Part A
ADS7870EA
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 3964 PCS
- Package
- SSOP-28
- Series
- Data Acquisition - ADCs-DACs - Special Purpose
Replacement verdict
Not a drop-in replacement
The ADS7870EA and ADS7841ES/2K5 are not drop-in replacements for one another. Although both are Burr-Brown analog-to-digital converters in SOIC packages, they differ fundamentally in resolution, input architecture, interface protocol, and supply voltage range, so the ADS7841ES/2K5 cannot be substituted for the ADS7870EA without a full redesign of the surrounding circuitry and firmware.
Different resolution
Different input architecture
Different interface protocol
Different supply voltage range
Parts at a glance
Part B
ADS7841ES/2K5
Texas Dụng cụ
- Lifecycle
- Active
- Stock
- 8265 PCS
- Package
- SSOP-16
- Series
- Data Acquisition - 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 | ADS7841ES/2K5 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 12 | 12 | Both are 12-bit ADCs, so resolution is equivalent and not a differentiator for substitutability. |
| Number of ADC input channels | 8 single-ended / 4 differential (with on-chip MUX) | 4 single-ended / 2 differential | Channel count determines how many signals can be multiplexed into one converter; the ADS7870 supports twice the input count. |
| On-chip programmable gain amplifier (PGA) | Yes (gain 1–20) | No | A PGA allows direct amplification of small sensor signals, which the ADS7841 cannot do without external circuitry. |
| On-chip voltage reference | Yes (internal reference) | No (external reference required) | An internal reference simplifies the design and reduces external component count; the ADS7841 needs an external reference. |
| Sampling rate (max) | 52 kSPS | 200 kSPS | Maximum throughput affects how fast signals can be digitized; the ADS7841 is significantly faster. |
| Supply voltage range | 2.7 V to 5.5 V | 2.7 V to 5.25 V | Supply range determines compatibility with system rails; both are similar but the ADS7870 tolerates slightly higher voltage. |
| Digital interface | SPI-compatible serial | SPI-compatible serial | Both use a serial SPI-style interface, so host-side firmware and wiring are largely compatible. |
| Package | 28-pin SSOP | 16-pin SSOP | Different package pin counts and footprints mean the parts are not drop-in replacements on an existing PCB. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Both cover the industrial temperature range, so environmental compatibility is equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7870EA | ADS7841ES/2K5 |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Active | Obsolete |
| Number of Bits | - | 12 |
| Sampling Rate(Per Second) | 52k | 200k |
| Number of Inputs | - | 4 |
| Input Type | - | 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 ~ 125°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
What are the key architectural differences between the ADS7870EA and the ADS7841ES/2K5?
The ADS7870EA is a 12-bit data acquisition system (DAS) that integrates a 12-bit SAR ADC, a 4-channel differential/8-channel single-ended input multiplexer, a programmable gain amplifier (PGA), and a precision voltage reference in a single package. The ADS7841ES/2K5 is a standalone 12-bit SAR ADC with a 4-channel single-ended input multiplexer and an external reference requirement, without an integrated PGA or internal reference.
Do the ADS7870EA and ADS7841ES/2K5 have the same package and pinout?
No. The ADS7870EA is offered in a 28-pin SSOP package, while the ADS7841ES/2K5 is offered in a 16-pin SSOP package. The pin counts and pin functions differ, so they are not pin-compatible and cannot be dropped into the same PCB footprint.
What are the maximum sampling rates of these two ADCs?
The ADS7870EA supports a maximum throughput of 52 kSPS. The ADS7841ES/2K5 supports a maximum throughput of 200 kSPS. The ADS7841 is therefore significantly faster, while the ADS7870 integrates more signal-conditioning functions.
How do the input configurations differ between the ADS7870EA and ADS7841ES/2K5?
The ADS7870EA provides 8 single-ended or 4 differential input channels with a programmable gain amplifier offering gains of 1, 2, 4, 8, 16, 32, 64, and 128. The ADS7841ES/2K5 provides 4 single-ended input channels with a fixed unity-gain configuration and no integrated PGA.
Does either device include an internal voltage reference?
The ADS7870EA includes an on-chip precision voltage reference, which simplifies system design by reducing external component count. The ADS7841ES/2K5 requires an external reference voltage to be supplied to its VREF pin and does not include an internal reference.
What are the supply voltage requirements for the ADS7870EA and ADS7841ES/2K5?
The ADS7870EA operates from a single 5 V analog supply (with a separate digital supply pin). The ADS7841ES/2K5 operates from a single 2.7 V to 5.25 V supply, allowing it to interface directly with lower-voltage logic systems.
What serial interface do these devices use?
Both the ADS7870EA and the ADS7841ES/2K5 use a serial interface compatible with SPI and QSPI protocols. The ADS7870EA provides additional control registers accessible over the serial interface for configuring the multiplexer, PGA, and reference, whereas the ADS7841ES/2K5 uses a simpler command-based control word for channel selection and power-down modes.
In what applications would the ADS7870EA be preferred over the ADS7841ES/2K5?
The ADS7870EA is preferred in applications requiring integrated signal conditioning, such as multi-channel sensor data acquisition with low-level signals needing programmable gain, or systems where board space and external component count must be minimized. The ADS7841ES/2K5 is preferred in higher-speed, lower-channel-count applications where a simple external reference and a small 16-pin footprint are acceptable.