MXB7843_05 Datasheet, PDF (1/21 Pages) Maxim Integrated Products – 2.375V to 5.25V, 4-Wire Touch-Screen Controller

19-2435; Rev 1; 9/05
2.375V to 5.25V, 4-Wire Touch-Screen
Controller
General Description
The MXB7843 is an industry-standard 4-wire touch-
screen controller. It contains a 12-bit sampling analog-
to-digital converter (ADC) with a synchronous serial
interface and low on-resistance switches for driving
resistive touch screens. The MXB7843 uses an external
reference. The MXB7843 can make absolute or ratio-
metric measurements. The MXB7843 has two auxiliary
ADC inputs. All analog inputs are fully ESD protected,
eliminating the need for external TransZorb™ devices.
The MXB7843 is guaranteed to operate with a single
2.375V to 5.25V supply voltage. In shutdown mode, the
typical power consumption is reduced to under 0.5µW,
while the typical power consumption at 125ksps
throughput and a 2.7V supply is 650µW.
Low-power operation makes the MXB7843 ideal for bat-
tery-operated systems, such as personal digital assis-
tants with resistive touch screens and other portable
equipment. The MXB7843 is available in 16-pin QSOP
and TSSOP packages, and is guaranteed over the
-40°C to +85°C temperature range.
Applications
Personal Digital Assistants
Portable Instruments
Point-of-Sales Terminals
Pagers
Touch-Screen Monitors
Cellular Phones
Typical Application Circuit appears at end of data sheet.
TransZorb is a trademark of Vishay Intertechnology, Inc.
SPI/QSPI are trademarks of Motorola, Inc.
Features
♦ ESD-Protected ADC Inputs
±15kV IEC 61000-4-2 Air-Gap Discharge
±8kV IEC 61000-4-2 Contact Discharge
♦ Pin Compatible with MXB7846
♦ +2.375V to +5.25V Single Supply
♦ 4-Wire Touch-Screen Interface
♦ Ratiometric Conversion
♦ SPI™/QSPI™, 3-Wire Serial Interface
♦ Programmable 8-/12-Bit Resolution
♦ Two Auxiliary Analog Inputs
♦ Automatic Shutdown Between Conversions
♦ Low Power
270µA at 125ksps
115µA at 50ksps
25µA at 10ksps
5µA at 1ksps
2µA Shutdown Current
PART
MXB7843EEE
MXB7843EUE
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 QSOP
16 TSSOP
Pin Configuration
TOP VIEW
V_{DD 1}
X+ 2
Y+ 3
X- 4
Y- 5
GND 6
IN3 7
IN4 8
MXB7843
16 DCLK
15 CS
14 DIN
13 BUSY
12 DOUT
11 PENIRQ
10 V_DD
9 REF
QSOP/TSSOP
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