DEMO CIRCUIT 827
QUICK LTC4260CGN
START GUIDE
LTC2803 and LTC2804
1.8V to 5.5V RS-232 Dual Transceiver
DESCRIPTION
Demons r t on c r i 827 is a 1 to 5
t ai i cu t
.8V
.5V RS-232
Dua T ansce ve f tu i t LTC2803 and LTC2804
l r
i r ea r ng he
.
VERSION
DC827A-A
DC827A-B
P/N
LTC2803CDHC
LTC2804CDHC
Design files for this circuit board are available. Call
the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT and
PowerPath are trademarks of Linear Technology Corporation.
PERFORMANCE SUMMARY
SYMBOL
V
CC
V
L
SR(D)
PARAMETER
Input Supply Voltage
Logic Supply Voltage
Driver Slew Rate
CONDITIONS
MIN
1.8
1.8
4
4
100
250
1000
TYP
MAX
5.5
5.5
30
150
UNITS
V
V
V/µs
V/µs
kbps
kbps
kbps
--
Maximum Data Rate
R
L
=3kΩ, 50pF<C
L
<2.5nF
LTC2803:
LTC2804:
R
L
= 3kΩ, C
L
= 2.5nF
R
L
= 3kΩ, C
L
= 1.0nF
R
L
= 3kΩ, C
L
= 250pF (LTC2804)
JUMPERS
SCH NAME
JP1, MODE,
JP2 PS
PURPOSE
Mode control, as follows:
PS MODE MODE NAME
OFF L
Shutdown
OFF H
Receivers Active
ON L
Drivers Disabled
ON H
Normal
Selects supply for VL pin. Use setting “VL” for a
separate logic supply, or “VCC” to share a single
supply.
Selects Receiver loopback mode, for use with the
DB9 connector. In this configuration, R1OUT is con-
nected to T1IN and R2OUT is connected to T2IN.
SCH NAME
PURPOSE
For the UART connected to the DB9, this wraps TD
back to RD and RTS back to CTS.
JP3
LOGIC
SUPPLY
JP4, TD/RD,
JP5 RTS/CTS
1
QUICK START PROCEDURE
Demons r t on c r i 827is easyto se upfo eva t
t ai i cut
t
r lua -
i the LTC2803 and LTC2804 Re r to F
ng
. fe
igure 1 or
F re 2 fo prope se andfol the procedure be
igu
r
r tup
l ow
-
l :
ow
1.
7.
Check fo the prope gene t supp y vo t
r
r
ra ed
l
l ages:
VDD = 6 to 7 , and VEE = -6 to -5 .
.5V
.5V
.8V
.8V
Send da a
t!
8.
P
lacej
umpersi t f l o
n he ol wing pos t ons
ii :
JP1
JP2
MODE
PS
H
ON
Notes
:
1.
2.
With power o f connec t pr
f,
t he imary power supp y
l
t VCC and GND.
o
Se
JP3
“Log c Supp y t the cor t pos t on I a
t
i
l” o
rec
ii . f
sepa t log c supp y isn’ needed use the “VCC”
ra e i
l
t
,
se t ng I a sepa t Log c Supp wilbe used use
ti . f
ra e i
ly l
,
t “VL” se t ng and w th t power o f connec the
he
ti
, i he
f,
t
supp yt VL and GND.
l o
Fo t
r ransmi t rloopback mode (F re 1) connec
te
igu
,
t
each dr ve ou tto a rece ve inpu . Connec input
i r tpu
i r
t
t
sou
rces to the dr ve inpu .(Make sure tha input
i r
ts
t
vo t
l ages don t exceed 7V ) Omi Loopback jumpers
’
.
t
JP4
and
JP5
fo t i mode
r hs
.
A t rna i l ,to ope t the par inrece ve loopback
l e t ve y
ra e
t
i r
mode (F re 2) connec a 9-w r RS-232 cab e be-
igu
,
t
ie
l
tween DB9 connec r J1 and the se i l por o a
to
ra
t f
compute. P acejumpersi thetwo LOOPBACK po-
r l
n
s tons
ii :
JP4
JP5
TD/RD
CTS/RTS
2.
I ts PS and MODE may be dr ven by s l in
npu
i
igna s -
s ead o se w th jumpers.I done ensure tha the
t
f t i
f
,
t
vo t o PS doesn texceed VL
l age f
’
.
The te ina emu t on program Rea Te can lock
rm l
lai
l rm
up when RTS/CTS f
low con ro i used in rece ve
t ls
i r
l
oopback mode
.
3.
4.
5.
Data may be t
ransmi t d and mon to
te
i red us
ing a
t rm l emu t on program such as Te
e ina
lai
rminal
,
HyperTe ina,T ra Te Pro o Rea Te
rm l e
rm , r l rm.
6.
Tu on the inpu suppl / l es in any orde .
rn
t
y suppi
r
(No : Make sure tha the vo t
te
t
l age doesn t exceed
’
7V )
.
2
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