MAX3318EEUP+ Maxim Integrated Products, MAX3318EEUP+ Datasheet - Page 7

• Manufacturer Part Number: MAX3318EEUP+
• Description: IC TXRX RS232 460KBPS 20-TSSOP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3318EEUP+

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 2.25 V ~ 3 V
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX3316–MAX3319s’ internal power supply con-
sists of a regulated dual charge pump that provides
output voltages of +4.4V (doubling charge pump) and
-4.3V (inverting charge pump), over the +2.25V to
+3.0V input voltage range. The charge pump operates
in discontinuous mode: if the output voltages are less
than 4.4V, the charge pump is enabled; if the output
voltages exceed 4.4V, the charge pump is disabled.
Each charge pump requires a flying capacitor (C1, C2)
and a reservoir capacitor (C3, C4) to generate the V+
and V- supplies.
The READY output (MAX3318/MAX3319) is low when
the charge pumps are disabled in shutdown mode. The
READY signal asserts high when V- goes below -2.75V.
The MAX3316–MAX3319s’ transmitters are inverting
level translators that convert CMOS-logic levels to
RS-232-compatible voltage levels. They guarantee a
460kbps data rate with worst-case loads of 3kΩ in parallel
with 1000pF, providing compatibility with PC-to-PC
communication software (such as LapLink™).
The MAX3317’s transmitters are turned off (high imped-
ance) when SHDN is asserted low, putting the device in
shutdown mode. The MAX3318/MAX3319s’ transmitters
LapLink is a trademark of Traveling Software.
SSOP
—
—
—
—
—
MAX3316
Dual Charge-Pump Voltage Converter
RS-232-Compatible Transmitters
TSSOP
—
—
—
—
—
_______________________________________________________________________________________
Detailed Description
MAX3317
TSSOP
SSOP/
PIN
20
—
—
—
—
MAX3318
RS-232-Compatible Transceivers
TSSOP
SSOP/
11
14
20
—
1
MAX3319
SSOP
10
12
16
—
1
FORCEOFF
FORCEON
INVALID
READY
are turned off (high impedance) when FORCEOFF is
asserted low, or when the AutoShutdown Plus circuitry
senses that all receiver and transmitter inputs are inac-
tive for more than 30 seconds.
The transmitter outputs can be driven to ±12V when
power is off. The transmitter inputs do not have internal
pullup resistors. Connect unused inputs to GND or V
Figure 1a shows an RS-232-compatibility circuit and
Figure 1b shows MAX3316–MAX3319 transmitter output
compatibility with an RS-232 receiver.
The MAX3316–MAX3319s’ receivers convert RS-232
signal levels into CMOS-logic output levels. The
receivers are rated to receive signals up to ±25V. The
MAX3316/MAX3318/MAX3319s’ receivers feature
inverting outputs that always remain active (Table 1).
The MAX3317’s receivers have inverting, three-state
outputs. In shutdown, the receivers can be active or
inactive (Table 2).
The MAX3318/MAX3319 feature an INVALID output that
is asserted low when no valid RS-232 voltage levels
have been detected on all receiver inputs. Because
INVALID indicates the receiver’s input condition, it
is independent of the states of FORCEON and
FORCEOFF.
NAME
SHDN
2.5V, 1µA, 460kbps,
Shutdown Control, Active Low
Ready to Transmit Output, Active High. READY is
enabled high when V- goes below -2.75V and the
device is ready to transmit.
Valid Signal Detector Output, Active Low. A logic
high indicates that a valid RS-232 level is present
on a receiver input.
Force-On Input, Active High. Drive high to override
AutoShutdown Plus, keeping transmitters and
receivers on (FORCEOFF must be high) (Table 1).
Force-Off Input, Active Low. Drive low to shut
down transmitters, receivers, and charge pump.
This overrides AutoShutdown Plus and FORCEON
(Table 1).
Pin Description (continued)
FUNCTION
RS-232 Receivers
CC
.
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