GTLP8T306 8-Bit LVTTL/GTLP Bus Transceiver
September 1997
Revised December 2000
GTLP8T306
8-Bit LVTTL/GTLP Bus Transceiver
General Description
The GTLP8T306 is an 8-bit bus transceiver that provides
LVTTL to GTLP signal level translation. The device pro-
vides a high speed interface between cards operating at
LVTTL logic levels and a backplane operating at GTLP
logic levels. High speed backplane operation is a direct
result of GTLP’s reduced output swing (
<
1V), reduced input
threshold levels and output edge rate control. The edge
rate control minimizes bus settling time. GTLP is a Fairchild
Semiconductor derivative of the Gunning Transceiver logic
(GTL) JEDEC standard JESD8-3.
Fairchild’s GTLP has internal output edge-rate control and
is process, voltage, and temperature (PVT) compensated.
Its function is similar to BTL and GTL but with different out-
put levels and receiver thresholds. The GTLP output LOW
level is typically less than 0.5V, the output HIGH level is
1.5V and the receiver threshold is 1.0V.
Features
s
Bidirectional interface between GTLP and LVTTL logic
levels
s
Designed with edge rate control circuitry to reduce out-
put noise on the GTLP port
s
V
REF
pin provides external supply reference voltage for
receiver threshold adjustibility
s
Special PVT Compensation circuitry to provide consis-
tent performance over variations of process, supply volt-
age and temperature
s
TTL compatible driver and control inputs
s
Designed using Fairchild advanced CMOS technology
s
Bushold data inputs on A port to eliminate the need for
external pull-up resistors for unused inputs
s
Power up/down and power off high impedance for live
insertion
s
5V over voltage tolerance on LVTTL ports
s
Open drain on GTLP to support wired-or connection
s
Flow through pinout optimizes PCB layout
s
A Port source/sink
−
24mA/
+
24mA
s
B Port sink
+
50mA
Ordering Code:
Order Number
GTLP8T306MTC
Package Number
MTC24
Package Description
24-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
© 2000 Fairchild Semiconductor Corporation
DS500051
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GTLP8T306
Pin Descriptions
Pin Names
OE
T/R
A0–A7
B0–B7
V
REF
Description
Output Enable (Active LOW)
Transmit/Receive Input
Side A Inputs or 3-STATE Outputs
Side B Inputs or 3-STATE Outputs
GTLP Reference Voltage
Truth Table
Inputs
Output
OE
H
L
L
T/R
X
L
H
HIGH Z on Bus A and Bus B
Bus B Data to Bus A
Bus A Data to Bus B
Functional Description
The GTLP8T306 is an 8-bit transceiver providing the standard 245 functionality that supports both GTL and GTLP signal
levels.
Data polarity is non-inverting and the data flow direction is controlled by the T/R pin. The outputs are enabled to allow data
through the device when OE is LOW otherwise both the A and B ports are placed in a HIGH impedance state.
Logic Diagram
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2
GTLP8T306
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
CC
)
DC Input Voltage (V
I
)
DC Output Voltage (V
O
)
Outputs 3-STATE
Outputs Active (Note 2)
DC Output Sink Current into A-Port, I
OL
DC Output Source Current from
A Port I
OH
DC Output Sink Current into B-Port
in the LOW State, I
OL
DC Input Diode Current (I
IK
)
V
I
<
0V
DC Output Diode Current (I
OK
)
V
O
<
0V
V
O
>
V
CC
ESD Rating
Storage Temperature (T
STG
)
100 mA
−
0.5V to 7.0V
−
0.5V to
+
7.0V
−
0.5V to
+
7.0V
−
0.5V to 7.0V
48 mA
Recommended Operating
Conditions
(Note 3)
Supply Voltage V
CC
Bus Termination Voltage (V
TT
)
GTLP
GTL
Input Voltage (V
I
) on A-Port
and control pins
0V to 5.5V
HIGH Level Output Current (I
OH
)
A Port
LOW Level Output Current (I
OL
)
A Port
1.35V to 1.65V
1.14V to 1.26V
3.15V to 3.45V
−
48 mA
−
24 mA
+
24 mA
+
50 mA
−
40
°
C to
+
85
°
C
−
50 mA
−
50 mA
+
50 mA
>
2000V
−
65
°
C to
+
150
°
C
B Port
Operating Temperature (T
A
)
Note 1:
The Absolute Maximum Ratings are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum rating.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Note 2:
I
O
Absolute Maximum Rating must be observed.
Note 3:
Unused inputs must be held HIGH or LOW.
DC Electrical Characteristics
Over Recommended Operating Free-Air Temperature Range, V
REF
=
1.0V (unless otherwise noted).
Symbol
V
IH
V
IL
V
REF
V
IK
V
OH
A Port
B Port
Others
B Port
Others
GTLP
GTL
V
CC
=
3.15V
V
CC
=
Min to Max (Note 5)
V
CC
=
3.15V
V
OL
A Port
B Port
I
I
A Port
Control Pins
B Port
I
OFF
I
I
(Hold)
I
OZH
I
OZL
A Port
A Port
A Port
B Port
A Port
B Port
V
CC
=
3.45V
V
CC
=
3.45V
V
CC
=
Min to Max (Note 5)
V
CC
=
3.15V
V
CC
=
3.15V
V
CC
=
3.45V
V
CC
=
3.45V
V
CC
=
3.45V
V
CC
=
0
V
CC
=
3.15V
V
CC
=
3.45V
I
I
= −18
mA
I
OH
= −100 µA
I
OH
= −12
mA
I
OH
= −24
mA
I
OL
=
100
µA
I
OL
=
24 mA
I
OL
=
40 mA
I
OL
=
50 mA
V
I
=
5.5V
V
I
=
0V
V
I
=
5.5V
V
I
=
0V
V
I
=
V
TT
V
I
=
0
V
I
or V
O
=
0 to 4.5V
V
I
=
0.8V
V
I
=
2.0V
V
O
=
3.45V
V
O
=
1.5V
V
O
=
0
V
O
=
0.55
75
−20
20
5
−20
−5
V
CC
−0.2
2.4
2.0
0.2
0.5
0.4
0.55
20
−20
5
−5
5
−5
100
V
V
µA
µA
µA
µA
µA
µA
µA
V
1.0
0.8
−1.2
Test Conditions
Min
V
REF
+0.05
2.0
0.0
V
REF
−0.05
0.8
Typ
(Note 4)
V
TT
V
V
V
V
V
V
V
Max
Units
3
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GTLP8T306
DC Electrical Characteristics
Symbol
I
CC
A or B Ports
V
CC
=
3.45V
I
O
=
0
V
I
=
V
CC
or GND
I
CC
(Note 6)
C
IN
A Port and
Control Pins
Control Pins
A Port
B Port
Note 4:
All typical values are V
CC
=
3.3V and T
A
=
25°C.
(Continued)
Min
Typ
(Note 4)
7
8
8
0
5
7
9
pF
18
20
20
1
mA
mA
Max
Units
Test Conditions
Outputs HIGH
Outputs LOW
Outputs Disabled
One Input at V
CC
–0.6V
V
I
=
V
CC
or 0
V
I
=
V
CC
or 0
V
I
=
V
CC
or 0
V
CC
=
3.45V
A or Control Inputs at V
CC
or GND
Note 5:
For conditions shown as Min, use the appropriate value specified under recommended operating conditions.
Note 6:
This is the increase in supply current for each input that is at the specified LVTTL voltage level rather than V
CC
or GND.
AC Electrical Characteristics
Over recommended range of supply voltage and operating free air-temperature, V
REF
=
1.0V (unless otherwise noted).
C
L
=
30 pF for B Port and C
L
=
50 pF for A Port.
Min
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
RISE
t
FALL
t
RISE
t
FALL
t
PZH
, t
PZL
t
PHZ
, t
PLZ
t
PLH
t
PHL
Note 7:
All typical values are at V
CC
=
3.3V and T
A
=
25°C.
Typ
(Note 7)
Max
Units
From (Input)
An
To (Output)
Bn
1.0
1.0
4.0
5.1
5.8
4.9
2.6
2.6
2.5
2.5
An
1.0
1.0
4.5
4.9
5.4
6.0
9.5
ns
9.5
9.5
ns
1.0
9.5
7.5
ns
7.5
8.3
ns
1.0
8.3
ns
ns
ns
ns
Bn
An
1.0
Transition Time, B Outputs (20% to 80%)
Transition Time, B Outputs (20% to 80%)
Transition Time, A Outputs (10% to 90%)
Transition Time, A Outputs (10% to 90%)
OE
OE
Bn
1.0
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4
GTLP8T306
Test Circuit and Timing Waveforms
Test Circuit for A Outputs
Test Circuit for B Outputs
Voltage Waveforms Pulse Duration
(V
M
=
V
CC
/2 for A Port and 1.0 for B-Port)
Voltage Waveforms Enable and
Disable Times A Port
Voltage Waveforms Propagation Delay and Setup and Hold Times
(V
M
=
V
CC
/2 for A Port and 1.0 for B Port)
Note A:
C
L
includes probes and Jig capacitance.
Note B:
For B Port, C
L
=
30 pF is used for worst case.
5
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