Data Sheet
March 2001
Dual Differential Transceiver BTF1A
With Idle Bus Indicator
Features
Driver Features
s
s
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Electrostatic discharge (ESD) performance better
than the 41 Series
Lower power requirement than the 41 Series
s
Produces a logic zero in third state
400 mV difference voltage in third state
Two line drivers per package
Logic to convert TTL input logic levels to differen-
tial, pseudo-emmiter coupled logic (ECL) output
logic levels
No line loading when V
CC
= 0 V
High output driver for 50
Ω
loads
200 mA short-circuit current (typical)
2.0 ns maximum propagation delay
<0.2 ns output skew (typical)
Description
The BTF1A device is a dual differential transceiver
circuit that transmits and receives digital data over
balanced transmission lines and is compatible with
Lucent Technologies Microelectronics Group differ-
ential drivers and receivers. It is designed to provide
a strong logic zero when in the third state. The mini-
mum difference voltage in the third state is 400 mV. It
is designed specifically for bus applications where a
well-defined logic state is needed when the bus is
idle. The driver puts out a logic
zero
when in the third
state mode, which is easily overriden by an active
buffer on the bus. When all the buffers on the bus are
inactive (third state), the signal on the bus is a
zero
indicating that the bus is idle.
The dual drivers translate input TTL logic levels to dif-
ferential pseudo-ECL output levels. The dual receiver
converts differential input logic levels to TTL output
levels. Each driver/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 BTF1A transceiver requires the customer
to supply termination resistors on the circuit board.
The powerdown loading characteristics of the
receiver input circuit are approximately 8 kΩ relative
to the power supplies; hence, it will not load the
transmission line when the circuit is powered down.
For those circuits with termination resistors, the line
will remain impedance matched when the circuit is
powered down. The driver does not load the line
when it is powered down.
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Receiver Features
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Two line receivers per package
High input impedance
≅
8 kΩ
Logic that converts differential input logic levels to
TTL output logic levels
4.0 ns maximum propagation delay
<0.20 V input sensitivity (typical)
−1.2
V to
+7.2
V common-mode range
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s
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Common Device Features
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Common enable for each driver/receiver pair
Operating temperature range: –40
°C
to +125
°C
(wider than the 41 Series)
Single 5.0 V
±
5% supply
400 Mbits/s maximum data rate
Meets enhanced small device interface (ESDI)
standards
s
s
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Dual Differential Transceiver BTF1A
With Idle Bus Indicator
Data Sheet
March 2001
Pin Information
RO1
DI1
V
CC
ED
ER
GND
DI2
RO2
1
R1
2
3
D1
4
5
D2
6
7
R2
8
BTF1A
16 RI1
15 RI1
14 DO1
13 DO1
12 DO2
11 DO2
10 RI2
9
RI2
12-2747.a(F)
Figure 1. Differential Transceiver Logic Diagram
Table 1. Enable Truth Table
ED
0
1
0
1
ER
0
0
1
1
D1
Active
Disabled
Active
Disabled
D2
Active
Disabled
Active
Disabled
R1
Active
Active
Disabled
Disabled
R2
Active
Active
Disabled
Disabled
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operational sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter
Power Supply Voltage
Ambient Operating Temperature
Storage Temperature
Symbol
V
CC
T
A
T
stg
Min
—
−40
−55
Max
6.5
125
150
Unit
V
°C
°C
2
Agere Systems Inc.
Data Sheet
March 2001
Dual Differential Transceiver BTF1A
With Idle Bus Indicator
Electrical Characteristics
For variations in electrical characteristics over the temperature range, see Figure 10 through Figure 12.
Table 3. Power Supply Current Characteristics
T
A
=
−40
°C to +125 °C, V
CC
= 5 V
±
0.25 V.
Parameter
Power Supply Current (V
CC
= 5.5 V)
All Outputs Disabled
All Outputs Enabled
Symbol
I
CC
I
CC
Min
—
—
Typ
40
20
Max
65
35
Unit
mA
mA
Third State
The BTF1A driver produces pseudo-ECL levels, and has a third-state mode, which is different than a conventional
TTL device. When a driver is placed in the third state, the base of the output transistors are pulled low, bringing the
outputs below the active-low level. The BTF1A is unique because it provides a logic zero at its output when in the
third state. If all the buffers on the bus are in the third state, the BTF1A is designed to deliver a logic zero to the bus
to act as an indicator that the bus is idle. The guaranteed zero level, Vdo – Vdo, is 0.4 V.
Agere Systems Inc.
3
Dual Differential Transceiver BTF1A
With Idle Bus Indicator
Data Sheet
March 2001
Electrical Characteristics
(continued)
Table 4. Driver Voltage and Current Characteristics
For variations in output voltage over the temperature range, see Figure 10 and Figure 11. T
A
=
−40
°C to +125 °C.
Parameter
Output Voltages:
Low
1
High
1
:
Differential Voltage (V
OH
– V
OL
)
Output Voltage Third State:
Difference Voltage Vdo - Vdo
Third State, I
OH
= –1.0 mA, V
CC
= 4.75 V
Output Voltages (T
A
= 0 °C to 85 °C):
Low
1
High
1
:
Differential Voltage (V
OH
– V
OL
)
Input Voltages:
Low, V
CC
= 5.25 V:
Data Input
Enable Input
High, V
CC
= 4.75 V
Clamp, V
CC
= 4.75 V, I
I
= –5.0 mA
Short-circuit Output Current, V
CC
= 5.25 V
Input Currents, V
CC
= 5.25 V:
Low, V
I
= 0.4 V
High, V
I
= 2.7 V
Reverse, V
I
= 5.25 V
Symbol
V
OL
V
OH
V
DIFF
V
DIFZ
V
OZ
V
OL
V
OH
V
DIFF
V
IL
2
V
IL
3
V
IL
3
V
IH
2
V
IK
I
OS
I
IL
I
IH
I
IH
Min
V
OH
– 1.4
V
CC
−
1.8
0.65
0.4
—
V
OH
– 1.4
V
CC
−
1.5
0.8
—
—
—
2.0
—
–100
—
—
—
Typ
V
OH
−
1.1
V
CC
−
1
1.1
0.6
—
V
OH
−
1.1
V
CC
−
1
1.1
—
—
—
—
—
—
—
—
—
Max
V
OH
−
0.65
V
CC
−
0.8
1.4
—
V
OL
−
0.2
V
OH
−
0.8
V
CC
−
0.8
1.4
0.8
0.8
0.7
—
−1.0
—
−400
20
100
Unit
V
V
V
V
V
V
V
V
V
V
V
V
V
mA
µA
µA
µA
1. Values are with terminations as per Figure 7.
2. The input levels and difference voltage provide zero noise immunity and should be tested only in a static, noise-free environment.
3. Test must be performed one lead at a time to prevent damage to the device.
4
Agere Systems Inc.
Data Sheet
March 2001
Dual Differential Transceiver BTF1A
With Idle Bus Indicator
Electrical Characteristics
(continued)
Table 5. Receiver Voltage and Current Characteristics
For variation in minimum V
OH
and maximum V
OL
over the temperature range, see Figure 10. T
A
= –40 °C to +125 °C.
Parameter
Output Voltages V
CC
= 4.75 V:
Low, I
OL
= 8.0 mA
1
High, I
OH
=
−400
µA
Enable Input Voltages:
Low, V
CC
= 5.25 V
High, V
CC
= 4.75 V
Clamp, V
CC
= 4.75 V, I
I
= –5.0 mA
Minimum Differential Input Voltages, V
IH –
V
IL
:
2
−0.80
V < V
IH
< 7.2 V,
−1.2
V < V
IL
< 6.8 V
Input Offset Voltage
Output Currents, V
CC
= 5.25 V:
Off-state (high Z), V
O
= 0.4 V
Off-state (high Z), V
O
= 2.4 V
Short Circuit
Enable Input Currents, V
CC
= 5.25 V:
Low, V
IN
= 0.4 V
High, V
IN
= 2.7 V
Reverse, V
IN
= 5.5 V
Differential Input Currents:
Low, V
IN
= –1.2 V
High, V
IN
= 7.2 V
Symbol
V
OL
V
OH
V
IL
1
V
IH
1
V
IK
V
TH
1
V
OFF
I
OZL
I
OZH
I
OS
3
I
IL
I
IH
I
IH
I
IL
I
IH
Min
—
2.4
—
2.0
—
—
—
—
–25
—
—
—
—
—
Typ
—
—
—
—
—
0.1
0.03
—
—
—
—
—
—
—
—
Max
0.5
—
0.7
—
−1.0
0.20
0.05
–20
20
–100
–400
20
100
−1.0
1.0
Unit
V
V
V
V
V
V
V
µA
µA
mA
µA
µA
µA
mA
mA
1. The input levels and difference voltage provide zero noise immunity and should be tested only in a static, noise-free environment.
2. Outputs of unused receivers assume a logic 1 level when the inputs are left open. (It is recommended that all unused positive inputs
be tied to the positive power supply. No external series resistor is required.)
3. Test must be performed one lead at a time to prevent damage to the device.
Agere Systems Inc.
5
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