19-1253; Rev 0; 8/97
3V to 5.5V, up to 250kbps True RS-232 Tra ns c e ive r
w ith 4µA AutoShutdow n Plus a nd Pow e r-On Re s e t
MX320ABL/T
_______________Ge n e ra l De s c rip t io n
____________________________Fe a t u re s
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
♦ Precise Monitoring of 5V and 3.3V Power-
Supply Voltages:
— 100ms (min) Power-On RESET Pulse Width
— Power-Supply Transient Immunity
whenever the V supply voltage declines below a pre-
CC
set threshold, staying asserted for at least 100ms after
— Guaranteed RESET Valid to V = 1V
CC
V
CC
rises above the reset threshold. The MAX3320 has
an active-low RESET output, which is guaranteed to be in
♦ 4µA Supply Current Achieved with
the correct state for V down to 1V. The reset compara-
CC
AutoShutdown Plus
tor is designed to ignore fast transients on V . Reset
CC
♦ Receivers Always Active
thresholds suitable for operation with a variety of supply
voltages are available.
♦ Power-On Reset Always Active
♦ 4µA Low-Power Shutdown
♦ 250kbps Guaranteed Data Rate
The MAX3320 tra nsc e ive rs ha ve a p roprie ta ry 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.
______________Ord e rin g In fo rm a t io n
________________________Ap p lic a t io n s
Palmtop Computers
PART*
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
20 SSOP
Portable/Battery-Powered Equipment
Hand-Held Equipment
MAX3320_CAP
MAX3320_EAP
-40°C to +85°C
20 SSOP
Peripherals
* 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.
Printers
__________________P in Co n fig u ra t io n
RESET THRESHOLD
SUFFIX
(V)
A
B
L
T
4.25
2.85
4.63
3.08
TOP VIEW
V+
C2+
1
2
3
4
5
6
7
8
9
20 C1+
19
V
CC
C2-
18 C1-
V-
17 GND
MAX3320
MAXxxx
T1IN
16 T1OUT
15 T2OUT
14 R1IN
T2IN
Typical Operating Circuit appears at end of data sheet.
R1OUT
R2OUT
INVALID
13 R2IN
12 FORCEON
11 FORCEOFF
RESET 10
SSOP
AutoShutdown Plus is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.