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AN1259.0
ISL41334EVAL1Z User’s Manual
Description
The ISL41334 evaluation board is RoHS compliant, and
provides a quick and easy method for evaluating this two
port Dual Protocol IC. The eval board also accommodates
the ISL41387; see the “ISL41387EVAL1Z User’s Manual” for
details.
This board was designed to allow the user to evaluate all the
features available on the ISL81334 and ISL41334 products.
The ISL41334 is the full featured version (see “Features”
below), where the QFN package’s increased pin count gives
the user access to functionality not available on the pin
limited ISL81334. The same die is used in both products, so
other than minor package effects, evaluating the QFN
packaged ISL41334 is a reasonable substitute for evaluating
the ISL81334.
By changing jumper positions the user can quickly set the
board to evaluate any of the ISL41334’s many modes and
features, and the input states can also be set via jumpers.
Refer to the data sheet for complete details regarding the
functions and features of this device. These dual protocol
ICs feature many modes, so studying the device’s truth-table
along with its operating circuits and detailed description is
the best way to gain an understanding of how the part works.
Features
• QFN Version Demonstrates All Enhanced Features:
Logic Supply Pin (V
L
)
Three RS-485 Speed Options - 115kbps/460kbps/20Mbps
Active Low RS-485 Rx Enable for Simple Direction Control
• Quick Configuration Using Jumpers
• State of All Inputs Can be Set by Jumper Positions
• No Bus Termination Resistors on Port 1 Allows Easy
RS-232 Evaluation; Bus Termination Resistors on Port 2
for RS-485 Evaluation
• Simple Operation Requires Only One, 5V, Power Supply
Important Notes
To facilitate locating jumpers on this board, Figure 3 is a
jumper locator and, in this App Note, the (#) following a
jumper mention corresponds to the red jumper number on
the locator. See the “Jumper Definitions” section for a
description of the function of each jumper.
The base board is used to evaluate both the ISL41334 (2 port)
and ISL41387 (1 port) products, so the jumper and connector
names reflect the functionality of both products. Due to space
limitations some jumper labels are abbreviated, but the
corresponding BNC connector has the full label.
In most cases, a name that applies to both products contains
no parenthesis (e.g., “B1”), a name that applies to only the
ISL41334 is followed by “(NC)” (e.g., “B2 (NC)”), and a name
that applies to only the ISL41387 is preceded by “NC” and/or
has the name in parenthesis (e.g., “NC (DEN)” or “(DEN)”).
Note that on “Rev. A” of these boards the following minor
errors have been noted, and are corrected on subsequent
revisions:
• Jumper label “A2/Y2_LB” (9) should be “B2/Z2_LB”.
• Jumper label “B2/Z2_LB” (10) should be “A2/Y2_LB”.
• Jumper labels “J-SELX” (7 and 8) should be “J-SELX
(NC)” because they are not used for the ISL41387.
• Jumper label “J-RXEN2
” (18) should be “J-RXEN2 (NC)”
because it is not used for the ISL41387.
• Jumper label “J-RXEN” (not numbered) should be
“J-(RXEN)” because it is only used for the ISL41387.
• Jumper label “J-DE2” (19) should be “J-DE2 (NC)”
because it is not used for the ISL41387.
• Jumper label “J-DY2” (20) should be “J-DY2 (NC)”
because it is not used for the ISL41387.
• Jumper label “J-ON/OFF
” (21) should be “J-ON/OFF (NC)”
because it is not used for the ISL41387.
• Jumper label “J-(SLEW)” (23) should be “J-DY1 (SLEW)”.
• Jumper label “J-DE1” (24) should be “J-DZ1/DE1 (DY)”.
It is important to note that the ISLX1334 don’t follow the
RS-485 convention whereby the inverting I/O is labeled
“B/Z”, and the noninverting I/O is “A/Y”. Thus, the ISL41334
A/Y (B/Z) pins connect to the B/Z (A/Y) pins of generic
RS-485/422 ICs.
Input signals that connect to a BNC connector, because they
are likely to be driven by a generator, include a 50Ω
termination resistor to GND when the jumper is in the “LOW”
position.
Port 1 includes no Rx input nor Tx output termination
resistors, as this port is intended for RS-232 evaluation.
Port 2, intended for RS-485/422 evaluation, includes 120Ω
differential termination resistors across the Rx inputs, and
across the Tx outputs.
Default Configuration
As delivered (see “Functional Diagram”), the board is
configured for port 1 in RS-232 mode with Tx and Rx
enabled (Tx is always enabled in RS-232 mode), Rx inputs
floating, and Tx inputs low. Port 2 is in RS-485 mode with Tx
and Rx enabled, Tx set for high speed (20Mbps) operation,
driver input (DY) low, Rx inputs floating but shorted together
Application Note May 31, 2006
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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