ADS7846E - 12-Bit 4-Wire Resistive Touch Screen Controller | TI
MPN: ADS7846E ✓ Hoạt độngADS7846E Tóm tắt
A touch screen controller is the interface IC that converts the resistive voltages produced by a four-wire glass or film panel into digital X and Y coordinates. Within the component hierarchy it sits as a touch screen controller within the family of data-converter ICs, whose core building block is a SAR ADC, and it ultimately belongs to the broader class of integrated circuits. Because the panel electrodes themselves form a variable resistive divider, the controller must both excite the panel and convert the resulting differential voltage accurately.
Key features of the ADS7846E include the 12-bit ADC resolution, 125 kHz sampling capability, a direct battery measurement channel that lets a portable product sense its own supply voltage, an on-chip temperature sensor for panel and system compensation, and a programmable internal reference that removes the need for an external precision reference. According to Texas Instruments, the device is 100% pin-compatible with the industry-standard ADS7843 and drops into the same socket, so existing ADS7843 designs can be upgraded with software changes only.
Internally the SAR core performs successive approximation on the differential voltage developed across the X+ and X− (or Y+ and Y−) electrodes. Differential sampling suppresses supply noise and panel-independent offsets, while the multiplexed AUX input extends the same converter to battery and temperature measurements. The digital side is a simple serial peripheral interface with chip select, data in, data out and clock, which keeps the pin count low and the host firmware straightforward.
Typical applications include industrial human-machine interfaces, point-of-sale terminals, portable test and measurement instruments, medical infusion pumps, and battery-operated panel equipment where direct battery measurement and on-chip temperature sensing simplify system design.
When designing around this controller, use the panel tail or PCB traces with a proper ground guard, keep the X/Y and AUX traces away from switching nodes and display backlight converters, and allow the internal reference and acquisition timing to settle before sampling. Pen-detection and interrupt handling should be configured so the host reads a settled conversion rather than polling blindly.
This page combines manufacturer specifications, a drop-in comparison against the closest same-package alternatives, and practical layout and design guidance that goes beyond the electrical tables in the original datasheet.
Bộ thay thế dễ dàng lắp đặt cho ADS7846E — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với ADS7846E (cùng hình factor và footprint) — khác nhau ở Operating Temperature Range, Package.
ADS7843E
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →TSC2046E
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
ADS7842EB
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →ADS7846E Tỷ lệ tối đa & tính chất điện
| Controller Type | 4-wire resistive touch screen controller |
| ADC Resolution | 12 bit |
| ADC Architecture | Successive-approximation (SAR) |
| Digital Interface | SPI, 4-wire (CS, DIN, DOUT, DCLK) |
| Supply Voltage Range | 2.7 V to 5.25 V |
| Conversion Throughput | 125 kHz |
| Khoảng nhiệt độ hoạt động | -40 C to +85 C |
| Hộp | SSOP-16 |
| Số chân | 16 pins |
| Kiểu lắp đặt | Surface mount |
| Backwards Compatibility | 100% pin-compatible with ADS7843, same socket |
| Direct Battery Measurement | Yes, via auxiliary (AUX) channel |
| On-Chip Temperature Sensor | Yes |
| Internal Reference | Programmable on-chip reference |
| RoHS Compliance | unknown |
Hướng dẫn cấu hình chân ADS7846E ssop-16
Cấu hình chân cho ADS7846E (ssop-16 gói). Thành phần số hiệu này có chân đầu vào, đầu ra và nguồn cung cấp. Tham khảo tài liệu thông số kỹ thuật của nhà sản xuất để biết cấu hình chân bù, bù trừ và chân kích hoạt. Hoàn hảo cho điều kiện tín hiệu và mạch khuếch đại.
Không có dữ liệu chân cụ thể sẵn có cho ADS7846E.
Tham khảo: tài liệu kỹ thuật cho cấu hình chân đầy đủ.
Ứng dụng tiêu biểu
ADS7846E phù hợp cho 6 Áp dụngs: Industrial Human-Machine Interfaces, Point-of-Sale and Retail Terminals, Portable Test and Measurement Instruments, Medical Infusion Pumps and Patient Monitors, Battery-Powered Panel Equipment, Educational and Kitchen Appliance Touch Panels.
Industrial Human-Machine Interfaces
The ADS7846E fits factory-floor operator panels where a 4-wire resistive screen must report precise touch coordinates over a long product life. Its 12-bit SAR conversion resolves the small differential voltages produced by typical glass panels, while the 125 kHz throughput gives the host enough samples to implement debounce, edge detection and simple gesture logic without the host controller polling overhead. Because the device runs from a 2.7 V to 5.25 V supply, it can sit directly on a 24 V industrial bus panel behind a regulated 5 V rail, and the -40 °C to +85 °C rating covers the temperature extremes of machine-side cabinets. The on-chip temperature sensor also gives the firmware a way to compensate the panel as it ages and cools.
Được đề xuất
Point-of-Sale and Retail Terminals
Point-of-sale terminals benefit from the ADS7846E because the controller handles the entire resistive touch front end in one 16-pin SSOP, leaving the host MCU free for display, keypad and payment peripheral handling. The SPI interface is simple enough for a low-cost microcontroller, and the 125 kHz throughput means a signature capture routine can sample the panel quickly enough to reconstruct handwriting strokes. Direct battery measurement is less central here, but the programmable internal reference removes an external precision reference component, reducing board area and bill of materials cost in volume consumer-retail builds.
Được đề xuất
Portable Test and Measurement Instruments
Handheld analyzers, meters and calibrators commonly use a 4-wire resistive display, and the ADS7846E gives them a compact, low-power touch front end. The 12-bit resolution is well matched to the pixel density of small instrument screens, and the direct battery measurement channel lets the firmware display a true pack voltage rather than an estimate derived from the regulated rail. The on-chip temperature sensor supports internal self-calibration tracking, which matters in portable equipment that is carried between ambient conditions. With a 2.7 V lower supply limit, the controller also fits designs powered from a single-cell Li-ion with a low-dropout front end.
Được đề xuất
Medical Infusion Pumps and Patient Monitors
Medical devices with touch input, such as infusion pumps and compact patient monitors, need a controller with predictable, repeatable readings and clear supply behaviour. The ADS7846E differential measurement across the X+/X− and Y+/Y− electrodes reduces sensitivity to common-mode supply noise on long panel tails, which is valuable in equipment with switching regulators and isolation barriers nearby. The direct battery measurement feature supports the backup-battery health checks typical of hospital equipment, while the on-chip temperature sensor provides the die temperature information needed for internal diagnostics and logging. The -40 °C to +85 °C operating range suits equipment stored and operated across varied clinical environments.
Được đề xuất
Battery-Powered Panel Equipment
The ADS7846E is a natural fit for battery-operated products such as handheld readers, portable test gear and battery-powered industrial terminals, because its auxiliary channel can measure the cell voltage directly through the same converter used for touch. That allows accurate state-of-charge reporting without adding a second analog front end or a dedicated fuel gauge. The programmable internal reference lets the firmware scale both touch and battery readings consistently as the pack voltage sags, and the low 2.7 V minimum supply lets the design operate directly from a single-cell lithium pack through a low-dropout regulator without an unnecessary boost stage.
Được đề xuất
Educational and Kitchen Appliance Touch Panels
Consumer-grade appliances, educational instruments and smart-home control pads often use inexpensive 4-wire resistive panels where a capacitive controller would be over-specified. The ADS7846E delivers a functional touch interface from a 16-pin SSOP with only four SPI lines, and the 125 kHz throughput gives a responsive feel even on low-cost panels with higher sheet resistance. Direct battery or supply measurement can be used to drive on-screen battery icons or to detect supply brownout before the display controller resets. The internal reference being programmable also allows the firmware to calibrate the panel offsets and full-scale endpoints in production without a trimmer.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho ADS7846E — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | ADS7843E | TSC2046E | ADS7842EB |
|---|---|---|---|---|
| Package | SSOP-16 | SSOP-16 - same footprint | SSOP-16 - same footprint | SSOP-16 - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Controller Type | 4-wire resistive touch screen controller | 4-wire resistive touch screen controller | 4-wire resistive touch screen controller | 4-wire resistive touch screen controller |
| Digital Interface | SPI, 4-wire | SPI, 4-wire | SPI | SPI |
| Direct Battery Measurement | Yes, auxiliary channel | No | No | No |
| On-Chip Temperature Sensor | Yes | No | No | No |
Bảo phân biệt quan trọng
- Adds direct battery measurement and on-chip temperature sensing that the pin-compatible predecessor does not provide (vsADS7843E)
- Programmable internal reference removes the need for an external precision reference in new designs (vsTSC2046E)
- Maintains a defined upgrade path from the legacy 4-wire resistive ecosystem (vsADS7842EB)
Ghi chú thiết kế
Route the four panel electrodes (X+, X−, Y+, Y−) as a matched, tightly coupled group directly from the touch tail connector to the controller pins, and keep them short. Long, loosely coupled traces act as antennas and pick up display backlight converter switching noise, which appears as unstable coordinates. If the tail must be long, add a guard trace driven from the analog ground between the electrode pairs, and place a small bypass capacitor at the controller supply pin with the shortest possible return path to the ground plane.
The controller measures the differential voltage across the panel electrodes, so common-mode noise on the panel is rejected while differential pickup is not. Keep the touch interface away from switching regulators, display drivers and high-current relay or motor traces; if separation is impossible, shield with a grounded guard and add panel averaging in firmware. Because the SAR converter samples a moving reference, allow the acquisition and settling cycles described in the datasheet before issuing a read command, otherwise coordinates will shift with panel temperature and supply level.
Estimated: the analog supply dissipation of the controller itself is small, but the reference and converter circuitry draw current that varies with conversion activity, and this ripple appears directly on the panel excitation. Power the analog rail from a clean 2.7 V to 5.25 V source with local 0.1 uF and 1 uF ceramic bypass capacitance placed at the supply and ground pins. When the design uses direct battery measurement through the auxiliary channel, note that the measured battery voltage includes any drop across the protection and regulation path, so calibrate the firmware offsets accordingly.
Two mistakes recur in touch panel designs. First, swapping the ADS7846 into an existing ADS7843 board without reviewing the reference configuration and the software initialization sequence, since the added battery and temperature channels change the command set and register defaults. Second, treating the raw 12-bit result as an absolute coordinate: panel tolerances, tail resistance and the overlay stack shift the mapping, so always run a two-point or multi-point calibration against the visible bezel during production. Also verify the AC timing of the SPI clock against the host processor timing before ramping to volume.
Thông tin tuân thủ
Compliance status for RoHS, REACH, lead-free finish, halogen-free and conflict minerals is not stated on the manufacturer pages for this part, so it is reported as unknown. The ADS7846E is an industrial-temperature analog interface device and is not presented as an AEC-Q100 qualified automotive part. Confirm the terminal-finish and material compliance documents for the exact ordering suffix before committing to a regulated shipment.