Datasheet

MAX218
1.8V to 4.25V-Powered,
True RS-232 Dual Transceiver
_______________________________________________________________________________________ 3
TIMING CHARACTERISTICS
(Circuit of Figure 1, V
CC
= 1.8V to 4.25V, C1 = 0.47µF, C2 = C3 = C4 = 1µF, L1 = 15µH, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at V
CC
= 3.0V, T
A
= +25°C.)
1000pF || 3kΩ load each transmitter,
150pF load each receiver
T
A
= +25°C, V
CC
= 3.0V, R
L
= 3kΩ to 7kΩ,
C
L
= 50pF to 2500pF, measured from
+3V to -3V or -3V to +3V
2500pF || 3kΩ load
150pF load
150pF load
2500pF || 3kΩ load
CONDITIONS
ns200 500t
DR
Receiver Output Disable Time
ns90 300t
ER
kbps120Data Rate
Receiver Output Enable Time
V/µs3.0 30Transition Region Slew Rate
1.8 2.7t
PLHT
Transmitter Propagation Delay
µs140 450t
ET
Transmitter Output Enable Time
ns
290 700t
PHLR
260 700t
PLHR
Receiver Propagation Delay
µs
1.9 2.7t
PHLT
UNITS
MIN TYP MAX
SYMBOLPARAMETER
ns500t
DT
Transmitter Output Disable Time
______________________________________________________________Pin Description
Receiver InputsR2IN, R1IN11, 12
Transmitter Outputs; swing between V+ and V-.T2OUT, T1OUT13, 14
Negative Supply generated on-boardV-15
Terminals for Negative Charge-Pump CapacitorC1-, C1+16, 18
Positive Supply generated on-boardV+19
Ground. Connect all GND pins to ground.GND5, 17, 20
Supply Voltage Input; 1.8V to 4.25V. Bypass to GND with at least 1µF. See Capacitor
Selection section.
V
CC
6
Transmitter InputsT1IN, T2IN7, 8
Receiver Outputs; swing between GND and V
CC.
R1OUT, R2OUT9, 10
Receiver Output Enable Control. Connect to V
CC
for normal operation. Connect to GND to
force the receiver outputs into high-Z state.
EN4
Shutdown Control. Connect to V
CC
for normal operation. Connect to GND to shut down the
power supply and to disable the drivers. Receiver status is not changed by this control.
S
—
H
—
D
—
N
–
3
PIN
Not internally connectedN.C.2
Inductor/Diode Connection PointLX1
FUNCTIONNAME