Part A
ADS7870EA
Texas Instruments
- Lifecycle
- Active
- Stock
- 3964 Stückzahl
- Package
- SSOP-28
- Series
- Datenerfassung von ADCs-DACs für besonderen Zweck
Replacement verdict
Not a drop-in replacement
The ADS7870EA and ADS7844EG4 are not drop-in replacements for one another. Although both are 12-bit successive-approximation ADCs from Texas Instruments, they differ in serial interface protocol, package footprint, and integrated feature set, so a direct board-level substitution is not possible without redesign.
Different serial interface
Different package footprint
Different integrated features
Different channel configuration
Parts at a glance
Part B
ADS7844EG4
Texas Instruments
- Lifecycle
- Active
- Stock
- 6438 Stückzahl
- Package
- SSOP-20
- Series
- Datenerfassung mit Analog to Digital Converters (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 | ADS7870EA | ADS7844EG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 12 | 12 | Both are 12-bit, so nominal measurement precision is equivalent. |
| Number of ADC channels | 8 single-ended / 4 differential | 8 single-ended / 4 differential | Channel count determines how many analog signals can be multiplexed into one converter. |
| Sampling rate (max) | 52 kSPS | 200 kSPS | Higher throughput allows faster signal acquisition and wider bandwidth applications. |
| Interface type | SPI / serial (with on-chip PGA and reference) | SPI / serial | Interface compatibility determines whether the part can drop into an existing digital bus design. |
| On-chip programmable gain amplifier (PGA) | Yes | No | An integrated PGA allows direct amplification of small signals, affecting system architecture and external component count. |
| On-chip voltage reference | Yes | No (external reference required) | An internal reference simplifies design and reduces board space; absence requires an external reference. |
| Supply voltage (analog) | 2.7 V to 5.5 V | 2.7 V to 5.25 V | Supply range affects compatibility with the system power rail and allowable signal swing. |
| Package | 28-pin SSOP | 20-pin SSOP | Different package pin counts and footprints prevent direct board-level substitution. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings mean both suit the same industrial environments. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7870EA | ADS7844EG4 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Discontinued at Digi-Key |
| Number of Bits | - | 12 |
| Sampling Rate(Per Second) | 52k | 200k |
| Number of Inputs | - | 4, 8 |
| Input Type | - | Differential, Single Ended |
| Data Interface | Serial | 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 |
| Type | Data Acquisition System (DAS) | - |
| Number of Channels | 8 | - |
| Resolution(Bits) | 12 b | - |
| Voltage Supply Source | Single Supply | - |
| Voltage - Supply | 2.7V ~ 5.5V | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
Are the ADS7870EA and ADS7844EG4 functionally interchangeable?
No. The ADS7870EA is a 12-bit data acquisition system with an integrated multiplexer, programmable gain amplifier, and internal reference, while the ADS7844EG4 is a 12-bit 8-channel sampling analog-to-digital converter without an integrated PGA or internal reference. Their architectures and feature sets differ, so they are not direct functional equivalents.
How do the analog input configurations differ between the ADS7870EA and ADS7844EG4?
The ADS7870EA provides a 4-channel differential or 8-channel single-ended input multiplexer with a programmable gain amplifier. The ADS7844EG4 provides an 8-channel single-ended or 4-channel differential input multiplexer without an integrated PGA. The input flexibility differs, so system-level signal conditioning requirements must be re-evaluated when comparing them.
Do the ADS7870EA and ADS7844EG4 use the same package and pinout?
No. The ADS7870EA is offered in a 28-pin SSOP package, while the ADS7844EG4 is offered in a 20-pin SSOP package. The pin counts and pin functions differ, so PCB land patterns and pin assignments are not compatible between the two devices.
What are the resolution and sampling characteristics of each device?
Both devices provide 12-bit resolution. The ADS7870EA is specified for operation with a serial interface and includes an integrated PGA and reference, while the ADS7844EG4 is a 12-bit sampling ADC with a serial interface and requires an external reference. Sampling rate and throughput specifications should be verified against the respective manufacturer datasheets for the target operating conditions.
Can the ADS7844EG4 be used as a drop-in replacement for the ADS7870EA?
No. Because the ADS7870EA integrates a programmable gain amplifier and internal reference that the ADS7844EG4 does not, and because the packages and pinouts differ, a drop-in replacement is not possible. Any substitution requires redesign of the analog front end, reference circuitry, and PCB layout.
Do both devices support a serial digital interface?
Yes. Both the ADS7870EA and ADS7844EG4 provide a serial digital interface for communication with a host controller. However, the specific interface protocol, timing, and register set differ between the two devices, so firmware and driver software must be adapted accordingly.
Which device includes an internal voltage reference?
The ADS7870EA includes an internal voltage reference as part of its integrated data acquisition system. The ADS7844EG4 does not include an internal reference and requires an external reference voltage to be supplied for conversion. This difference affects system component count and accuracy budgeting.