Datasheet
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SWITCHING CHARACTERISTICS, 5-V NOMINAL SUPPLY
TB5D1M , TB5D2H
SLLS579C – SEPTEMBER 2003 – REVISED JANUARY 2008
THIRD STATE — A TB5D1M (or TB5D2H) driver produces pseudo-ECL levels, and has a third-state mode, which
is different than a conventional TTL device. When a TB5D1M (or TB5D2H) driver is placed in the third state, the
base of the output transistors is pulled low, bringing the outputs below the active-low level of standard PECL
devices. [For example: The TB5D1M low output level is typically 2.7 V, while the third state output level is less
than 0.1 V.] In a bidirectional, multipoint, bus application, the driver of one device, which is in its third state, may
be back driven by another driver on the bus whose voltage in the low state is lower than the third-stated device.
This could come about due to differences in the driver's independent 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 voltage
between the independent driver power supplies is small, this consideration can be ignored. Again using the
TB5D1M 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.
over recommended operating conditions unless otherwise noted
parameter test conditions min typ
(1)
max unit
t
P1
Propagation delay time, input high to output
(2)
1.2 2
C
L
= 5 pF, See Figure 1 and
ns
Figure 3
t
P2
Propagation delay time, input low to output
(2)
1.2 2
Δ t
P
Capacitive delay 0.01 0.03 ns/pF
Propagation delay time,
t
PHZ
7 12
high-level-to-high-impedance output
Propagation delay time,
t
PLZ
7 12
low-level-to-high-impedance output
C
L
= 5 pF, See Figure 2 and
ns
Figure 3
Propagation delay time,
t
PZH
5 12
high-impedance-to-high-level output
Propagation delay time,
t
PZL
4 12
high-impedance-to-low-level output
t
skew1
Output skew, |t
P1
- t
P2
| 0.15 0.3
t
shew2
Output skew, |t
PHH
- t
PHL
|, |t
PLH
- t
PLL
| 0.15 1.1
C
L
= 5 pF, See Figure 1 and
ns
Figure 3
t
skew(pp)
Part-to-part skew
(3)
0.1 1
Δ t
skew
Output skew, difference between drivers
(4)
0.3
t
TLH
Rise time (20% - 80%) 0.7 2
C
L
= 5 pF, See Figure 1 and
ns
Figure 3
t
THL
Fall time (80% - 20%) 0.7 2
(1) All typical values are at 25C and with a 5-V supply.
(2) Parameters t
P1
and t
P2
are measured from the 1.5 V point of the input to the crossover point of the outputs (see Figure 1 ).
(3) t
skew(pp)
is the magnitude of the difference in differential propagation delay times, t
P1
or t
P2
, 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.
(4) Δ t
skew
is the magnitude of the difference in differential skew t
skew1
between any specified outputs of a single device.
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