Part A
ADS7846E
Texas Instruments
- Lifecycle
- Active
- Stock
- 5291 PCS
- Package
- SSOP-16
- Series
- Acquisition de données - Contrôleur à écran tactile
Replacement verdict
Not a drop-in replacement
The ADS7846E and ADS7844E/2K5G4 are not drop-in replacements for one another. Although both are 12-bit successive-approximation ADCs in the same TSSOP-20 package, they differ in integrated functionality, input configuration, and interface signaling, so a direct board-level substitution is not possible without design changes and validation.
Different integrated features
Different input configuration
Different interface signaling
Different conversion architecture
Parts at a glance
Part B
ADS7844E/2K5G4
Texas Instruments
- Lifecycle
- Active
- Stock
- 2200 PCS
- Package
- SSOP-20
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | ADS7846E | ADS7844E/2K5G4 | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit SAR ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Number of Input Channels | 4 (single-ended) / 2 (differential) | 8 (single-ended) / 4 (differential) | Channel count determines how many signals can be multiplexed into one ADC; the ADS7844 offers twice the input capacity. |
| Interface Type | SPI (3-wire serial) | SPI (3-wire serial) | Both use a serial SPI-compatible interface, so host microcontroller compatibility is 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. |
| Package / Pin Count | 16-pin SSOP (DBQ) | 20-pin SSOP (DBQ) | Different pin counts and footprints mean the parts are not drop-in PCB replacements for each other. |
| Sampling Rate | 125 kSPS | 200 kSPS | The ADS7844 supports a higher throughput, which matters for faster signal acquisition requirements. |
| On-Chip Reference | No (external reference required) | No (external reference required) | Both require an external voltage reference, so reference design effort is comparable. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings mean both suit the same industrial-grade environments. |
| Power Consumption (typical) | Low power, ~500 µA at 5 V | Low power, ~500 µA at 5 V | Comparable power draw makes both suitable for battery-powered or power-sensitive designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7846E | 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 | SPI | - |
| Voltage Reference | External, Internal | - |
| Voltage - Supply | 2.2V ~ 5.25V | - |
| Supply Current | 500 µA | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
What are the key differences between the ADS7846E and ADS7844E/2K5G4?
The ADS7846E is a 4-wire resistive touch screen controller with an integrated SPI interface, on-chip temperature sensor, and a 12-bit SAR ADC, housed in a 16-pin SSOP (DBQ) package. The ADS7844E/2K5G4 is an 8-channel, 12-bit SAR ADC with a serial interface, housed in a 20-pin SSOP (DB) package, and is supplied in tape-and-reel form (2K5). The ADS7846E is optimized for touch-screen digitizer applications, while the ADS7844E is a general-purpose 8-channel data acquisition ADC.
Are the ADS7846E and ADS7844E/2K5G4 pin-compatible?
No. The ADS7846E uses a 16-pin SSOP (DBQ) package, while the ADS7844E/2K5G4 uses a 20-pin SSOP (DB) package. The pin counts and pin functions differ, so they are not drop-in replacements and require different PCB footprints.
Do both devices use the same serial interface?
Both devices use a serial interface compatible with SPI, but their command and data formats differ. The ADS7846E uses a 24-clock-cycle conversion and control word format tailored for touch-screen coordinate and auxiliary measurements, while the ADS7844E uses an 8-channel multiplexer control word for general-purpose channel selection. Firmware must be adapted accordingly.
What is the resolution and sampling architecture of each device?
Both the ADS7846E and ADS7844E/2K5G4 are 12-bit successive-approximation register (SAR) ADCs. The ADS7846E provides 12-bit resolution for touch-screen X/Y position, auxiliary inputs, and temperature sensing. The ADS7844E provides 12-bit resolution across its 8 input channels.
Can the ADS7844E/2K5G4 be used as a touch-screen controller?
No. The ADS7844E/2K5G4 is a general-purpose 8-channel ADC and does not include the touch-screen-specific features of the ADS7846E, such as the integrated touch-screen driver switches, pen-interrupt output, and on-chip temperature sensor used for touch digitizer applications. For touch-screen control, the ADS7846E is the appropriate device.
What supply voltage range do these devices support?
Both the ADS7846E and ADS7844E/2K5G4 operate from a single supply in the range of 2.7 V to 5.25 V, with a separate reference input (VREF) that sets the full-scale input range. Designers should confirm the exact supply and reference conditions against the respective manufacturer datasheets for the target design.
What is the significance of the "2K5G4" suffix on the ADS7844E/2K5G4?
The "2K5" suffix indicates tape-and-reel packaging with 2,500 units per reel, and "G4" denotes a lead-free (Pb-free) Green-compliant package option. The ADS7846E is typically supplied in tube or tape-and-reel depending on the ordering code; designers should verify the specific ordering suffix for packaging and lead-free status.
Which device is better suited for multi-channel data acquisition?
The ADS7844E/2K5G4 is better suited for multi-channel data acquisition because it provides 8 input channels through an integrated multiplexer, whereas the ADS7846E is designed primarily for 4-wire resistive touch-screen control with a limited number of auxiliary inputs. For general-purpose 8-channel sensing, the ADS7844E is the appropriate choice.