Part A
ADS7843E/2K5
STマイクロエレクトロニクス
- Lifecycle
- Active
- Stock
- 2859 個数
- Package
- SSOP-16
- Series
- データ取得 - タッチスクリーンコントローラ
Replacement verdict
Not a drop-in replacement
The ADS7843E/2K5 and ADS7844E/2K5G4 are not drop-in replacements for one another. Although both are 12-bit successive-approximation ADCs in the same 16-pin SSOP package, they differ in input architecture, channel count, and interface configuration, so the ADS7844E/2K5G4 cannot be substituted directly for the ADS7843E/2K5 in an existing design without schematic and firmware changes.
Different input architecture
Different channel count
Different interface configuration
Different conversion control
Parts at a glance
Part B
ADS7844E/2K5G4
STマイクロエレクトロニクス
- Lifecycle
- Active
- Stock
- 2200 個数
- Package
- SSOP-20
- Series
- データ取得 - アナログ/デジタルコンバータ (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS7843E/2K5 | ADS7844E/2K5G4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 12 | 12 | Both are 12-bit devices, so resolution alone does not distinguish them for substitutability. |
| Number of input channels | 4 (single-ended) / 2 (differential) | 8 (single-ended) / 4 (differential) | The ADS7844 provides twice the channel count, which is critical when more analog inputs must be sampled. |
| Interface type | SPI (serial) | SPI (serial) | Both use a serial SPI-compatible interface, so the host microcontroller connection is functionally similar. |
| Supply voltage range | 2.7 V to 5.25 V | 2.7 V to 5.25 V | Identical supply range means both can operate from the same system rails without level shifting. |
| Internal reference | No (external reference required) | No (external reference required) | Both require an external reference, so the reference design must be carried over when substituting. |
| Package type | SSOP-16 | SSOP-20 | Different package pin counts and footprints mean the PCB layout cannot be shared directly between the two parts. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Matching temperature ranges confirm both are suitable for the same industrial-grade environments. |
| Typical application focus | Touch-screen digitizer controller | General-purpose multi-channel ADC | The ADS7843 is optimized for touch-screen sensing while the ADS7844 targets general analog acquisition, affecting functional substitutability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7843E/2K5 | ADS7844E/2K5G4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | - | 12 |
| Sampling Rate(Per Second) | - | 200k |
| Number of Inputs | - | 4, 8 |
| Input Type | - | Differential, Single Ended |
| Data Interface | - | SPI |
| Configuration | - | MUX-S/H-ADC |
| Ratio - S / H: ADC | - | 1:1 |
| Number of A/D Converters | - | 1 |
| Architecture | - | SAR |
| Reference Type | - | External |
| Voltage - Supply, Analog | - | 2.7V ~ 3.6V, 5V |
| Voltage - Supply, Digital | - | 2.7V ~ 3.6V, 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Touchscreen | 4 Wire Resistive | - |
| Resolution(Bits) | 12 b | - |
| Interface | Serial | - |
| Voltage Reference | External | - |
| Voltage - Supply | 2.7V ~ 5V | - |
| Supply Current | 2.5 µA | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
What are the key differences between the ADS7843E/2K5 and the ADS7844E/2K5G4?
The ADS7843E/2K5 is a 4-wire resistive touch screen controller with a 12-bit SAR ADC and an SPI-compatible serial interface, supplied in a 16-pin SSOP package and delivered on a 2,500-unit tape and reel. The ADS7844E/2K5G4 is an 8-channel, 12-bit SAR ADC with a serial interface, supplied in a 20-pin SSOP package and delivered on a 2,500-unit tape and reel with the "G4" suffix indicating lead-free (Pb-free) construction. The ADS7843 is application-specific for touch screen digitizing, while the ADS7844 is a general-purpose multi-channel ADC.
Can the ADS7843E/2K5 and ADS7844E/2K5G4 be used interchangeably in the same socket?
No. The two devices have different pin counts and package sizes (16-pin SSOP for the ADS7843 versus 20-pin SSOP for the ADS7844), different pin functions, and different functional architectures (touch screen controller versus 8-channel ADC). They are not pin-compatible or functionally interchangeable, and substitution requires a PCB redesign and firmware changes.
What is the resolution and architecture of each device?
Both devices use a successive-approximation register (SAR) ADC architecture with 12-bit resolution. The ADS7843E/2K5 provides 12-bit resolution for touch screen coordinate measurement, while the ADS7844E/2K5G4 provides 12-bit resolution across its 8 analog input channels.
How many analog input channels does each device support?
The ADS7843E/2K5 is designed for 4-wire resistive touch screen panels and provides the drive and sense lines for X and Y coordinate measurement plus a pen-interrupt input. The ADS7844E/2K5G4 provides 8 analog input channels that can be configured as single-ended or differential inputs, making it suitable for general-purpose multi-channel data acquisition.
What serial interface do these devices use?
Both the ADS7843E/2K5 and the ADS7844E/2K5G4 use an SPI-compatible serial interface for communication with a host microcontroller or processor. The interface supports standard serial clock, data-in, data-out, and chip-select signals.
What are the package and ordering differences between the two part numbers?
The ADS7843E/2K5 is supplied in a 16-pin SSOP package on a 2,500-unit tape and reel. The ADS7844E/2K5G4 is supplied in a 20-pin SSOP package on a 2,500-unit tape and reel, with the "G4" suffix denoting lead-free (Pb-free) construction. Designers must verify package footprint and lead-free process compatibility against their assembly requirements.
Which device should be selected for a resistive touch screen application versus a multi-channel sensor application?
For a 4-wire resistive touch screen application, the ADS7843E/2K5 is the application-specific choice because it integrates the touch panel drive and coordinate measurement functions. For general-purpose multi-channel analog acquisition requiring up to 8 input channels, the ADS7844E/2K5G4 is the appropriate choice. Selection should be confirmed against the target system's channel count, interface, and package requirements using the respective manufacturer datasheets.