LH79524 Datasheet, PDF (27/64 Pages) NXP Semiconductors – System-on-Chip

System-on-Chip
NXP Semiconductors
LH79524/LH79525
ADC and Brownout Detector
The ADC block consists of an 10-channel, 10-bit
Analog-to-Digital Converter with integrated Touch
Screen Controller (TSC). The complete touch screen
interface is achieved by combining the front-end bias-
ing, control circuitry with analog-to-digital conversion,
reference generation, and digital control.
The ADC has a bias-and-control network that allows
correct operation with both 4- and 5-wire touch panels.
A 16-entry × 16-bit wide FIFO holds a 10-bit ADC
output and a 4-bit tag number.
When the screen is touched, it pushes the conduc-
tive coating on the coversheet against the coating
on the glass, making electrical contact. The voltages
produced are the analog representation of the position
touched. The voltage level of the coversheet is
converted continuously by the ADC and monitored by
the system.
Other features include:
• 10-bit fully differential Successive Approximation
Register (SAR) with integrated sample/hold
• A 10-channel multiplexer that routes user-selected
inputs to the ADC in single-ended and differential
modes
• A 16-entry × 16-bit wide FIFO that holds the 10-bit
ADC output
• Front bias-and-control network for touch screen
interface and support functions, which are compati-
ble with industry-standard 4- and 5-wire touch-sensi-
tive panels
• Touch-pressure sensing circuits
• Pen-down sensing circuit and interrupt generator
• Independent voltage reference generator
• Conversion automation function to minimize
interrupt overhead
• Brownout Detector
• Battery Control Signal.
ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings
PARAMETER
DC Core Supply Voltage
DC I/O Supply Voltage
DC Analog Supply
Voltage for ADC
Storage Temperature
SYMBOL RATING UNIT
VDDC -0.3 to 2.4 V
VDD -0.3 to 4.6 V
VDDA0 -0.3 to 4.6 V
VDDA1 -0.3 to 2.4 V
VDDA2 -0.3 to 2.4 V
TSTG -55 to +125 °C
NOTE: These stress ratings are only for transient conditions. Oper-
ation at or beyond absolute maximum rating conditions may
affect reliability and cause permanent damage to the device.
Recommended Operating Conditions
PARAMETER
MINIMUM TYPICAL
DC Core Supply Voltage (VDDC)
DC I/O Supply Voltage (VDD)
DC Analog Supply Voltage (VDDA0)
DC Analog Supply Voltage (VDDA1)
DC Analog Supply Voltage (VDDA2)
Clock Frequency
Crystal Frequency
Operating Temperature (Industrial)
1.7 V
3.0 V
3.0 V
1.7 V
1.7 V
3.27 MHz
10.0 MHz
-40°C
1.8 V
3.3 V
3.3 V
1.8 V
1.8 V
11.2896 MHz
25°C
MAXIMUM
1.9 V
3.6 V
3.6 V
1.9 V
1.9 V
76.205 MHz
20.0 MHz
+85°C
NOTES
1, 4
4
2
3
NOTES:
1. Linear Regulator disabled.
2. With PLL enabled. Without PLL, minimum frequency is 0 MHz.
Some peripherals may not operate at minimum frequency.
3. Choose 11.2896 MHz to ensure proper operation of the I²S, USB,
and UART peripherals.
4. Core Voltage should never exceed I/O Voltage after initial power
up. See “Power Supply Sequencing” on page 28.
Preliminary data sheet
Rev. 01 — 16 July 2007
27