19-2512; Rev 1; 9/03
1ꢀ5k ꢁEDꢂ-rotected TouchꢂEcreen
Controllers Include DAC and Keypad Controller
General Description
Features
The MAX1233/MAX1234 are complete PDA controllers in
a 5mm × 5mm, 28-pin QFN package. They feature a
12-bit analog-to-digital converter (ADC), low on-resis-
tance switches for driving resistive touch screens, an
internal +1.0V/+2.5V or external reference, 2°C accu-
rate, on-chip temperature sensor, direct +6V battery mon-
itor, keypad controller, 8-bit digital-to-analog converter
(DAC), and a synchronous serial interface. Each of the
keypad controllers’ eight row and column inputs can be
reconfigured as general-purpose parallel I/O pins (GPIO).
All analog inputs are fully ESD protected, eliminating the
need for external TransZorb™ devices.
o ESD-Protected Analog Inputs
15kV IEC 1000-4-2 Air-Gap Discharge
8kV IEC 1000-4-2 Contact Discharge
o Single-Supply Operation
+2.7V to +3.6V (MAX1233)
+4.75V to +5.25V (MAX1234)
o 4-Wire Touch-Screen Interface
o Internal +1.0V/+2.5V Reference or External
Reference (+1.0V to AV
)
DD
o SPI™/QSPI™/MICROWIRE™-Compatible 10MHz
The MAX1233/MAX1234 offer programmable resolution
and sampling rates. Interrupts from the devices alert the
host processor when data is ready, when the screen is
touched, or a key press is detected. Software-
configurable scan control and internal timers give the user
flexibility without burdening the host processor. These
devices consume only 260µA at the maximum sampling
rate of 50ksps. Supply current falls to below 50µA for
sampling rates of 10ksps. The MAX1233/MAX1234 are
guaranteed over the -40°C to +85°C temperature range.
Serial Interface
o 12-Bit, 50ksps ADC Measures
Resistive Touch-Screen Position and Pressure
Two Auxiliary Analog Inputs
Two Battery Voltages (0.5V to 6V)
On-Chip Temperature
o 8-Bit DAC for LCD Bias Control
o 4 × 4 Keypad Programmable Controller Offers Up
to Eight GPIO Pins
Applications
o Automatic Detection of Screen Touch, Key Press,
Personal Digital Assistants
and End of Conversion
Pagers
o Programmable 8-, 10-, 12-Bit Resolution
o Programmable Conversion Rates
Touch-Screen Monitors
Cellular Phones
o AutoShutdown™ Between Conversions
MP3 Players
Portable Instruments
Point-of-Sale Terminals
o Low Power
260µA at 50ksps
50µA at 10ksps
6µA at 1ksps
-in Configuration
0.3µA Shutdown Current
TOP VIEW
o 28-Pin 5mm × 5mm QFN Package
Ordering Information
DV
AV
1
2
3
4
5
6
7
21 C4
20 C3
19 C2
18 C1
17 R1
16 R2
15 R3
DD
DD
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
*X+
*Y+
*X-
MAX1233
MAX1234
MAX1233EGI
MAX1234EGI
28 QFN (5mm × 5mm)
28 QFN (5mm × 5mm)
*Y-
GND
TransZorb is a trademark of General Semiconductor Industries,
Inc.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
QFN
*PIN INCLUDES 8kV/15kV ESD PROTECTION.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.