19-2512; Rev 4; 3/08
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
General Description
The MAX1233/MAX1234 are complete PDA controllers in
5mm
×
5mm, 28-pin QFN and TQFN packages. They fea-
ture a 12-bit analog-to-digital converter (ADC), low on-
resistance 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.
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.
KIT
ATION
EVALU
BLE
AVAILA
Features
♦
ESD-Protected Analog Inputs
±15kV
IEC 1000-4-2 Air-Gap Discharge
±8kV
IEC 1000-4-2 Contact Discharge
♦
Single-Supply Operation
+2.7V to +3.6V (MAX1233)
+4.75V to +5.25V (MAX1234)
♦
4-Wire Touch-Screen Interface
♦
Internal +1.0V/+2.5V Reference or External
Reference (+1.0V to AV
DD
)
♦
SPI
™
/QSPI
™
/MICROWIRE
™
-Compatible 10MHz
Serial Interface
♦
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
♦
8-Bit DAC for LCD Bias Control
♦
4
×
4 Keypad Programmable Controller Offers Up
to Eight GPIO Pins
♦
Automatic Detection of Screen Touch, Key Press,
and End of Conversion
♦
Programmable 8-, 10-, 12-Bit Resolution
♦
Programmable Conversion Rates
♦
AutoShutdown
™
Between Conversions
♦
Low Power
260µA at 50ksps
50µA at 10ksps
6µA at 1ksps
0.3µA Shutdown Current
♦
28-Pin 5mm
×
5mm QFN and TQFN Packages
MAX1233/MAX1234
Applications
Personal Digital Assistants
Pagers
Touch-Screen Monitors
Cellular Phones
MP3 Players
Portable Instruments
Point-of-Sale Terminals
Pin Configuration
PENIRQ
SCLK
DOUT
BUSY
TOP VIEW
28
CS
KEYIRQ
Ordering Information
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 QFN (5mm x 5mm)
28 TQFN (5mm x 5mm)
28 QFN (5mm x 5mm)
28 TQFN (5mm x 5mm)
21
20
19
C4
C3
C2
C1
R1
R2
R3
27
26
DIN
25
24
23
DV
DD
AV
DD
*X+
*Y+
*X-
*Y-
GND
1
2
3
4
5
6
7
10
11
12
13
14
8
9
22
MAX1233EGI
MAX1233ETI
MAX1234EGI
MAX1234ETI
MAX1233
MAX1234
18
17
16
15
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.
1
DACOUT
*AUX1
QFN/TQFN
*PIN INCLUDES 8kV/15kV ESD PROTECTION.
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
*AUX2
*BAT1
*BAT2
REF
R4
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
MAX1233/MAX1234
ABSOLUTE MAXIMUM RATINGS
AV
DD
to GND............................................................-0.3V to +6V
DV
DD
to AV
DD
.......................................................-0.3V to +0.3V
Digital Inputs/Outputs to GND .................-0.3V to (DV
DD
+ 0.3V)
X+, Y+, X-, Y-, AUX1, AUX2,
and REF to GND ..................................-0.3V to (AV
DD
+ 0.3V)
BAT1, BAT2 to GND .................................................-0.3V to +6V
Maximum ESD per IEC 1000-4-2 (per MIL STD-883 HBM)
X+, X-, Y+, Y-, AUX1, AUX2, BAT1, BAT2......................±15kV
All Other Pins.....................................................................±2.5kV
Maximum Current into Any Pin............................................50mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin QFN (derate 28.5mW/°C above +70°C) .................2W
28-Pin TQFN (derate 28.5mW/°C above +70°C) ...............2W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(DV
DD
= AV
DD
= +2.7V to +3.6V (MAX1233), DV
DD
= AV
DD
= +4.75V to +5.25V (MAX1234), external reference V
REF
= 2.5V
(MAX1233), V
REF
= 4.096V (MAX1234); f
SCLK
= 10MHz, f
SAMPLE
= 50ksps, 12-bit mode, 0.1µF capacitor at REF, T
A
= -40°C to
+85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
(Note 1)
Resolution
No Missing Codes
Relative Accuracy (Note 2)
Differential Nonlinearity
Offset Error
INL
DNL
12-bit mode
10-bit and 8-bit modes
12-bit mode
10-bit and 8-bit modes
12-bit mode
10-bit and 8-bit modes
12-bit mode
Gain Error (Note 3)
10-bit mode
8-bit mode
Total Unadjusted Error
Offset Temperature Coefficient
Gain Temperature Coefficient
Channel-to-Channel Offset
Channel-to-Channel Gain
Matching
Noise
Including internal V
REF
Full-scale
input
MAX1233
AV
DD
= DV
DD
= +2.7V to +3.6V
MAX1234
AV
DD
= DV
DD
= +5V
±5%
TUE
12-bit mode
10-bit and 8-bit modes
Software-programmable 8/10/12 bit
11
±0.8
±0.5
±0.8
±0.5
±0.5
±0.5
±0.5
±0.5
±0.5
±2
±1
±0.4
±0.4
±0.1
±0.1
50
±0.4
mV
±0.3
LSB
ppm/°C
ppm/°C
LSB
LSB
µV
RMS
±4
LSB
±4
±2
±2
12
Bits
Bits
LSB
LSB
LSB
SYMBOL
CONDITIONS
ANALOG-TO-DIGITAL CONVERTER
MIN
TYP
MAX
UNITS
Power-Supply Rejection
PSR
DYNAMIC SPECIFICATIONS (1kHz SINE WAVE, V
IN
= 2.5V
P-P
FOR MAX1233, V
IN
= 4.096V
P-P
FOR MAX1234, 50ksps,
f
SCLK
= 10MHz)
Signal-to-Noise Plus Distortion
SINAD
69
dB
2
_______________________________________________________________________________________
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= +2.7V to +3.6V (MAX1233), DV
DD
= AV
DD
= +4.75V to +5.25V (MAX1234), external reference V
REF
= 2.5V
(MAX1233), V
REF
= 4.096V (MAX1234); f
SCLK
= 10MHz, f
SAMPLE
= 50ksps, 12-bit mode, 0.1µF capacitor at REF, T
A
= -40°C to
+85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Total Harmonic Distortion
Spurious-Free Dynamic Range
Full-Power Bandwidth
Full-Linear Bandwidth
CONVERSION RATE
Internal Oscillator Frequency
Aperture Delay
Aperture Jitter
Maximum Serial Clock Frequency
Duty Cycle
AUXILIARY ANALOG INPUTS (AUX1, AUX2)
Input Voltage Range
Input Leakage Current
Input Capacitance
BATTERY MONITOR INPUTS (BAT1, BAT2)
Input Voltage Range
Input Impedance
Accuracy
TEMPERATURE MEASUREMENT
Temperature Range
Resolution
Accuracy
INTERNAL ADC REFERENCE
Reference Output Voltage
Output Tempco
Reference Output Impedance
Reference Short-Circuit Current
EXTERNAL ADC REFERENCE (INTERNAL REFERENCE DISABLED, REFERENCE APPLIED TO REF)
Reference Input Voltage Range
Input Impedance
Input Current
(Note 6)
CS
= GND or V
DD
V
REF
= +2.5V at 50ksps (MAX1233)
V
REF
= +4.096V at 50ksps (MAX1234)
Shutdown/between conversions
1.0
1
5
8
±0.1
10
15
µA
V
DD
V
GΩ
V
REF
TCV
REF
Normal operation
2.5V mode, T
A
= +25°C
1.0V mode, T
A
= +25°C
2.470
0.980
2.500
1.000
60
250
18
2.530
1.020
ppm/°C
Ω
mA
V
Differential method (Note 4)
Single measurement method (Note 5)
Differential method (Note 4)
Single measurement method (Note 5)
-40
1.6
0.3
±3
±2
+85
°C
°C
°C
Sampling battery
Battery monitor OFF
Internal reference
-3
0.5
10
1
+3
6.0
V
kΩ
GΩ
%
Channel not selected or conversion
stopped
0
±0.1
34
V
REF
±1
V
µA
pF
f
SCLK
10
30
70
8
30
<50
11.5
MHz
ns
ps
MHz
%
SYMBOL
THD
SFDR
-3dB point
SINAD > 67dB
CONDITIONS
MIN
TYP
-84
84
0.5
50
MAX
UNITS
dB
dB
MHz
kHz
MAX1233/MAX1234
_______________________________________________________________________________________
3
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
MAX1233/MAX1234
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= +2.7V to +3.6V (MAX1233), DV
DD
= AV
DD
= +4.75V to +5.25V (MAX1234), external reference V
REF
= 2.5V
(MAX1233), V
REF
= 4.096V (MAX1234); f
SCLK
= 10MHz, f
SAMPLE
= 50ksps, 12-bit mode, 0.1µF capacitor at REF, T
A
= -40°C to
+85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DC ACCURACY
Resolution
Integral Linearity Error
Differential Linearity Error
Offset Error
Offset Error Temperature
Coefficient
Full-Scale Error
Full-Scale Error Temperature
Coefficient
DYNAMIC PERFORMANCE
Voltage Output Slew Rate
Output Settling Time
Glitch Impulse
Wake-Up Time
DAC OUTPUT
Internal DAC Reference
Output Load Regulation
Output Resistance
V
REFDAC
(Note 10)
Code = 255; 0 to 100µA
Code = 0; 0 to 100µA
Power-down mode
TOUCH-SCREEN CONTROLLER
On-Resistance
Touch-Detection Internal Pullup
Resistance
Pullup Resistance
Pulldown Resistance
DIGITAL INPUTS (SCLK,
CS,
DIN, R_, C_)
Input Voltage Low
Input Voltage High
Input Leakage Current
V
IL
V
IH
I
L
0.7
✕
DV
DD
±0.1
±1
0.3
✕
DV
DD
V
V
µA
Y+, X+
Y-, X-
X+ to AV
DD
KEYPAD CONTROLLER
C4, C3, C2, C1 (Note 11)
R4, R3, R2, R1 (Note 11)
DIGITAL INTERFACE
0.5
16
kΩ
kΩ
7
9
1
Ω
MΩ
0.85
✕
AV
DD
0.9
✕
AV
DD
0.5
0.5
1.0
0.95
✕
AV
DD
V
LSB
MΩ
Positive and negative
0.5LSB; 50kΩ and 50pF load (Note 9)
Code 127 to 128
From shutdown
0.4
20
40
50
V/µs
µs
nV/s
µs
Code = 255, no load
Code = 255, no load
±10
INL
DNL
V
OS
(Note 7)
No missing codes
(Note 8)
±1
1
5
SYMBOL
CONDITIONS
DIGITAL-TO-ANALOG CONVERTER
8
±1.0
±1.0
±25
Bits
LSB
LSB
mV
ppm/°C
%
ppm/°C
MIN
TYP
MAX
UNITS
4
_______________________________________________________________________________________
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
ELECTRICAL CHARACTERISTICS (continued)
(DV
DD
= AV
DD
= +2.7V to +3.6V (MAX1233), DV
DD
= AV
DD
= +4.75V to +5.25V (MAX1234), external reference V
REF
= 2.5V
(MAX1233), V
REF
= 4.096V (MAX1234); f
SCLK
= 10MHz, f
SAMPLE
= 50ksps, 12-bit mode, 0.1µF capacitor at REF, T
A
= -40°C to
+85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Input Capacitance
DIGITAL OUTPUT (DOUT)
Output Voltage Low
Output Voltage High
V
OL
V
OH
I
SINK
= 2mA
I
SINK
= 4mA
I
SOURCE
= 1.5mA
DV
DD
-
0.5
0.4
DV
DD
-
0.5
2.7
4.75
3
5
0.5
150
150
670
100
40
40
40
0
C
LOAD
= 50pF
C
LOAD
= 50pF
C
LOAD
= 50pF
40
0
C
LOAD
= 50pF (Note 13)
40
230
40
45
40
3.6
5.25
5
500
230
900
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
µA
0.4
0.8
V
V
SYMBOL
C
IN
CONDITIONS
MIN
TYP
15
MAX
UNITS
pF
MAX1233/MAX1234
DIGITAL OUTPUT (BUSY,
PENIRQ, KEYIRQ,
R_, C_)
Output Voltage Low
Output Voltage High
V
OL
V
OH
I
SINK
= 0.2mA
I
SOURCE
= 0.2mA
POWER REQUIREMENTS
Supply Voltage (Note 12)
AV
DD
/
DV
DD
I
AVDD
+
I
DVDD
MAX1233
MAX1234
Idle; all blocks shut down
Analog and Digital Supply
Current
TIMING CHARACTERISTICS
SCLK Clock Period
SCLK Pulse Width High
SCLK Pulse Width Low
DIN to SCLK Rise Setup
SCLK Rise to DIN Hold
SCLK Fall to DOUT Valid
CS
Fall to DOUT Enabled
CS
Rise to DOUT Disabled
CS
Fall to SCLK Rise
CS
Fall to SCLK Ignored
SCLK Rise to R_/C_ Data Valid
CS
Pulse Width High
t
CP
t
CH
t
CL
t
DS
t
DH
t
DOV
t
DV
t
DOD
t
CSS
t
CSH
t
GPO
t
CSW
Only ADC on; f
SAMPLE
= 20ksps
Only DAC on; no load
Only internal reference on
V
V
V
Note 1:
Tested at DV
DD
= AV
DD
= +2.7V (MAX1233), DV
DD
= AV
DD
= +5V (MAX1234).
Note 2:
Relative accuracy is the deviation of the analog value at any code from its theoretical value after the offset and gain errors
have been removed.
Note 3:
Offset nulled.
Note 4:
Difference between TEMP1 and TEMP2; temperature in °K = (V
TEMP2
- V
TEMP1
)
×
2680°K/V. No calibration is necessary.
Note 5:
Temperature coefficient is -2.1mV/°C. Determine absolute temperature by extrapolating from a calibrated value.
Note 6:
ADC performance is limited by the conversion noise floor, typically 300µV
P-P
. An external reference below 2.5V can
compromise the ADC performance.
Note 7:
Guaranteed from code 5 to 255.
_______________________________________________________________________________________
5
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