MAX3325CAI-T Maxim Integrated, MAX3325CAI-T Datasheet

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MAX3325CAI-T

Manufacturer Part Number
MAX3325CAI-T
Description
RS-232 Interface IC
Manufacturer
Maxim Integrated
Series
MAX3325r
Datasheet

Specifications of MAX3325CAI-T

Data Rate
250 Kbps
Operating Supply Voltage
3 V to 3.6 V
Supply Current
2 mA
Operating Temperature Range
- 40 C to + 85 C
Number Of I/os
2 / 2
Propagation Delay Time Ns
300 ns
The MAX3325 integrates a two-transmitter, two-receiver
RS-232 transceiver with an LCD supply plus tempera-
ture-compensated contrast control. It is intended for
small 3V instruments requiring a 5V supply for either
logic or an LCD display, an adjustable bias signal for
contrast, LCD temperature compensation, and an
RS-232 interface for serial communications.
The 5V supply is a regulated charge pump followed by
a low-dropout (LDO) linear regulator capable of supply-
ing 11mA for the 5V LCD power.
The MAX3325 has an internal 6-bit digital-to-analog
converter (DAC) providing 64 contrast levels, plus an
internal temperature sensor that compensates the
LCD’s contrast for changes in ambient temperature.
The LCD contrast can be designed for any voltage
range from -5V to +2V.
The MAX3325’s 250kbps RS-232 transceiver meets all
EIA-232E specifications with input voltages from +3.0V
to +3.6V. Both the RS-232 section and the LCD supply
circuitry can be independently placed in shutdown, tai-
loring power consumption for battery-powered equip-
ment. The MAX3325 is available in 28-pin SSOP and
narrow DIP packages.
Typical Operating Circuit appears at end of data sheet.
19-1573; Rev 0; 10/99
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.
PDAs and Palmtop Computers
Handy Terminals
GPS Receivers
Hand-Held Medical Equipment
Industrial Test Equipment
________________________________________________________________ Maxim Integrated Products
General Description
LCD Supply and Contrast Controller
Applications
3V Dual RS-232 Transceiver with
MAX3325CAI
MAX3325CNI
MAX3325EAI
MAX3325ENI
+3.0V to +3.6V Single-Supply Operation
Provides 5.0V Regulated Output at 11mA in
3V Systems
6-Bit DAC with Up/Down Interface for LCD
Contrast Adjustment
Selectable Positive or Negative LCD Bias
Meets EIA-232E Specifications at 250kbps—
Guaranteed
1µA Shutdown Mode
Uses Small 0.22µF Capacitors—No Inductors
Required
Temperature Sensor for LCD Contrast
Compensation
Simple, Flexible Design Procedure for a Broad
Range of LCD Displays
TOP VIEW
PART
R1OUT
R2OUT
TEMP
REF+
R2IN
R1IN
REF-
DAC
LCD
C2+
C2-
FB
V
V-
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
L
0°C to +70°C
0°C to +70°C
10
11
12
13
14
1
2
3
4
5
6
7
8
9
Ordering Information
SSOP/DIP
MAX3325
Pin Configuration
28 SSOP
28 Narrow Plastic DIP
28 SSOP
28 Narrow Plastic DIP
PIN-PACKAGE
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C1+
V+
V
GND
C1-
REG
T1OUT
T2OUT
T1IN
T2IN
SD232
SDLCD
DOWN
UP
DD
Features
1

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MAX3325CAI-T Summary of contents

Page 1

... Uses Small 0.22µF Capacitors—No Inductors Required Temperature Sensor for LCD Contrast Compensation Simple, Flexible Design Procedure for a Broad Range of LCD Displays Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX3325CAI 0°C to +70°C 28 SSOP MAX3325CNI 0°C to +70°C 28 Narrow Plastic DIP MAX3325EAI -40°C to +85°C 28 SSOP MAX3325ENI -40° ...

Page 2

Dual RS-232 Transceiver with LCD Supply and Contrast Controller ABSOLUTE MAXIMUM RATINGS GND ........................................................-0. LCD, REF-, TEMP to GND .............................- GND (Note 1) ..................................................-0.3V to +7V V- ...

Page 3

Dual RS-232 Transceiver with LCD Supply and Contrast Controller ELECTRICAL CHARACTERISTICS (continued +3.0V to +3.6V +3.3V, circuit and components of Figure are +3.3V +25°C ...

Page 4

Dual RS-232 Transceiver with LCD Supply and Contrast Controller TIMING CHARACTERISTICS (V = +3.0V to +3.6V +3.3V, circuit and components of Figure are +3.3V +25°C PARAMETER ...

Page 5

Dual RS-232 Transceiver with LCD Supply and Contrast Controller ( +3.3V, circuit and components of Figure 1, all transmitters loaded with 3kΩ and TRANSMITTER OUTPUTS EXITING SHUTDOWN OR POWERING UP MAX3325toc04 5V/div SD232 ...

Page 6

Dual RS-232 Transceiver with LCD Supply and Contrast Controller PIN NAME 1 C2+ Positive Terminal of Voltage-Inverting Charge-Pump Capacitor. Connect C2+ to C2- with a 0.22µF capacitor. 2 C2- Negative Terminal of Voltage-Inverting Charge-Pump Capacitor. Connect C2- to C2+ ...

Page 7

Dual RS-232 Transceiver with LCD Supply and Contrast Controller 0.22 F R1OUT 0.22 F R2OUT *RESISTORS R + AND R - ARE BOTH SHOWN, BUT ONLY ...

Page 8

Dual RS-232 Transceiver with LCD Supply and Contrast Controller Detailed Description Dual Charge-Pump Voltage Converter The MAX3325’s internal power supply consists of a reg- ulated dual charge pump that provides output voltages of +5.5V (doubling charge pump) and -5.5V ...

Page 9

Dual RS-232 Transceiver with LCD Supply and Contrast Controller Applications Information Capacitor Selection The capacitor type used for C1–C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. Ceramic chip capacitors with an X7R dielectric ...

Page 10

Dual RS-232 Transceiver with LCD Supply and Contrast Controller to maintain the nominal contrast is -16mV/°C. In this case, data for a spread of nominal bias voltages is not avail- able range of ±1V is chosen by ...

Page 11

Dual RS-232 Transceiver with LCD Supply and Contrast Controller V- 0.22 F MAX3325 C1+ 0.22 F C1 INPUT DD UP 6-BIT DOWN DAC SDLCD SD232 T1IN TTL/CMOS INPUTS T2IN V L R1OUT TTL/CMOS OUTPUTS ...

Page 12

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products ...

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