Part A
ADS7870EA
Техасские инструменты
- Lifecycle
- Active
- Stock
- 3964 ПКС
- Package
- SSOP-28
- Series
- Сбор данных - ADC-DAC - Специальное назначение
Replacement verdict
Not a drop-in replacement
The ADS7870EA and ADS7842E/1KG4 are not drop-in replacements for one another. The ADS7870EA is a 12-bit, 8-channel data acquisition system with an integrated multiplexer, programmable gain amplifier, and serial interface, while the ADS7842E/1KG4 is a 12-bit, 4-channel successive-approximation ADC with a parallel interface. Their channel count, interface type, and package footprint differ, so a direct board-level substitution is not possible without redesign.
Different channel count
Different interface type
Different package footprint
Different input architecture
Parts at a glance
Part B
ADS7842E/1KG4
Техасские инструменты
- Lifecycle
- Active
- Stock
- 9177 ПКС
- Package
- SSOP-28
- Series
- Сбор данных - аналогово-цифровые преобразователи (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 | ADS7842E/1KG4 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 12 | 12 | Both are 12-bit converters, so nominal resolution is equivalent for substitutability. |
| Number of ADC channels | 8 (single-ended) / 4 (differential) | 4 (single-ended) | Channel count determines how many analog signals can be multiplexed into one device; the ADS7870 offers more inputs. |
| Sampling rate (max) | 52 kSPS | 200 kSPS | Maximum throughput affects whether the part can handle faster-changing signals in the target application. |
| Interface type | SPI / serial (QSPI, Microwire compatible) | Parallel | The digital interface must match the host controller; serial versus parallel is a fundamental compatibility difference. |
| Integrated programmable gain amplifier (PGA) | Yes | No | An on-chip PGA allows direct connection of small signals without external amplification, affecting system complexity. |
| Supply voltage (analog) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Compatible supply ranges simplify power-rail reuse when substituting one part for the other. |
| Package | 28-pin SSOP | 20-pin SSOP | Different pin counts and footprints require board layout changes, so they are not drop-in replacements. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Matching temperature ranges ensure both parts suit the same environmental conditions. |
| Internal reference | Yes (on-chip reference) | No (external reference required) | An internal reference reduces external component count; absence of one requires an added reference circuit. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7870EA | ADS7842E/1KG4 |
|---|---|---|
| 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 | Parallel |
| 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 |
| Features | - | Selectable Address |
| 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
What are the primary functional differences between the ADS7870EA and the ADS7842E/1KG4?
The ADS7870EA is a complete data acquisition system (DAS) that integrates a 12-bit successive-approximation ADC, a 4-channel differential/8-channel single-ended input multiplexer, a programmable gain amplifier, and a precision voltage reference in a single package. The ADS7842E/1KG4 is a standalone 12-bit, 4-channel sampling analog-to-digital converter that requires external signal conditioning and reference components. The ADS7870EA targets integrated multi-channel data acquisition, while the ADS7842E/1KG4 targets applications needing a discrete 4-channel ADC with a parallel interface.
Do the ADS7870EA and ADS7842E/1KG4 use the same digital interface?
No. The ADS7870EA communicates via a serial SPI-compatible interface, which reduces pin count and simplifies isolation. The ADS7842E/1KG4 provides a parallel digital output interface for direct connection to a microprocessor or DSP data bus. The interface architectures are not interchangeable, so the host system's digital bus must match the selected device.
How do the input channel configurations compare between the two devices?
The ADS7870EA offers an 8-channel single-ended or 4-channel differential input multiplexer with programmable gain, allowing direct connection of low-level sensors. The ADS7842E/1KG4 provides 4 single-ended analog input channels. Designs requiring differential inputs or on-chip gain should use the ADS7870EA, while the ADS7842E/1KG4 suits single-ended, 4-channel sampling applications.
Are the ADS7870EA and ADS7842E/1KG4 pin-to-pin or package compatible?
No. The ADS7870EA is supplied in a 28-pin SSOP package, while the ADS7842E/1KG4 is supplied in a 20-pin SSOP package. The differing pin counts, pin functions, and PCB land patterns prevent a direct drop-in replacement. A redesign of the PCB footprint and signal routing is required when switching between these devices.
Do both devices include an internal voltage reference?
The ADS7870EA integrates an on-chip precision voltage reference, which reduces external component count for ratiometric or absolute measurements. The ADS7842E/1KG4 does not include an internal reference and requires an external reference voltage to be supplied to the REF pin. Designs using the ADS7842E/1KG4 must allocate board space and cost for an external reference device.
What are the supply voltage and resolution specifications for each device?
Both devices are 12-bit successive-approximation ADCs. The ADS7870EA operates from a single 5 V analog supply with a separate digital supply, while the ADS7842E/1KG4 operates from a single 5 V supply. Both provide 12-bit resolution; however, overall accuracy depends on the reference source and input configuration, so the system designer must verify noise, gain error, and offset against the datasheet for the target application.
Which device is better suited for multi-channel sensor data acquisition?
The ADS7870EA is generally better suited for multi-channel sensor data acquisition because it combines an 8-channel single-ended/4-channel differential multiplexer, a programmable gain amplifier, a 12-bit ADC, and an internal reference in one package. The ADS7842E/1KG4 is a 4-channel single-ended ADC without integrated gain or reference, making it more appropriate for simpler 4-channel sampling tasks where external signal conditioning is already present.
Can the ADS7870EA and ADS7842E/1KG4 be used interchangeably in an existing design?
No. Differences in package pin count, digital interface (serial versus parallel), input multiplexer configuration, and internal reference availability mean the two devices are not interchangeable without a board redesign and firmware changes. A direct substitution is not supported by the manufacturer datasheets, and any replacement must be validated against the target system's electrical and timing requirements.