MAXIM MAX3325 3V Dual RS-232 Transceiver with LCD Supply and Contrast Controller
Summary
This integrated circuit is a specialized dual RS-232 transceiver designed specifically for small, low-voltage 3V embedded systems that require precise LCD display control. The MAX3325 manages both serial data communication and provides an optimized power supply and temperature-compensated contrast adjustment for typical LCD modules. The associated manual details the device's complex functions—including regulated 5V output, internal digital-to-analog conversion (DAC), and automatic bias adjustment across extreme temperatures—guiding engineers in integrating reliable communication and display capabilities into portable devices such as hand-held terminals or medical equipment.
Page 1 Text Content
19-1573; Rev 0; 10/99
3V Dual RS-232 Transceiver with LCD Supply and Contrast Controller General Description Features
The MAX3325 integrates a two-transmitter, two-receiver +3.0V to +3.6V Single-Supply Operation RS-232 transceiver with an LCD supply plus tempera-
Provides 5.0V Regulated Output at 11m A in
ture-compensated contrast control. It is intended for
3V Systems
small 3V instruments requiring a 5V supply for either
logic or an LCD display, an adjustable bias signal for 6-Bit DAC with Up/Down Interface for LCD contrast, LCD temperature compensation, and an Contrast Adjustment
RS-232 interface for serial communications.
Selectable Positive or Negative LCD Bias
The 5V supply is a regulated charge pump followed by
Meets EIA-232E Specifications at 250kbps—
a low-dropout (LDO) linear regulator capable of supply-
Guaranteed
ing 11m A for the 5V LCD power.
1µA Shutdown Mode
The MAX3325 has an internal 6-bit digital-to-analog
converter (DAC) providing 64 contrast levels, plus an Uses Small 0.22µF Capacitors—No Inductors internal temperature sensor that compensates the Required
LCD’s contrast for changes in ambient temperature.
Temperature Sensor for LCD Contrast
The LCD contrast can be designed for any voltage
Compensation
range from -5V to +2V.
Simple, Flexible Design Procedure for a Broad
The MAX3325’s 250kbps RS-232 transceiver meets all
Range of LCD Displays
EIA-232E specifications with input voltages from +3.0V to +3.6V. Both the RS-232 section and the LCD supply
Ordering Information
circuitry can be independently placed in shutdown, tai- loring power consumption for battery-powered equip-
PART TEMP. RANGE PIN-PACKAGE
ment. The MAX3325 is available in 28-pin SSOP and
MAX3325CAI 0°C to +70°C 28 SSOP
narrow DIP packages.
MAX3325CNI 0°C to +70°C 28 Narrow Plastic DIP MAX3325EAI -40°C to +85°C 28 SSOP MAX3325ENI -40°C to +85°C 28 Narrow Plastic DIP
Pin Configuration
Applications
PDAs and Palmtop Computers
TOP VIEW
Handy Terminals
GPS Receivers
Hand-Held Medical Equipment
V- VDD
Industrial Test Equipment
R2IN GND
R1IN C1-
MAX3325
R1OUT REG
R2OUT T1OUT
VL T2OUT
LCD T1IN
TEMP T2IN
REF- SD232
FB SDLCD
REF+ DOWN
DAC UP
Typical Operating Circuit appears at end of data sheet.
SSOP/DIP
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769.
Page Summary Contents For MAXIM MAX3325 3V Dual RS-232 Transceiver with LCD Supply and Contrast Controller
Manual Details
| Brand | Dual |
|---|---|
| Pages | 12 |
| File Size | 127.06 KB |
| Published | May 30, 2026 |
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