MXB7846EEE+T Maxim Integrated Products, MXB7846EEE+T Datasheet

IC CNTRLR TOUCH RES 16QSOP

MXB7846EEE+T

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

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
The MXB7846 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 MXB7846 uses an internal
+2.5V reference or an external reference. The
MXB7846 can make absolute or ratiometric measure-
ments. In addition, this device has an on-chip tempera-
ture sensor, a battery-monitoring channel, and has the
ability to perform touch-pressure measurements without
external components. The MXB7846 has one auxiliary
ADC input. All analog inputs are fully ESD protected,
eliminating the need for external TransZorb™ devices.
The MXB7846 is guaranteed to operate with a supply
voltage down to +2.375V when used with an external
reference or +2.7V with an internal reference. In shut-
down 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 MXB7846 ideal for bat-
tery-operated systems, such as personal digital assis-
tants with resistive touch screens and other portable
equipment. The MXB7846 is available in 16-pin QSOP
and TSSOP packages, and is guaranteed over the
-40°C to +85°C temperature range.
Typical Application Circuit appears at end of data sheet.
19-2436; Rev 2; 1/08
with Internal Reference and Temperature Sensor
TRANSZORB is a trademark of Vishay Intertechnology, Inc.
SPI/QSPI are trademarks of Motorola, Inc.
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.
2.375V to 5.25V, 4-Wire Touch-Screen Controller
Personal Digital Assistants
Portable Instruments
Point-of-Sales Terminals
Pagers
Touch-Screen Monitors
Cellular Phones
________________________________________________________________ Maxim Integrated Products
General Description
Applications
♦ ESD-Protected ADC Inputs
♦ Pin Compatible with MXB7843
♦ +2.375V to +5.25V Single Supply
♦ Internal +2.5V Reference
♦ Direct Battery Measurement (0 to 6V)
♦ On-Chip Temperature Measurement
♦ Touch-Pressure Measurement
♦ 4-Wire Touch-Screen Interface
♦ Ratiometric Conversion
♦ SPI™/QSPI™, 3-Wire Serial Interface
♦ Programmable 8-/12-Bit Resolution
♦ Auxiliary Analog Input
♦ Automatic Shutdown Between Conversions
♦ Low Power (External Reference)
MXB7846EUE
MXB7846EEE
PART
±15kV IEC 61000-4-2 Air-Gap Discharge
±8kV IEC 61000-4-2 Contact Discharge
270µA at 125ksps
115µA at 50ksps
25µA at 10ksps
5µA at 1ksps
2µA Shutdown Current
TOP VIEW
GND
AUX
V
BAT
-40°C to +85°C
-40°C to +85°C
TEMP RANGE
DD
X+
Y+
X-
Y-
1
2
6
3
4
5
7
8
Ordering Information
QSOP/TSSOP
MXB7846
Pin Configuration
PIN-
PACKAGE
16 QSOP
16 TSSOP
16
15
14
13
12
11
10
9
DCLK
CS
DIN
BUSY
DOUT
PENIRQ
V
REF
DD
Features
CODE
U16-1
E16-6
PKG
1

Related parts for MXB7846EEE+T

MXB7846EEE+T Summary of contents

Page 1

... Typical Application Circuit appears at end of data sheet. TRANSZORB is a trademark of Vishay Intertechnology, Inc. SPI/QSPI are trademarks of Motorola, Inc. ________________________________________________________________ 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. ♦ ESD-Protected ADC Inputs ± ...

Page 2

Touch-Screen Controller with Internal Reference and Temperature Sensor ABSOLUTE MAXIMUM RATINGS , VBAT, DIN, CS, DCLK to GND ........................-0. Digital Outputs to GND...............................-0. X+, X-, Y+, Y-, AUX ...

Page 3

Touch-Screen Controller with Internal Reference and Temperature Sensor ELECTRICAL CHARACTERISTICS (continued 2.7V to 3.6V 2.5V REF DCLK unless otherwise noted. Typical values are at T MIN ...

Page 4

Touch-Screen Controller with Internal Reference and Temperature Sensor TIMING CHARACTERISTICS (Figure 2.7V to 3.6V 2.5V REF DCLK unless otherwise noted. Typical values are at T ...

Page 5

Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) INTEGRAL NONLINEARITY vs. DIGITAL OUTPUT CODE 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2 ...

Page 6

Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) INTERNAL REFERENCE VOLTAGE vs. TEMPERATURE 2.6 2.5 2.4 2.3 2.2 2 2.7V ...

Page 7

Touch-Screen Controller with Internal Reference and Temperature Sensor (V = 2.7V 2. REF EXTERNAL DCLK otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 250 f = 12.5kHz SAMPLE 225 200 175 150 ...

Page 8

Touch-Screen Controller with Internal Reference and Temperature Sensor PIN NAME 1 V Positive Supply Voltage. Connect to pin 10 Position Input, ADC Input Channel Position Input, ADC Input ...

Page 9

Touch-Screen Controller with Internal Reference and Temperature Sensor Detailed Description The MXB7846 uses a successive-approximation conver- sion technique to convert analog signals to a 12-bit digi- tal output. An SPI/QSPI/MICROWIRE™-compatible serial interface provides easy communication to ...

Page 10

Touch-Screen Controller with Internal Reference and Temperature Sensor BAT AUX REF Table 1. Input Configuration, Single-Ended Reference Mode (SER/DFR HIGH MEASUREMENT ...

Page 11

Touch-Screen Controller with Internal Reference and Temperature Sensor Input Bandwidth and Anti-Aliasing The ADCs input tracking circuitry has a 25MHz small- signal bandwidth possible to digitize high- speed transient events. To avoid high-frequency ...

Page 12

Touch-Screen Controller with Internal Reference and Temperature Sensor GND Figure 3. Single-Ended Y-Coordinate Measurement TOUCH SCREEN Figure 5. PENIRQ Functional Block Diagram 12 ______________________________________________________________________________________ REF +IN REF+ 12-BIT ADC -IN REF- ...

Page 13

Touch-Screen Controller with Internal Reference and Temperature Sensor SCREEN TOUCHED HERE PENIRQ CS DCLK DIN INTERRUPT PROCESSOR NO RESPONSE TO TOUCH⎯MASK PENIRQ t TOUCH Figure 6. PENIRQ Timing Diagram ...

Page 14

Touch-Screen Controller with Internal Reference and Temperature Sensor the ambient temperature. First, the PENIRQ diode for- ward bias voltage is measured by the ADC with an address and A0 ...

Page 15

Touch-Screen Controller with Internal Reference and Temperature Sensor Table 3. Control Byte Format BIT 7 BIT 6 BIT 5 START A2 A1 BIT NAME 7 START Start bit Address (Tables 1 and ...

Page 16

Touch-Screen Controller with Internal Reference and Temperature Sensor Table 4. Power-Mode Selection PENIRQ PD1 PD0 0 0 Enabled ADC is ON during conversion, OFF between conversion 0 1 Disabled ADC is always ON, reference is always ...

Page 17

Touch-Screen Controller with Internal Reference and Temperature Sensor The MXB7846 output data is in straight binary format as shown in Figure 12. This figure shows the ideal output code for the given input voltage and does ...

Page 18

Touch-Screen Controller with Internal Reference and Temperature Sensor byte (see Tables 3 and 4). Once the processor instructs the MXB7846 to initiate a conversion, the MXB7846 biases the touch screen through the internal switches at the ...

Page 19

Touch-Screen Controller with Internal Reference and Temperature Sensor Hardware Power-Down CS also places the MXB7846 into power-down. When CS goes HIGH, the MXB7846 immediately powers down and aborts the current conversion. The internal reference does not ...

Page 20

Touch-Screen Controller with Internal Reference and Temperature Sensor CS DCLK DIN START BUSY DOUT Figure 16. MXB7846-to-TMS320 Serial Interface Timing Diagram 2) The MXB7846’s CS pin is driven low by the TMS320’s XF ...

Page 21

Touch-Screen Controller with Internal Reference and Temperature Sensor Differential Nonlinearity Differential nonlinearity (DNL) is the difference between an actual step width and the ideal value of 1LSB. A DNL error specification of less than 1LSB guarantees ...

Page 22

Touch-Screen Controller with Internal Reference and Temperature Sensor (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 22 ______________________________________________________________________________________ Package Information ...

Page 23

Touch-Screen Controller with Internal Reference and Temperature Sensor (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) ______________________________________________________________________________________ Package Information (continued) PACKAGE ...

Page 24

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 24 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products ...

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