MXB7846EEE+T Maxim Integrated Products, MXB7846EEE+T Datasheet - Page 16

• Manufacturer Part Number: MXB7846EEE+T
• Description: IC CNTRLR TOUCH RES 16QSOP
• Manufacturer: Maxim Integrated Products
• Type: Temperature Sensorr

Specifications of MXB7846EEE+T

• Input Type: Analog
• Output Type: Digital
• Interface: 4-Wire
• Current - Supply: 950µA
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 9. Conversion Timing, 24-Clock per Conversion, 8-Bit Bus Interface
The fastest the MXB7846 can run with CS held continu-
ously low is 15 clock conversions. Figure 10 shows the
serial-interface timing necessary to perform a conver-
sion every 15 DCLK cycles. If CS is connected low and
DCLK is continuous, guarantee a start bit by first clock-
ing in 16 zeros.
Most microcontrollers (µCs) require that data transfers
occur in multiples of eight DCLK cycles; 16 clocks per
conversion is typically the fastest that a µC can drive the
MXB7846. Figure 11 shows the serial interface timing nec-
essary to perform a conversion every 16 DCLK cycles.
2.375V to 5.25V, 4-Wire Touch-Screen Controller
with Internal Reference and Temperature Sensor
Table 4. Power-Mode Selection
16
PD1
0
0
1
1
______________________________________________________________________________________
DCLK
CS
DIN
BUSY
DOUT
PD0
A/D STATE
0
1
0
1
DRIVERS 1 AND 2
(SER/DFR HIGH)
DRIVERS 1 AND 2
(SER/DFR LOW)
(START)
S
1
Disabled
Disabled
Disabled
PENIRQ
Enabled
A2
IDLE
A1
IDLE
A0 MODE
4
RB1
OFF
OFF
T
ADC is ON during conversion, OFF between conversion
ADC is always ON, reference is always OFF
ADC is always OFF, reference is always ON
ADC is always ON, reference is always ON
B
SER/
DFR
ACQUIRE
ACQUIRE
PD1
t
ACQ
PD0
8
ON
9
(MSB)
11
STATUS
10
9
12
OFF
R
ON
B2
8
The MXB7846 provides an 8-bit conversion mode
selected by setting the MODE bit in the control byte
high. In the 8-bit mode, conversions complete four
clock cycles earlier than in the 12-bit output mode,
resulting in 25% faster throughput. This can be used in
conjunction with serial interfaces that provide 12-bit
transfers, or two conversions could be accomplished
with three 8-bit transfers. Not only does this shorten each
conversion by 4 bits, but each conversion can also
occur at a faster clock rate since settling to better than 8
bits is all that is required. The clock rate can be as much
as 25% faster. The faster clock rate and fewer clock
cycles combine to increase the conversion rate.
CONVERSION
7
6
CONVERSION
5
16
4
3
2
1
CONVERSION
20
(LSB)
0
SUPPLY CURRENT (typ) (µA)
R
DURING
B3
200
200
400
600
IDLE
IDLE
8-Bit Conversion
OFF
24
CONVERSION
AFTER
200
400
600
1