MAX3111EEWI+TG36 Maxim Integrated Products, MAX3111EEWI+TG36 Datasheet - Page 24

• Manufacturer Part Number: MAX3111EEWI+TG36
• Description: IC UART SPI COMPAT 28-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of MAX3111EEWI+TG36

• Features: Transceiver
• Number Of Channels: 1, UART
• Protocol: RS232, RS485
• Voltage - Supply: 3 V ~ 3.6 V
• With Irda Encoder/decoder: Yes
• With False Start Bit Detection: Yes
• With Cmos: Yes
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Ceramic resonators are low-cost alternatives to crystals
and operate similarly, although the Q and accuracy are
lower. Some ceramic resonators are available with inte-
gral load capacitors, which can further reduce cost. The
tradeoff between crystals and ceramic resonators is in
initial-frequency accuracy and temperature drift. Keep
the total error in the baud-rate generator below 1% for
reliable operation with other systems. This is accom-
plished easily with a crystal and, in most cases, is
achieved with ceramic resonators. Table 8 lists different
types of crystals and resonators and their suppliers.
The MAX3110E/MAX3111E’s oscillator supports paral-
lel-resonant mode crystals and ceramic resonators or
can be driven from an external clock source. Internally,
the oscillator consists of an inverting amplifier with its
input, X1, tied to its output, X2, by a bias network that
self-biases the inverter at approximately V
external feedback circuit, usually a crystal from X2 to X1,
provides 180° of phase shift, causing the circuit to oscil-
late. As shown in the Standard Application Circuit, the
crystal or resonator is connected between X1 and X2,
with the load capacitance for the crystal being the
series combination of C1 and C2. For example, for a
1.8432MHz crystal with a specified load capacitance of
11pF, use capacitors of 22pF on either side of the crystal
to ground. Series-resonant mode crystals have a slight
frequency error, typically oscillating 0.03% higher than
SPI/MICROWIRE-Compatible UART and ±15kV ESD-
Protected RS-232 Transceivers with Internal Capacitors
Table 8. Component and Supplier List
24
Through-Hole Crystal
(HC-49/U)
Through-Hole
Ceramic Resonator
Through-Hole Crystal
(HC-49/US)
SMT Crystal
SMT Ceramic
Resonator
DESCRIPTION
______________________________________________________________________________________
FREQUENCY
1.8432
1.8432
3.6864
3.6864
3.6864
(MHz)
C1, C2 (pF)
TYPICAL
CC
(integral)
None
25
47
33
39
/2. The
ECS International, Inc.
Murata North America
ECS International, Inc.
ECS International, Inc.
AVX/Kyocera
specified series-resonant frequency when operated in
parallel mode.
Note: It is very important to keep crystal, resonator, and
load-capacitor leads and traces as short and direct as
possible. Make the X1 and X2 trace lengths and ground
tracks short, with no intervening traces. This helps mini-
mize parasitic capacitance and noise pickup in the
oscillator, and reduces EMI. Minimize capacitive load-
ing on X2 to minimize supply current. The MAX3110E/
MAX3111E’s X1 input can be driven directly by an
external CMOS clock source. The trip level is approxi-
mately equal to V
mode. If a TTL or non-CMOS clock source is used, AC-
couple it with a 10nF capacitor to X1. A 2V peak-to-
peak swing on the input is required for reliable
operation.
Figure 7 shows two RS-232 transmitter outputs exiting
shutdown mode. As they become active, the two trans-
mitter outputs are shown going to opposite RS-232 lev-
els (one transmitter input is high; the other is low). Each
transmitter is loaded with 3kΩ in parallel with 2500pF.
The transmitter outputs display no ringing or undesir-
able transients as they come out of shutdown. Note that
the transmitters are enabled only when the magnitude
of V- exceeds approximately 3V.
SUPPLIER
CC
RS-232 Transmitter Outputs
/2. Make no connection to X2 in this
ECS-18-13-1
CSA1.84MG
ECS-36-18-4
ECS-36-20-5P
PBRC-3.68B
NUMBER
PART
Exiting Shutdown
913-782-7787
800-831-9172
913-782-7787
913-782-7787
803-448-9411
NUMBER
PHONE