MAX214CWI+ Maxim Integrated Products, MAX214CWI+ Datasheet - Page 8

• Manufacturer Part Number: MAX214CWI+
• Description: IC TXRX RS232 PROG DTE/DCE28SOIC
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX214CWI+

• Number Of Drivers/receivers: 3/5
• Protocol: RS232
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Data Rate: 116 Kbps
• Interface: RS-232
• Maximum Power Dissipation: 1000 mW
• Minimum Operating Temperature: 0 C
• Supply Current: 9 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

which improves noise margins. The polarity of each
receiver’s input threshold is shown in Tables 1a and 1b.
In normal operating mode, receiver inputs are internally
connected to ground with 5kΩ resistors. So uncon-
nected receivers with positive input thresholds have
high outputs, and those with negative input thresholds
have low outputs.
When shut down, all receivers have positive thresholds.
This allows the receiver inputs to respond to
TTL-/CMOS-logic levels, as well as RS-232 levels. The
guaranteed 0.8V input threshold ensures that receivers
shorted to ground will have a logic 1 output. Also, the
300kΩ input resistance to ground ensures that a receiv-
er with its input left open will also have a logic 1 output.
The receiver’s 0.5V of hysteresis provides clean output
transitions, even with slow rise-time and fall-time sig-
nals with moderate amounts of noise and ringing. The
receivers have no hysteresis in shutdown mode.
The receiver inputs are terminated with 5kΩ resistors, to
comply with the requirements of EIA/TIA-232E.
However, these internal resistors can be disconnected
by taking the HI-Z control pin to a logic high. This
makes all of the MAX214’s receiver inputs high imped-
ance, and facilitates the transmission of RS-232 data
from a single transmitter to multiple receivers. In this
case, all but one of the receiving ICs should be put into
the high input-impedance state.
Programmable DTE/DCE,
+5V RS-232 Transceiver
Table 2. Control Pin Configurations
8
SHUTDOWN
_______________________________________________________________________________________
0
0
0
0
1
1
1
1
CONTROL INPUTS
HI-Z
0
0
1
1
0
0
1
1
DTE/DCE
0
1
0
1
0
1
0
1
HI-Z Control
Transmit Mode
Receive Mode/5k
Transmit Mode
Receive Mode/HI-Z
Disabled/HI-Z
Slow Receive/HI-Z
Disabled/HI-Z
Slow Receive/HI-Z
TRA, TRB, TRC
In shutdown mode, the charge pumps are turned off,
V+ is pulled down to V
the transmitter outputs are disabled. This reduces sup-
ply current typically to 4µA.
shutdown is about 250µs, as shown in Figure 3.
Receiver outputs never go into a high-impedance state;
they are always active, even in shutdown mode (see
Table 2). These awake-in-shutdown receivers are use-
ful for monitoring external activity (for example, on RI),
while maintaining minimal power consumption.
Receivers in shutdown mode are slower (20kbps) than
when not shut down (116kbps), and lack the hysteresis
present in normal operation.
The driver outputs are high impedance in shutdown
mode, even when back-driven with voltages up
to ±15V.
The type of capacitor (C1 to C4) used is not critical for
proper operation. The MAX214 requires 1µF capaci-
tors, although in all cases capacitors of up to 10µF
can be used without harm. Ceramic dielectrics are
suggested for the 1µF capacitors.
__________Applications Information
RTA, RTB, RTC, RDTC
Receive Mode/5k
Transmit Mode
Receive Mode/HI-Z
Transmit Mode
Slow Receive/HI-Z
Disabled/HI-Z
Slow Receive/HI-Z
Disabled/HI-Z
RS-232 PINS
CC
, V- is pulled to ground, and
Capacitor Selection
The time required to exit
Shutdown Control
Receive Mode/5k
Receive Mode/5k
Receive Mode/HI-Z
Receive Mode/HI-Z
Slow Receive/HI-Z
Slow Receive/HI-Z
Slow Receive/HI-Z
Slow Receive/HI-Z
RRE
Receivers
Drivers