MAX3320A Datasheet, PDF (1/12 Pages) Maxim Integrated Products – 3V to 5.5V, up to 250kbps True RS-232 Transceiver with 4μA AutoShutdown Plus and Power-On Reset

19-1253; Rev 0; 8/97
3V to 5.5V, up to 250kbps True RS-232 Transceiver
with 4µA AutoShutdown Plus and Power-On Reset
_______________General Description
The MAX3320 combines a microprocessor (µP) super-
visory circuit with an RS-232 transceiver. The power-on
reset performs a single function: it asserts a reset signal
whenever the V_CC supply voltage declines below a pre-
set threshold, staying asserted for at least 100ms after
V_CC rises above the reset threshold. The MAX3320 has
an active-low RESET output, which is guaranteed to be in
the correct state for V_CC down to 1V. The reset compara-
tor is designed to ignore fast transients on V_CC. Reset
thresholds suitable for operation with a variety of supply
voltages are available.
The MAX3320 transceivers have a proprietary low-
dropout transmitter output stage, enabling true RS-232
performance with a dual charge pump powered from a
+3V to +5.5V supply. The device requires only four
small 0.1µF external charge-pump capacitors, and is
guaranteed to run at data rates of up to 250kbps. It
comes in the space-saving 20-pin SSOP package.
________________________Applications
Palmtop Computers
Portable/Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers
____________________________Features
o Precise Monitoring of 5V and 3.3V Power-
Supply Voltages:
— 100ms (min) Power-On RESET Pulse Width
— Power-Supply Transient Immunity
— Guaranteed RESET Valid to V_CC = 1V
o 4µA Supply Current Achieved with
AutoShutdown Plus
o Receivers Always Active
o Power-On Reset Always Active
o 4µA Low-Power Shutdown
o 250kbps Guaranteed Data Rate
______________Ordering Information
PART*
MAX3320_CAP
MAX3320_EAP
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
20 SSOP
20 SSOP
* This part offers a choice of reset threshold voltage. From the
table below, select the suffix corresponding to the desired
threshold and insert it into the blank to complete the part
number.
__________________Pin Configuration
TOP VIEW
V+ 1
C2+ 2
C2- 3
V- 4
T1IN 5
T2IN 6
R1OUT 7
R2OUT 8
INVALID 9
RESET 10
MAX3320
MAXxxx
20 C1+
19 V_CC
18 C1-
17 GND
16 T1OUT
15 T2OUT
14 R1IN
13 R2IN
12 FORCEON
11 FORCEOFF
SUFFIX
A
B
L
T
RESET THRESHOLD
(V)
4.25
2.85
4.63
3.08
Typical Operating Circuit appears at end of data sheet.
SSOP
AutoShutdown Plus is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products 1
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For small orders, phone [phone] ext. 3468.