Part A
ADS7870EA
STマイクロエレクトロニクス
- Lifecycle
- Active
- Stock
- 3964 個数
- Package
- SSOP-28
- Series
- データ取得 - ADC/DAC - 特殊用途向け
Replacement verdict
Not a drop-in replacement
The ADS7870EA and ADS7841ES/2K5G4 are not functionally interchangeable. The ADS7870EA integrates a 12-bit ADC with a programmable gain amplifier, multiplexer, and on-chip reference in a single package, while the ADS7841ES/2K5G4 is a standalone 12-bit 4-channel successive-approximation ADC without integrated signal conditioning. Their differing architectures, interface configurations, and package footprints require circuit redesign rather than direct substitution.
Different architecture
Different interface type
Different package footprint
Different input configuration
Parts at a glance
Part B
ADS7841ES/2K5G4
STマイクロエレクトロニクス
- Lifecycle
- Active
- Stock
- 7893 個数
- Package
- SSOP-16
- 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 | ADS7870EA | ADS7841ES/2K5G4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 12 | 12 | Both are 12-bit converters, so resolution alone does not differentiate them for substitutability. |
| Number of ADC input channels | 8 single-ended / 4 differential (with MUX) | 4 single-ended / 2 differential | The ADS7870 integrates an 8-channel multiplexer, allowing more signals to be measured without external muxing, which affects system architecture. |
| Interface type | SPI-compatible serial | SPI-compatible serial | Both use a serial SPI-style interface, so host microcontroller compatibility is similar. |
| Supply voltage (V) | 2.7 to 5.5 | 2.7 to 5.25 | Slightly different maximum supply voltage affects margin when operating near 5 V rails. |
| Integrated programmable gain amplifier (PGA) | Yes | No | The ADS7870 includes a PGA for small-signal amplification, while the ADS7841 does not, which is a major functional difference for sensor interfacing. |
| On-chip reference | Yes (internal reference) | No (external reference required) | An internal reference simplifies design and reduces external component count; the ADS7841 requires an external reference. |
| Package type | SSOP-28 | SSOP-16 | Different package sizes and pin counts mean the parts are not footprint-compatible and require different PCB layouts. |
| Operating temperature range (°C) | -40 to +85 | -40 to +85 | Identical industrial temperature ranges mean both suit the same environmental conditions. |
| Typical power consumption | Higher (includes PGA and reference circuitry) | Lower (simpler ADC core) | The added functionality of the ADS7870 increases power draw, which matters for low-power or battery-operated designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7870EA | ADS7841ES/2K5G4 |
|---|---|---|
| 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/2K5G4?
The ADS7870EA is a 12-bit data acquisition system that integrates a 12-bit SAR ADC, a 4-channel differential/8-channel single-ended input multiplexer, a programmable gain amplifier (PGA), and an on-chip reference, communicating via a serial interface. The ADS7841ES/2K5G4 is a standalone 12-bit SAR ADC with a 4-channel single-ended input multiplexer and a serial interface, without an integrated PGA or reference. The ADS7870EA is therefore a more highly integrated signal-conditioning solution, while the ADS7841ES/2K5G4 is a simpler, lower-channel-count ADC.
Do the ADS7870EA and ADS7841ES/2K5G4 have the same resolution and sampling rate?
Both devices are 12-bit successive-approximation ADCs. The ADS7870EA supports a maximum throughput of 52 kSPS, while the ADS7841ES/2K5G4 supports a maximum throughput of 200 kSPS. The ADS7841ES/2K5G4 therefore offers a significantly higher sampling rate, whereas the ADS7870EA trades throughput for integrated signal conditioning.
How do the input configurations of the ADS7870EA and ADS7841ES/2K5G4 differ?
The ADS7870EA provides a multiplexer configurable for 8 single-ended or 4 differential input channels, plus an integrated PGA with selectable gains. The ADS7841ES/2K5G4 provides a 4-channel single-ended input multiplexer without an integrated PGA. Designs requiring differential inputs or programmable gain should use the ADS7870EA, while single-ended, higher-speed measurements suit the ADS7841ES/2K5G4.
Are the ADS7870EA and ADS7841ES/2K5G4 pin-to-pin or package compatible?
No. The ADS7870EA is offered in a 28-pin SSOP package, while the ADS7841ES/2K5G4 is offered in a 16-pin SSOP package. The differing pin counts, pin functions, and package footprints mean the two devices are not drop-in replacements and require different PCB layouts.
What are the supply voltage and reference requirements for each device?
The ADS7870EA operates from a single 5 V supply and includes an on-chip reference, though an external reference can also be used. The ADS7841ES/2K5G4 operates from a single 2.7 V to 5 V supply and requires an external reference voltage applied to its VREF pin. Designs migrating between the two must account for the ADS7841ES/2K5G4's external reference requirement.
What serial interface do the ADS7870EA and ADS7841ES/2K5G4 use?
Both devices use a serial interface for communication with a host controller. The ADS7870EA uses a serial interface supporting microcontroller and DSP connection with dedicated control signals for channel selection and gain setting. The ADS7841ES/2K5G4 uses a standard SPI-compatible serial interface. System firmware and host port configuration must be adapted when substituting one device for the other.
Can the ADS7841ES/2K5G4 directly replace the ADS7870EA in an existing design?
No. Direct replacement is not possible because the devices differ in package pin count (16 vs 28 pins), input multiplexer configuration (4 single-ended vs 8 single-ended/4 differential), integrated PGA and reference availability, maximum throughput (200 kSPS vs 52 kSPS), and supply range. Any substitution requires a redesign of the PCB layout, reference circuitry, and firmware.
Which device is better suited for low-power, high-speed single-ended measurements?
The ADS7841ES/2K5G4 is better suited for low-power, high-speed single-ended measurements, as it supports up to 200 kSPS, operates from a 2.7 V to 5 V supply, and provides a 4-channel single-ended multiplexer in a compact 16-pin package. The ADS7870EA is preferable when integrated PGA, differential inputs, and an on-chip reference are required at lower throughput.