For 3.3 V Nom Supplies, RS = 75 Ω.
Figure 18. A Recommended pi Load Circuit
Another common load circuit, a Y load, is shown in Figure 19. The receiver-end line termination of RT is provided
by the series combination of the two RT/2 resistors, while the dc current path to ground is provided by the single
resistor RS. Recommended values, as a function of the nominal supply voltage range, are indicated in the figure.
Transmission Line
INPUT
OUTPUT
Recommended Resistor Values:
For 5 V Nom Supplies, RT = 200 Ω, RS = 90 Ω
For 3.3 V Nom Supplies, RT = 100 Ω, RS = 30 Ω
RT/2
RT/2
RS
Figure 19. A Recommended Y Load Circuit
An additional load circuit, similar to one commonly used with ECL and PECL, is shown in Figure 20.
Transmission Line
INPUT
OUTPUT
Recommended Resistor Values:
For 5 V and 3.3 V Nom Supplies, RT = 100 Ω,
VT = VCC − 2.55 V
RT/2
RT/2
+
_
VT
Figure 20. A Recommended PECL-Style Load Circuit
An important feature of all of these recommended load circuits is that they ensure that both of the emitter follower
output transistors remain active (conducting current) at all times. When deviating from these recommended
values, it is important to make sure that the low-side output transistor does not turn off. Failure to do so
increases the tskew2 and VOC(PP) values, increasing the potential for electromagnetic radiation.
13
PACKAGE OPTION ADDENDUM
www.ti.com
30-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TB5T1D
ACTIVE
SOIC
D
16
40
Pb-Free
(RoHS)
CU NIPDAU
Level-2-250C-1YEAR/
Level-1-220C-UNLIM
TB5T1DR
ACTIVE
SOIC
D
16
2500
Pb-Free
(RoHS)
CU NIPDAU
Level-2-250C-1YEAR/
Level-1-220C-UNLIM
TB5T1DW
ACTIVE
SOIC
DW
16
40
Pb-Free
(RoHS)
CU NIPDAU
Level-2-250C-1YEAR/
Level-1-220C-UNLIM
TB5T1DWR
ACTIVE
SOIC
DW
16
2000
Pb-Free
(RoHS)
CU NIPDAU
Level-2-250C-1YEAR/
Level-1-220C-UNLIM
Lead/Ball Finish
MSL Peak Temp (3)
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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