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
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 VCC supply voltage declines below a pre-
set threshold, staying asserted for at least 100ms after
VCC rises above the reset threshold. The MAX3320 has
an active-low RESET output, which is guaranteed to be in
the correct state for VCC down to 1V. The reset compara-
tor is designed to ignore fast transients on VCC. 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.
o Precise Monitoring of 5V and 3.3V Power-
— 100ms (min) Power-On RESET Pulse Width
— Power-Supply Transient Immunity
— Guaranteed RESET Valid to VCC = 1V
o 4µA Supply Current Achieved with
o Receivers Always Active
o Power-On Reset Always Active
o 4µA Low-Power Shutdown
o 250kbps Guaranteed Data Rate
0°C to +70°C
-40°C to +85°C
* 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
Typical Operating Circuit appears at end of data sheet.
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.