Datasheet
MAX3320A/B/L/T
3V to 5.5V, up to 250kbps True RS-232 Transceiver
with 4µA AutoShutdown Plus and Power-On Reset
_______________________________________________________________________________________ 5
______________________________________________________________Pin Description
300
0
10 100 1000
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
50
MAX3320toc05
RESET COMPARATOR OVERDRIVE (mV)
MAXIMUM TRANSIENT DURATION (µs)
100
200
150
250
NOT IN
SHUTDOWN
MODE
SHUTDOWN MODE
C
BYPASS
= 0.1µF
0.960
0.970
1.010
1.000
0.990
0.980
1.030
1.020
1.040
-40 0-20 20 40 8060
NORMALIZED POWER-UP RESET
DELAY vs. TEMPERATURE
MAX3320 TOC06
TEMPERATURE (°C)
POWER-UP RESET DELAY
____________________________Typical Operating Characteristics (continued)
(V
CC
= 3.3V, 250kbps data rate, C1–C4 = 0.1µF, all transmitters loaded with 3kΩ. Typical values are at T
A
= +25°C, unless
otherwise noted.)
20 C1+ Positive terminal of voltage-doubler charge-pump capacitor
19 V
CC
+3V to +5.5V Supply Voltage
18 C1- Negative terminal of voltage-doubler charge-pump capacitor
NAME FUNCTION
1 V+ 5.5V generated by the charge pump
2 C2+ Positive terminal of inverting charge-pump capacitor
PIN
3 C2- Negative terminal of inverting charge-pump capacitor
4 V- -5.5V generated by the charge pump
10
RESET
RESET Output. RESET remains low while V
CC
is below the reset threshold, and for 280ms (max)
after V
CC
rises above the reset threshold.
9
INVALID
Output of the Valid Signal Detector. Asserts when no valid RS-232 levels are present on any of
the receiver inputs for 90µs.
7, 8 R_OUT TTL/CMOS Receiver Outputs (R1OUT and R2OUT)
5, 6 T_IN TTL/CMOS Transmitter Inputs (T1IN and T2IN)
17 GND Ground
15, 16 T_OUT RS-232 Transmitter Outputs (T2OUT and T1OUT)
13, 14 R_IN RS-232 Receiver Inputs (R2IN and R1IN)
12 FORCEON
Force-On Input. Drive FORCEON high to override AutoShutdown Plus, keeping transmitters on
(FORCEOFF must be high) (Table 1).
11
FORCEOFF
Force-Off Input. Drive FORCEOFF low to shut down transmitters and on-board power supply.
This overrides AutoShutdown Plus and FORCEON (Table 1).