DS34C87T
CMOS Quad TRISTATE Differential Line Driver
General Description
The DS34C87T is a quad differential line driver designed for
digital data transmission over balanced lines. The
DS34C87T meets all the requirements of EIA standard
RS-422 while retaining the low power characteristics of
CMOS. This enables the construction of serial and terminal
interfaces while maintaining minimal power consumption.
The DS34C87T accepts TTL or CMOS input levels and
translates these toRS-422output levels. This part uses special output circuitry that enables the individual drivers to
power down without loading down the bus. This device has
separate enable circuitry for each pair of the four drivers.
The DS34C87T is pin compatible to the DS3487T.
All inputs are protected against damage due to electrostatic
discharge by diodes to V
CC
and ground.
Features
n TTL input compatible
n Typical propagation delays: 6 ns
n Typical output skew: 0.5 ns
n Outputs won’t load line when V
CC
=
0V
n Meets the requirements of EIA standard RS-422
n Operation from single 5V supply
n TRI-STATE outputs for connection to system buses
n Low quiescent current
n Available in surface mount
Connection and Logic Diagrams
Truth Table
Input Control Non-Inverting Inverting
Input Output Output
HH H L
LH L H
XL Z Z
L = Low logic state
H = High logic state
X = Irrelevant
Z = TRI-STATE (high performance)
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
Dual-In-Line Package
DS008576-1
Top View
Order Number DS34C87TM or DS34C87TN
See NS Package Number M16A or N16E
DS008576-2
May 1998
DS34C87T CMOS Quad TRI-STATE
™
Differential Line Driver
© 1998 National Semiconductor Corporation DS008576 www.national.com
Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
) −0.5 to 7.0V
DC Voltage (V
IN
) −1.5 to V
CC
+1.5V
DC Output Voltage (V
OUT
) −0.5 to 7V
Clamp Diode Current (I
IK,IOK
)
±
20 mA
DC Output Current, per pin (I
OUT
)
±
150 mA
DC V
CC
or GND Current (ICC)
±
150 mA
Storage Temperature Range (T
STG
) −65˚C to +150˚C
Maximum Power Dissipation (P
D
)@25˚C (Note 3)
Plastic “N” Package 1736 mW
SOIC Package 1226 mW
Lead Temperature (T
L
)
(Soldering 4 sec) 260˚C
This device does not meet 2000V ESD rating. (Note 12)
Operating Conditions
Min Max Units
Supply Voltage (V
CC
) 4.50 5.50 V
DC Input or Output Voltage (V
IN,VOUT
)0VCCV
Operating Temperature Range (T
A
)
DS34C87T −40 +85 ˚C
Input Rise or Fall Times (t
r,tf
) 500 ns
DC Electrical Characteristics (Note 4)
V
CC
=
5V
±
10%(unless otherwise specified)
Symbol Parameter Conditions Min Typ Max Units
V
IH
High Level Input 2.0 V
Voltage
V
IL
Low Level Input 0.8 V
Voltage
V
OH
High Level Output V
IN
=
V
IH
or VIL, 2.5 3.4 V
Voltage I
OUT
=
−20 mA
V
OL
Low Level Output V
IN
=
V
IH
or VIL, 0.3 0.5 V
Voltage I
OUT
=
48 mA
V
T
Differential Output R
L
=
100 Ω 2.0 3.1 V
Voltage (Note 5)
|V
T
|–| VT| Difference In R
L
=
100 Ω 0.4 V
Differential Output (Note 5)
V
OS
Common Mode R
L
=
100 Ω 2.0 3.0 V
Output Voltage (Note 5)
|V
OS–VOS
| Difference In R
L
=
100 Ω 0.4 V
Common Mode Output (Note 5)
I
IN
Input Current V
IN
=
V
CC
, GND, VIH,orV
IL
±
1.0 µA
I
CC
Quiescent Supply I
OUT
=
0 µA,
Current V
IN
=
V
CC
or GND 200 500 µA
V
IN
=
2.4V or 0.5V (Note 6) 0.8 2.0 mA
I
OZ
TRI-STATE™Output V
OUT
=
V
CC
or GND
±
0.5
±
5.0 µA
Leakage Current Control=V
IL
I
SC
Output Short V
IN
=
V
CC
or GND −30 −150 mA
Circuit Current (Notes 5, 7)
I
OFF
Power Off Output V
CC
=
0V V
OUT
=
6V 100 µA
Leakage Current (Note 5) V
OUT
=
−0.25V −100 µA
Note 1: Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device
should be operated at these limits. The table of “Electrical Characteristics” provide conditions for actual device operation.
Note 2: Unless otherwise specified, all voltages are referenced to ground. All currents into device pins are positive; all currents out of device pins are negative.
Note 3: Ratings apply to ambient temperature at 25˚C. Above this temperature derate N Package 13.89 mW/˚C, and M Package 9.80 mW/˚C.
Note 4: Unless otherwise specified, min/max limits apply across the −40˚C to 85˚C temperature range. All typicals are given for V
CC
=
5V and T
A
=
25˚C.
Note 5: See EIA Specification RS-422 for exact test conditions.
Note 6: Measured per input. All other inputs at V
CC
or GND.
Note 7: This is the current sourced when a high output is shorted to ground. Only one output at a time should be shorted.
www.national.com 2
Switching Characteristics (Note 4)
V
CC
=
5V
±
10%,tr,tf≤6ns(
Figures 1, 2, 3, 4
)
Symbol Parameter Conditions Min Typ Max Units
t
PLH,tPHL
Propagation Delay S1 Open 6 11 ns
Input to Output
Skew (Note 8) S1 Open 0.5 3 ns
t
TLH,tTHL
Differential Output Rise S1 Open 6 10 ns
And Fall Times
t
PZH
Output Enable Time S1 Closed 12 25 ns
t
PZL
Output Enable Time S1 Closed 13 26 ns
t
PHZ
Output Disable Time (Note 9) S1 Closed 4 8 ns
t
PLZ
Output Disable Time (Note 9) S1 Closed 6 12 ns
C
PD
Power Dissipation 100 pF
Capacitance (Note 10)
C
IN
Input Capacitance 6 pF
Note 8: Skew is defined as the difference in propagation delays between complementary outputs at the 50%point.
Note 9: Output disable time is the delay from the control input being switched to the output transistors turning off. The actual disable times are less than indicated
due to the delay added by the RC time constant of the load.
Note 10: C
PD
determines the no load dynamic power consumption, P
D
=
C
PD
V2CCf+ICCVCC, and the no load dynamic current consumption, I
S
=
C
PDVCC
f+
I
CC
.
Comparison Table of Switching Characteristics into “LS-Type” Load(Note 11)
V
CC
=
5V, T
A
=
+25˚C, t
r
≤ 6 ns, tf≤ 6ns(
Figures 4, 5, 6, 7, 8, 9
)
Symbol Parameter Conditions DS34C87 DS3487 Units
Typ Max Typ Max
t
PLH,tPHL
Propagation Delay 6 10 10 15 ns
Input to Output
Skew (Note 8) 1.5 2.0 ns
t
THL,tTLH
Differential Output Rise 4 7 10 15 ns
and Fall Times
t
PHZ
Output Disable Time C
L
=
50 pF, R
L
=
200Ω, 8 11 17 25 ns
(Note 9) S1 Closed, S2 Closed
t
PLZ
Output Disable Time C
L
=
50 pF, R
L
=
200Ω, 7 10 15 25 ns
(Note 9) S1 Closed, S2 Closed
t
PZH
Output Enable Time C
L
=
50 pF, R
L
=
∞
, 11191125 ns
S1 Open, S2 Closed
t
PZL
Output Enable Time C
L
=
50 pF, R
L
=
200Ω, 14211525 ns
S1 Closed, S2 Open
Note 11: This table is provided for comparison purposes only. The values in this table for the DS34C87 reflect the performance of the device but are not tested or
guaranteed.
Note 12: ESD Rating: HBM (1.5 kΩ, 100 pF)
Inputs ≥ 1500V
Outputs ≥ 1000V
EIAJ (0Ω, 200 pF)
All Pins ≥ 350V
www.national.com3
AC Test Circuit and Switching Time Waveforms
DS008576-3
Note: C1=C2=C3=40 pF (including Probe and Jig Capacitance), R1=R2=50Ω,R3=500Ω
FIGURE 1. AC Test Circuit
DS008576-4
FIGURE 2. Propagation Delays
DS008576-5
FIGURE 3. Enable and Disable Times
DS008576-7
Input pulse; f=1 MHz, 50%,tr≤6 ns, tf≤ 6ns
FIGURE 4. Differential Rise and Fall Times
DS008576-8
FIGURE 5. Propagation Delays Test Circuit
for “LS-Type” Load
DS008576-6
FIGURE 6. Differential Rise and Fall Times
Test Circuit for “LS-Type” Load
DS008576-9
FIGURE 7. Load Enable and Disable Times
Test Circuit for “LS-Type” Load
www.national.com 4
AC Test Circuit and Switching Time Waveforms (Continued)
Typical Applications
DS008576-10
FIGURE 8. Load Propagation Delays for “LS-Type” Load
DS008576-11
FIGURE 9. Load Enable and Disable Times for “LS-Type” Load
DS008576-12
*RTis optional although highly recommended to reduce reflection.
www.national.com5
6
Physical Dimensions inches (millimeters) unless otherwise noted
16-Lead Molded Package
Small Outline (M)
Order Number DS34C87TM
NS Package Number M16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DS34C87TN
NS Package Number N16E
www.national.com7
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the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component in any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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DS34C87T CMOS Quad TRI-STATE
™
Differential Line Driver
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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