Part A
ADS7844NB/1K
Texas Instruments
- Lifecycle
- Active
- Stock
- 5039 PCS
- Package
- SSOP-20
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Not a drop-in replacement
The ADS7844NB/1K and ADS7842EB are not drop-in replacements for one another. Although both are 12-bit successive-approximation ADCs from Texas Instruments, they differ in channel configuration, analog input architecture, package footprint, and serial interface framing, so a direct board-level substitution is not possible without redesign.
Different channel configuration
Different input architecture
Different package footprint
Different interface framing
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS7844NB/1K | ADS7842EB | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so conversion resolution is equivalent for substitutability. |
| Number of Input Channels | 8 single-ended / 4 differential | 4 single-ended / 2 differential | Channel count determines how many signals can be multiplexed; the ADS7844 supports twice as many inputs. |
| Sampling Rate | 200 kSPS | 200 kSPS | Throughput must meet system timing; both offer the same maximum sampling rate. |
| Interface Type | SPI / Serial | Parallel | The digital interface must match the host controller; SPI versus parallel is a major architectural difference. |
| Supply Voltage | 2.7 V to 5.25 V | 5 V (single supply) | Operating voltage range affects compatibility with system power rails and logic levels. |
| Package / Mounting | 20-SSOP (surface mount) | 28-SSOP (surface mount) | Footprint and pin count must match the PCB layout for a drop-in replacement. |
| Input Type | Single-ended / Pseudo-differential | Single-ended / Differential | Input configuration affects signal conditioning and measurement topology. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range must cover the application environment for reliable operation. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7844NB/1K | ADS7842EB |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Active |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 200k | 200k |
| Number of Inputs | 4, 8 | 4 |
| Input Type | Differential, Single Ended | Single Ended |
| Data Interface | SPI | Parallel |
| Configuration | MUX-S/H-ADC | MUX-S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External | External |
| Voltage - Supply, Analog | 2.7V ~ 3.6V, 5V | 2.7V ~ 3.6V, 5V |
| Voltage - Supply, Digital | 2.7V ~ 3.6V, 5V | 2.7V ~ 3.6V, 5V |
| Features | - | Selectable Address |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the ADS7844NB/1K and the ADS7842EB?
The ADS7844NB/1K is an 8-channel, 12-bit successive-approximation ADC with a serial SPI/QSPI/Microwire interface, housed in a 20-pin SSOP package and specified over the -40°C to +85°C industrial temperature range. The ADS7842EB is a 4-channel, 12-bit successive-approximation ADC with a parallel interface, housed in a 28-pin SSOP package and specified over the -40°C to +85°C industrial temperature range. The primary differences are channel count (8 vs 4), digital interface (serial vs parallel), and package pin count (20 vs 28).
Can the ADS7844NB/1K and ADS7842EB be used as direct substitutes for each other?
No. The two devices differ in channel count, digital interface type (serial versus parallel), and package pin count and pinout, so they are not pin-compatible or functionally interchangeable without redesign of the host interface and PCB layout.
What is the resolution and architecture of both converters?
Both the ADS7844NB/1K and the ADS7842EB are 12-bit successive-approximation register (SAR) analog-to-digital converters, providing 12-bit resolution over their respective input channels.
What digital interface does each device use?
The ADS7844NB/1K uses a serial interface compatible with SPI, QSPI, and Microwire protocols. The ADS7842EB uses a parallel digital interface for connection to a host processor bus.
How many analog input channels does each device provide?
The ADS7844NB/1K provides 8 analog input channels. The ADS7842EB provides 4 analog input channels.
What are the package and temperature range specifications?
The ADS7844NB/1K is supplied in a 20-pin SSOP package. The ADS7842EB is supplied in a 28-pin SSOP package. Both devices are specified for operation over the -40°C to +85°C industrial temperature range.
What supply voltage do these converters require?
Both the ADS7844NB/1K and the ADS7842EB operate from a single +5 V analog supply, with a separate digital supply pin for interfacing to the host logic level.