ISL3333EVAL1Z Intersil, ISL3333EVAL1Z Datasheet - Page 2

• Manufacturer Part Number: ISL3333EVAL1Z
• Description: EVAL BOARD 1 FOR ISL3333
• Manufacturer: Intersil

Specifications of ISL3333EVAL1Z

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Functional Diagram
Supply Banana Jacks
There are eight banana jacks at the top of the board for
power supply connections, but only V
required connections. The function and use of each jack
(from left to right) are:
VLOAD - This is a load voltage driving the load resistors
connected to the Rx and Tx outputs (Tx resistors - R
R
enable and disable time characterizations.
GND - Common connection for any supplies used.
RXBIAS - A voltage that can be applied to any or all Rx
inputs via jumpers ((2), (3), (11), (12)); the “RXBIAS-VCC”
(25)
supplying a voltage other than V
V+ - Used to monitor the positive charge pump voltage in
RS-232 mode.
V- - Used to monitor the negative charge pump voltage in
RS-232 mode.
VCC - The 3.3V supply connection.
VHIGH - Connects to all the “VH” positions on the jumpers to
define the high level voltage for logic and Tx inputs; the
“VL-VHIGH”
this jumper if supplying a voltage other than V
10
, R
jumper shorts this jack to V
11
- are not populated); used mostly during output
+3.3V
120Ω
0.1µF
0.1µF
120Ω
V
V
V
V
(27)
C
C
H
H
H
H
1
2
+
+
+ 0.1µF
jumper shorts this jack to V
37
38
36
35
10
20
11
13
14
9
8
2
3
4
5
6
7
SEL1
C1+
C1-
C2+
C2-
B1
SEL2
DEN2
SPA
SPB
A1
Y1
Z1
Y2
Z2
A2
B2
5kΩ
5kΩ
V
CC
34
GND
(Default Configuration)
D
2
15, 16
(26)
R
R
R
ON/OFF
D
CC
D
V
CC
RXEN1 17
RXEN2
L
31
DEN1 12
R
R
R
D
D
D
DE2 23
, so remove this jumper if
.
LB
V+
A2
A1
B1
Y1
Z1
Y2
V-
CC
(27)
29
1
19
26
30
27
28
25
24
22
18
and GND are
+ C
+
0.1µF
C
0.1µF
VHIGH (V
V
V
V
L
V
3
4
H
H
H
, so remove
L
H
.
Application Note 1470
H
5
)
, R
6
,
VL - The logic supply voltage that sets the ISL3333’s Rx
output V
points; the “VCC-VL”
remove this jumper if supplying a voltage other than V
Getting Started
Connect a 3.3V, 500mA minimum, power supply to the V
and GND banana jacks. It is recommended that an ammeter
be used between the supply and the board, in order for I
to be monitored. Ensure that the “RXBIAS-VCC” (25),
“VCC-VL”
the upper right hand corner of the board.
For simplicity, the following discussions assume that Port 1
is used for RS-232 evaluations, and Port 2 for RS-485
evaluations. Of course, the user is free to configure either
port for either protocol.
External Loopback Via Jumpers
To evaluate the Rx and Tx performance at the same time, an
external loopback can be implemented simply by installing
jumpers “A1/Y1_LB”
jumpers “A2/Y2_LB”
this configuration, the Tx output lines connect to the
corresponding Rx input lines, so the data driven on the Tx
input(s) appears at the Rx output(s). In RS-485 mode, data
driven on DY loops back through A and B to R
mode, DY loops back to R
Basic RS-485 DC Evaluation (Port 2)
GENERAL OBSERVATIONS
I
due to the RS-485 Tx driving the 120Ω termination resistor
(R13). To get just the quiescent ISL3333 I
jumper “DE2”
approximately 3.9mA, due to the charge pumps running to
provide the RS-232 transmitter supplies for Port 1. Move
jumper “DE2” back to the “VH” position.
Measure V+ and V- at the banana jacks - V+ ≈ +6V and
V- ≈ -5.7V, indicating that the charge pumps are on. If both
ports were programmed for RS-485 mode, then I
1.2mA (if “DE2” = “LOW”), and V+ ≈ V
RA2 is high (due to the “full failsafe” Rx) while RB2 is
tri-stated, but pulled high by a weak internal current source,
because it is unused in RS-485 mode.
RECEIVER TESTS
The “full failsafe” nature of the Rx can be evaluated by
manipulating the “A2 (485/232)”
jumpers. In the default configuration, A2 and B2 are
“shorted” via a 120Ω termination resistor, but RA2 (measure
at the “RA2 (NC)” test point, located between test points
“TP17” and “TP21”) remains high due to the failsafe
“terminated but undriven” functionality. Installing jumpers
“A2”
the two inputs together (i.e., V
CC
should be approximately 23mA. Most of this current is
(14)
OH
(to the “LOW” position) and “B2” effectively shorts
(26)
levels, and the logic and Tx input switching
(19)
and “VL-VHIGH”
to the "LOW" position. I
(5)
(10)
(26)
and “B1/Z1_LB”
and “B2/Z2_LB”
jumper shorts this jack to V
A
, and DZ loops back to R
ID
(27)
(14)
= V
B2
jumpers are installed in
and “B2”
CC
- V
(6)
, V- = GND.
CC
CC
A2
(9)
for Port 1, and
, simply move
= 0). RA2 still
should now be
for Port 2. In
A
(13)
. In RS-232
CC
input
June 3, 2009
drops to
B
CC
AN1470.0
.
CC
, so
CC
CC
.