General Description
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
TM
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.
Applications
Personal Digital Assistants
Pagers
Touch-Screen Monitors
Cellular Phones
MP3 Players
Portable Instruments
Point-of-Sale Terminals
Features
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
TM
/QSPI
TM
/MICROWIRE
TM
-Compatible 10MHz
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
o Automatic Detection of Screen Touch, Key Press,
and End of Conversion
o Programmable 8-, 10-, 12-Bit Resolution
o Programmable Conversion Rates
o AutoShutdown
TM
Between Conversions
o Low Power
260µA at 50ksps
50µA at 10ksps
6µA at 1ksps
0.3µA Shutdown Current
o 28-Pin 5mm × 5mm QFN Package
MAX1233/MAX1234
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
________________________________________________________________ Maxim Integrated Products
1
28
27
26
25
24
23
22
SCLK
CS
DIN
DOUT
PENIRQ
8
9
10
11
12
13
14
*BAT1
*BAT2
*AUX1
*AUX2
REF
DACOUT
R4
15
16
17
18
19
20
21
R3
*PIN INCLUDES 8kV/15kV ESD PROTECTION.
R2
R1
C1
C2
C3
C4
7
6
5
4
3
2
1
GND
*Y-
*X-
*Y+
*X+
AV
DD
DV
DD
MAX1233
MAX1234
QFN
TOP VIEW
KEYIRQ
BUSY
Pin Configuration
Ordering Information
19-2512; Rev 0; 7/02
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.
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
PIN-PACKAGE
MAX1233EGI
-40°C to +85°C
28 QFN (5mm
× 5mm)
MAX1234EGI
-40°C to +85°C
28 QFN (5mm
× 5mm)
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.
MAX1233/MAX1234
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.)
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.
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
Operating Temperature Range ...........................-40
°C to +85°C
Storage Temperature Range .............................-60
°C to +150°C
Lead Temperature (soldering, 10s) .................................+300
°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ANALOG-TO-DIGITAL CONVERTER
DC ACCURACY (Note 1)
Resolution
Software-programmable 8/10/12 bit
12
Bits
No Missing Codes
11
Bits
12-bit mode
±0.8
±2
Relative Accuracy (Note 2)
INL
10-bit and 8-bit modes
±0.5
LSB
12-bit mode
±0.8
±2
Differential Nonlinearity
DNL
10-bit and 8-bit modes
±0.5
LSB
12-bit mode
±0.5
±4
Offset Error
10-bit and 8-bit modes
±0.5
LSB
12-bit mode
±0.5
±4
10-bit mode
±0.5
Gain Error (Note 3)
8-bit mode
±0.5
LSB
12-bit mode
±2
Total Unadjusted Error
TUE
10-bit and 8-bit modes
±1
LSB
Offset Temperature Coefficient
±0.4
ppm/
°C
Gain Temperature Coefficient
±0.4
ppm/
°C
Channel-to-Channel Offset
±0.1
LSB
Channel-to-Channel Gain
Matching
±0.1
LSB
Noise
Including internal V
REF
50
µV
RMS
MAX1233
AV
DD
= DV
DD
= +2.7V to +3.6V
±0.4
Power-Supply Rejection
PSR
Full-scale
input
MAX1234
AV
DD
= DV
DD
= +5V
±5%
±0.3
mV
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
MAX1233/MAX1234
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
_______________________________________________________________________________________
3
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
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Total Harmonic Distortion
THD
-84
dB
Spurious-Free Dynamic Range
SFDR
84
dB
Full-Power Bandwidth
-3dB point
0.5
MHz
Full-Linear Bandwidth
SINAD > 67dB
50
kHz
CONVERSION RATE
Internal Oscillator Frequency
8
11.5
MHz
Aperture Delay
30
ns
Aperture Jitter
<50
ps
Maximum Serial Clock Frequency
f
SCLK
10
MHz
Duty Cycle
30
70
%
AUXILIARY ANALOG INPUTS (AUX1, AUX2)
Input Voltage Range
0
V
REF
V
Input Leakage Current
Channel not selected or conversion
stopped
±0.1
±1
µA
Input Capacitance
34
pF
BATTERY MONITOR INPUTS (BAT1, BAT2)
Input Voltage Range
0.5
6.0
V
Sampling battery
10
k
Input Impedance
Battery monitor OFF
1
G
Accuracy
Internal reference
-3
+3
%
TEMPERATURE MEASUREMENT
Temperature Range
-40
+85
°C
Differential method (Note 4)
1.6
Resolution
Single measurement method (Note 5)
0.3
°C
Differential method (Note 4)
±3
Accuracy
Single measurement method (Note 5)
±2
°C
INTERNAL ADC REFERENCE
2.5V mode, T
A
= +25
°C
2.470
2.500
2.530
Reference Output Voltage
V
REF
1.0V mode, T
A
= +25
°C
0.980
1.000
1.020
V
Output Tempco
TCV
REF
60
ppm/
°C
Reference Output Impedance
Normal operation
250
Reference Short-Circuit Current
18
mA
EXTERNAL ADC REFERENCE (INTERNAL REFERENCE DISABLED, REFERENCE APPLIED TO REF)
Reference Input Voltage Range
(Note 6)
1.0
V
DD
V
Input Impedance
CS = GND or V
DD
1
G
V
REF
= +2.5V at 50ksps (MAX1233)
5
10
V
REF
= +4.096V at 50ksps (MAX1234)
8
15
Input Current
Shutdown/between conversions
±0.1
µA
MAX1233/MAX1234
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
4
_______________________________________________________________________________________
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
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL-TO-ANALOG CONVERTER
DC ACCURACY
Resolution
8
Bits
Integral Linearity Error
INL
(Note 7)
±1.0
LSB
Differential Linearity Error
DNL
No missing codes
±1.0
LSB
Offset Error
V
OS
(Note 8)
±1
±25
mV
Offset Error Temperature
Coefficient
1
ppm/
°C
Full-Scale Error
Code = 255, no load
5
%
Full-Scale Error Temperature
Coefficient
Code = 255, no load
±10
ppm/
°C
DYNAMIC PERFORMANCE
Voltage Output Slew Rate
Positive and negative
0.4
V/µs
Output Settling Time
0.5LSB; 50k
and 50pF load (Note 9)
20
µs
Glitch Impulse
Code 127 to 128
40
nV/s
Wake-Up Time
From shutdown
50
µs
DAC OUTPUT
Internal DAC Reference
V
REFDAC
(Note 10)
0.85
AV
DD
0.9
AV
DD
0.95
AV
DD
V
Code = 255; 0 to 100µA
0.5
Output Load Regulation
Code = 0; 0 to 100µA
0.5
LSB
Output Resistance
Power-down mode
1.0
M
TOUCH-SCREEN CONTROLLER
Y+, X+
7
On-Resistance
Y-, X-
9
Touch-Detection Internal Pullup
Resistance
X+ to AV
DD
1
M
KEYPAD CONTROLLER
Pullup Resistance
C4, C3, C2, C1 (Note 11)
0.5
k
Pulldown Resistance
R4, R3, R2, R1 (Note 11)
16
k
DIGITAL INTERFACE
DIGITAL INPUTS (SCLK, CS, DIN, R_, C_)
Input Voltage Low
V
IL
0.3
DV
DD
V
Input Voltage High
V
IH
0.7
DV
DD
V
Input Leakage Current
I
L
±0.1
±1
µA
MAX1233/MAX1234
±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
_______________________________________________________________________________________
5
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
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input Capacitance
C
IN
15
pF
DIGITAL OUTPUT (DOUT)
I
SINK
= 2mA
0.4
Output Voltage Low
V
OL
I
SINK
= 4mA
0.8
V
Output Voltage High
V
OH
I
SOURCE
= 1.5mA
DV
DD
-
0.5
V
DIGITAL OUTPUT (BUSY, PENIRQ, KEYIRQ, R_, C_)
Output Voltage Low
V
OL
I
SINK
= 0.2mA
0.4
V
Output Voltage High
V
OH
I
SOURCE
= 0.2mA
DV
DD
-
0.5
V
POWER REQUIREMENTS
MAX1233
2.7
3
3.6
Supply Voltage (Note 12)
AV
DD
/
DV
DD
MAX1234
4.75
5
5.25
V
Idle; all blocks shut down
0.5
5
Only ADC on; f
SAMPLE
= 20ksps
150
500
Only DAC on; no load
150
230
Analog and Digital Supply
Current
I
AVDD
+
I
DVDD
Only internal reference on
670
900
µA
TIMING CHARACTERISTICS
SCLK Clock Period
t
CP
100
ns
SCLK Pulse Width High
t
CH
40
ns
SCLK Pulse Width Low
t
CL
40
ns
DIN to SCLK Rise Setup
t
DS
40
ns
SCLK Rise to DIN Hold
t
DH
0
ns
SCLK Fall to DOUT Valid
t
DOV
C
LOAD
= 50pF
40
ns
CS Fall to DOUT Enabled
t
DV
C
LOAD
= 50pF
45
ns
CS Rise to DOUT Disabled
t
DOD
C
LOAD
= 50pF
40
ns
CS Fall to SCLK Rise
t
CSS
40
ns
CS Fall to SCLK Ignored
t
CSH
0
ns
SCLK Rise to R_/C_ Data Valid
t
GPO
C
LOAD
= 50pF (Note 13)
230
ns
CS Pulse Width High
t
CSW
40
ns
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.
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