Features: 4-wire touch screen interface On-chip temperature sensor: −40°C to +85°C On-chip 2.5 V reference Direct battery measurement (0 V to 6 V) Touch-pressure measurement Specified throughput rate of 125 kSPS Single supply, VCC of 2.2 V to 5.25 V Ratiometric conversion High speed serial interface Programmable 8-bit or 12-bit resolution One auxiliary analog input Shutdown mode: 1 A max 16-lead QSOP, TSSOP,and LFCSP packages
Pinout
Specifications
| Parameter |
Rating |
| +VCC to GND |
0.3 V to +7 V |
| Analog Input Voltage to GND |
0.3 V to VCC + 0.3 V |
| Digital Input Voltage to GND |
0.3 V to VCC + 0.3 V |
| Digital Output Voltage to GND |
0.3 V to VCC + 0.3 V |
| VREF to GND |
0.3 V to VCC + 0.3 V |
| Input Current to Any Pin Except Supplies1 |
±10 mA |
| Operating Temperature Range |
|
| Commercial (A, B Versions) |
40to +85 |
| Storage Temperature Range |
65to +150 |
| Junction Temperature |
150 |
| QSOP, TSSOP, LFCSP Packages, Power Dissipation |
450 mW |
| JA Thermal Impedance |
149.97/W (QSOP)
150.4/W (TSSOP)
135.7/W (LFCSP) |
| JC Thermal Impedance |
38.8/W (QSOP)
27.6/W(TSSOP) |
| IR Reflow Soldering |
|
| Peak Temperature |
220 (±5) |
| Time-to-Peak Temperature |
10 sec to 30 sec |
| Ramp-Down Rate |
6/sec max |
| Pb-free Parts Only: |
|
| Peak Temperture |
250 |
| Time-to-Peak Temperature |
20 sec to 40 sec |
| Ramp-Up Rate |
3/sec max |
| Ramp-Down Rate |
6/sec max |
| Resolution (Bits) |
12bit |
| T-Put Rate |
125kSPS |
| # Chan |
6 |
| Supply V |
Single(+3),Single(+3.3) |
| Pwr Diss (max) |
1.4mW |
| Interface |
Ser |
| Ain Range |
Uni (Vref),Uni 2.5V |
| Pkg Type |
CSP,SOP |
Description
The AD7873 is a 12-bit successive approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The AD7873 operates from a single 2.2 V to 5.25 V power supply and features throughput rates greater than 125 kSPS.
The AD7873 features direct battery measurement, temperature measurement, and touch-pressure measurement. The AD7873 also has an on-board reference of 2.5 V that can be used for the auxiliary input, battery monitor, and temperature measurement modes. When not in use, the internal reference can be shut down to conserve power. An external reference can also be applied and can be varied from 1 V to VCC, while the analog input range is from 0 V to VREF. The device includes a shutdown mode that reduces the current consumption to less than 1 A.
The AD7873 features on-board switches. This, coupled with low power and high speed operation, makes the device ideal for battery-powered systems such as personal digital assistants with resistive touch screens and other portable equipment. The part is available in a 16-lead 0.15" quarter size outline package (QSOP), a 16-lead thin shrink small outline package (TSSOP), and a 16-lead lead frame chip scale package (LFCSP).
AD7873 Data Sheet
