General Description
The MAX13235E evaluation kit (EV kit) provides a
proven design to evaluate the MAX13235E, a 3Mbps
RS-232 transceiver with low-voltage interface and
enhanced electrostatic discharge (ESD) protection.
This EV kit demonstrates the MAX13235E in a 20-pin
TSSOP package. The MAX13235E is also available in a
20-pin TQFN package with an exposed pad, but that
package is not compatible with this EV kit.
The MAX13235E EV kit PCB comes with a MAX13235EEUP+
installed, which is the 3Mbps data-rate version. The
MAX13235E EV kit can also be used to evaluate the
MAX13234E (250kbps data-rate version). Contact the
factory for free samples of the pin-compatible
MAX13234EEUP+ to evaluate this device.
Features
o3V to 5.5V Single-Supply Operation
o3Mbps RS-232 Data Rate
oLow-Voltage Logic Interface
oDigital Loopbacks
oRS-232 Loopbacks
oLead(Pb)-Free and RoHS Compliant
oProven PCB Layout
oFully Assembled and Tested
Evaluates: MAX13234E/MAX13235E
MAX13235E Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
19-4545; Rev 0; 4/09
Component List
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
Component Suppliers
DESIGNATION QTY DESCRIPTION
C1, C2 2
10_F ±20%, 16V X5R ceramic
capacitors (1206)
Murata GRM31CR61C106M
C3–C6 4
0.1_F ±10%, 16V X7R ceramic
capacitors (0603)
TDK C1608X7R1C104K
J1 1 Female RS-232 DB9 connector
J2 1 Dual-row (2 x 4) 8-pin header
DESIGNATION QTY DESCRIPTION
JU1–JU4 4 3-pin headers
JU5, JU6 2 2-pin headers
U1 1
3Mbsp RS-232 transceiver
(20 TSSOP)
Maxim MAX13235EEUP+
— 6 Shunts
— 1 PCB: MAX13235E EVALUATION KIT+
SUPPLIER PHONE WEBSITE
Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com
TDK Corp. 847-803-6100 www.component.tdk.com
PART TYPE
MAX13235EEVKIT+ EV Kit
+
Denotes lead(Pb)-free and RoHS compliant.
Note: Indicate that you are using the MAX13235E when contacting these component suppliers.
Evaluates: MAX13234E/MAX13235E
MAX13235E Evaluation Kit
2 _______________________________________________________________________________________
Figure 1. RealTerm Software Main Window (Port Tab)
Quick Start
Recommended Equipment
• MAX13235E EV kit
• DB9 I/O extension cable included
• Two 5V/100mA DC power supplies
• User-supplied Windows®2000/XP®or Windows
Vista®PC with a spare RS-232 serial port
Note: In the following sections, software-related items
are identified by bolding. Text in bold refers to items
directly from the EV kit software. Text in bold and
underlined refers to items from the Windows operating
system.
Procedure
The MAX13235E EV kit is fully assembled and tested.
Follow the steps below to verify the board operation.
Caution: Do not turn on power supply until all con-
nections are made.
1) Visit www.maxim-ic.com/evkitsoftware to down-
load the latest version of the EV kit software,
13235Rxx.ZIP. Save the EV kit software to a tempo-
rary folder and uncompress the ZIP file. The EV kit
software consists of the free, open-source terminal
emulator, RealTerm (also available from http://real-
term.sourceforge.net).
2) Verify that shunts are installed across pins 1-2 of
jumpers JU1 and JU2 to enable normal operation.
3) Verify that shunts are installed across pins 1-3 and
pins 5-7 of the J2 connector to enable the digital
loopback.
4) Verify that shunts are not installed on jumpers
JU3–JU6.
5) Connect the positive terminal of the first 5V supply
to the VCC pad. Connect the negative terminal of
the first 5V supply to the GND pad.
6) Connect the positive terminal of the second 5V sup-
ply to the VL pad. Connect the negative terminal of
the second 5V supply to the GND pad.
Windows, Windows XP, and Windows Vista are registered trademarks of Microsoft Corp.
Evaluates: MAX13234E/MAX13235E
MAX13235E Evaluation Kit
_______________________________________________________________________________________ 3
JUMPER SIGNAL SHUNT POSITION DESCRIPTION
1-2* FORCEON = VL
JU1 FORCEON 2-3 FORCEON = GND
1-2* FORCEOFF = VL
JU2 FORCEOFF
2-3 FORCEOFF = GND
Open* T1IN connects to pin 1 of J2 connector
1-2 T1IN = VL
JU3 T1IN
2-3 T1IN = GND
Open* T2IN connects to pin 7 of J2 connector
1-2 T2IN = VLJU4 T2IN
2-3 T2IN = GND
1-2 R1IN is driven by T1OUT from U1. Data received from digital side
loops back at RS-232 connection.
JU5
Open* R1IN is not connected to T1OUT
1-2 R2IN is driven by T2OUT from U1. Data received from digital side
loops back at RS-232 connection.
JU6
RS-232 Loopback
Open* R2IN is not connected to T2OUT
1-3 T1IN is driven by R1OUT from U1. Data received from RS-232 side
loops back at digital connection.
Open* T1IN is not connected to R1OUT
5-7 T2IN is driven by R2OUT from U1. Data received from RS-232 side
loops back at digital connection.
J2 Digital Loopback
Open* T2IN is not connected to R2OUT
Table 1. MAX13235E EV Kit Jumper Descriptions
7) Connect the DB9 I/O extension cable between the
EV kit and the computer’s serial port.
8) Start the RealTerm software by opening its icon in
the Start | Programs menu. The RealTerm software
main window appears, as shown in Figure 1. Note:
If the serial cable is connected to a serial port other
than COM1, bring up the Port tab and open the
corresponding serial port.
9) In the RealTerm window, click in the display area
and type on the keyboard. The digital loopback
connection immediately relays each character from
the receiver to the transmitter, so each character
typed on the keyboard appears in the display area.
10) Move the shunt on jumper JU2 to pins 2-3 to dis-
able the MAX13235E.
11) In the RealTerm window, click in the display area
and type on the keyboard. With the MAX13235E
disabled, characters typed on the keyboard do not
appear in the display area.
Detailed Description of Hardware
The MAX13235E EV kit provides a proven design to
evaluate the MAX13235E, a 3Mbps RS-232 transceiver
with low-voltage interface and enhanced ESD protec-
tion. Capacitors C3–C6 are used by the charge pump
to generate the V+ and V- supplies from VCC.
Header J2 provides the digital connections to the
MAX13235E. Header J2 also allows digital loopback by
placing shunts across pins 1-3 and 5-7.
Jumpers
Jumpers JU1 and JU2 control the MAX13235E power-
management signals. Jumpers JU3 and JU4 can be
used to set the logic level of T1IN and T2IN. Jumpers
JU5 and JU6 allow RS-232 loopback.
EV Kit I/O Connections
The MAX13235E EV kit features a dual-row (2 x 4) 8-pin
header (J2) for interfacing with logic signals. The J2
header and a DB9 connector (J1) are available to inter-
face with an RS-232 serial line.
*
Default position.
Evaluates: MAX13234E/MAX13235E
MAX13235E Evaluation Kit
4 _______________________________________________________________________________________
Figure 2. MAX13235E EV Kit Schematic
Evaluates: MAX13234E/MAX13235E
MAX13235E Evaluation Kit
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________
5
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Figure 3. MAX13235E EV Kit Component Placement Guide Figure 4. MAX13235E EV Kit PCB Layout—Component Side
Figure 5. MAX13235E EV Kit PCB Layout—Solder Side
