MAX1234ETI+T Maxim Integrated Products, MAX1234ETI+T Datasheet - Page 41

• Manufacturer Part Number: MAX1234ETI+T
• Description: IC CNTRLR TOUCH 28-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Resistiver

Specifications of MAX1234ETI+T

• Touch Panel Interface: 4-Wire
• Number Of Inputs/keys: 1, 4 x 4 Keypad
• Resolution (bits): 8, 10, 12 b
• Data Interface: MICROWIRE™, QSPI™, Serial, SPI™
• Data Rate/sampling Rate (sps, Bps): 50k
• Voltage Reference: Internal
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Applications: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Equation 5 shows that the maximum output voltage occurs
for the minimum DAC voltage, and that the minimum
output voltage occurs for the maximum DAC voltage.
To ensure that the desired output swing is achieved,
choose appropriate values of R1, R2, and R3.
Calculate V
If V
LCD/TFT display, the DAC codes that cause the output
voltage to go too high must be avoided.
Figure 27. LCD Contrast Control Circuit
Figure 28a. SPI Interface
Controllers Include DAC and Keypad Controller
V
OUTMAX
DD
V
+ (R1
OUTMAX
SS
MAX
OUTMAX
exceeds the maximum ratings of the
= V
/ R3
MAX1233
MAX1234
AV
SPI
DD
REFMAX
______________________________________________________________________________________
MIN
DAC
using the following equation:
) (V
MISO
MOSI
SCK
CS
REFMAX
+ (R1
DACOUT
±15kV ESD-Protected Touch-Screen
MAX
R3
i
3
RESISTORS
- V
FEEDBACK
CS
SCLK
DOUT
DIN
BUSY
PENIRQ
KEYIRQ
/ R2
DACMIN
R1
R2
[Equation 6]
MIN
MAX1233
MAX1234
i
i
1
2
)V
)
REFMAX
1.25V
V
ERROR AMP
REF
MAX1677
SIMPLIFIED DC/DC CONVERTER
Calculate V
If V
codes, which cause the output voltage to go too low.
When using an SPI interface (Figure 28a) or
MICROWIRE (Figure 28b), set the CPOL = CPHA = 0.
At least four 8-bit operations are necessary to read or
write data to/from the MAX1233/MAX1234. DOUT data
transitions on the serial clock’s falling edge and is
clocked into the µP on the SCLK’s rising edge. The first
Figure 28b. MICROWIRE Interface
OUTMIN
V
(R1
OUTMIN
CONTROL
MAX
MICROWIRE
is too low for desired operation, avoid the DAC
V
OUTMIN
BATT
Connection to Standard Interface
/ R3
= V
MIN
REFMIN
MISO
MOSI
SCK
using the following equation:
) (V
CS
SPI and MICROWIRE Interfaces
REFMIN
+ (R1
MIN
- V
CS
SCLK
DOUT
DIN
BUSY
PENIRQ
KEYIRQ
DACMAX
/ R2
(LCD BIAS)
MAX
MAX1233
MAX1234
V
[Equation 7]
OUT
)V
)
REFMIN
+
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