Application Information (Continued) 
Receive Mode
Input(s) Input/Output
DE RE
*
[RI+] − [RI−] RO
LL
>
+100 mV H
LL
<
−100 mV L
L L 100 mV
>&>
−100 mV X
LH X Z
Transmit Mode
Input(s) Input/Output
DE RE
*
DI DO+ DO−
HH L L H 
HHHHL 
HH2
>
&
>
0.8 X X
LH X Z Z
H
=
Logic high level 
L=Logic low level 
X=Indeterminant state 
Z=High impedance state
TABLE 1. Device Pin Descriptions
Pin
#
Name Mode Description
(In mode only)
3 DE Transmit Driver Enable: When asserted low driver is disabled. And when
asserted high driver is enabled.
1, 7 DI TTL/CMOS driver input pins 
10, 13 DO+ Non-inverting driver output pin 
11, 12 DO− Inverting driver output pin
4RE
*
Receive Receiver Enable: When asserted low receiver is enabled. And when
asserted high receiver is disabled.
1, 7 RO Receiver output pin 
10, 13 RI+ Positive receiver input pin 
11, 12 RI− Negative receiver input pin
5 GND Transmit and Ground pin 
2V
CC
Receive Positive power supply pin, +5V±10
%
6, 8, 9, 14 NC No Connect
IEEE 1394
The DS36C200 drives and receives IEEE 1394 physical 
layer signal levels. The current mode driver is capable of 
driving a 55Ω load with V
OD
between 172 mV and 285 mV. 
The DS36C200 is not designed to work with a link layer controller IC requiring full 1394 physical layer compliancy to the 
standard. No clock generator, no arbitration, and no encode/ 
decode logic is provided with this device. For a 1394 link 
where speed sensing, bus arbitration, and other functions 
are not required, a controller and the DS36C200 will provide 
a cost effective, high speed dedicated link. This is shown in
Figure 10
. In applications that require fully compliant 1394 
protocol, a link layer controller and physical layer controller 
will be required as shown in
Figure 10
. The physical layer 
controller supports up to three DC36C200 devices (not 
shown).
The DS36C200 drivers are current mode drivers and intended to work with a two 110Ω termination resistors in parallel with each other. The termination resistors should match 
the characteristic impedance of the transmission media. The 
drivers are current mode devices therefore the resistors are 
required. Both resistors are required for half duplex operation and should be placed as close to the DO/RI+ and DO/ 
RI− pins as possible at opposite ends of the bus. However,if 
your application only requires simplex operation, only one 
termination resistor is required. In addition, note the voltage 
levels will vary from those in the datasheet due to different 
loading. Also, AC or unterminated configurations are not 
used with this device. Multiple node configurations are pos-
sible as long as transmission line effects are taken into account. Discontinuities are caused by mid-bus stubs, connectors, and devices that affect signal integrity.
The differential line driver is a balanced current source design. A current mode driver, generally speaking has a high 
output impedance and supplies a constant current for a 
range of loads (a voltage mode driver on the other hand supplies a constant voltage for a range of loads). Current is 
switched through the load in one direction to produce a logic 
state and in the other direction to produce the other logic 
state. The typical output current is mere 3.8 mA, a minimum 
of 3.1 mA, and a maximum of 5.2 mA. The current mode re- 
quires that a resistive termination be employed to terminate 
the signal and to complete the loop as shown in
Figure 11
. 
The 3.8 mA loop current will develop a differential voltage of 
210 mV across the 55Ω termination resistor which the receiver detects with a 110mV minimum differential noise margin neglecting resistive line losses (driven signal minus receiver threshold (210 mV – 100 mV=110 mV)). The signal 
is centered around +1.2V (Driver Offset, V
OS
) with respect to
ground as shown in
Figure 7
.
The current mode driver provides substantial benefits over 
voltage mode drivers, such as an RS-422 driver. Its quiescent current remains relatively flat versus switching frequency.Whereas the RS-422 voltage mode driver increases 
exponentially in most case between 20 MHz–50 MHz. This 
is due to the overlap current that flows between the rails of 
the device when the internal gates switch. Whereas the current mode driver switches a fixed current between its output 
without any substantial overlap current. This is similar to
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