Part A
ADS7844EB
德州儀器
- Lifecycle
- Active
- Stock
- 3681 件
- Package
- SSOP-20
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Compatible functional replacement candidate
The ADS7844EB and ADS7842EB are both 12-bit successive-approximation ADCs from Texas Instruments in the same SSOP-20 package and share a compatible serial interface, making the ADS7842EB a viable functional replacement candidate for the ADS7844EB in many designs. However, the two devices differ in channel configuration and analog input architecture, so the replacement is not a direct drop-in and requires validation of the input multiplexer configuration and sampling network against the target application.
Resolution and ADC Architecture
High match
Package Type
High match
Channel Count and Input Configuration
Validation required
Analog Input Type
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADS7844EB | ADS7842EB | Why it matters |
|---|---|---|---|
| Number of Input Channels | 8 single-ended / 4 differential | 4 single-ended / 2 differential | Determines how many analog signals can be multiplexed into the ADC; a direct constraint on system channel count and substitutability. |
| Resolution | 12 bits | 12 bits | Sets the quantization step and achievable measurement precision; identical resolution means comparable accuracy potential. |
| Sampling Rate | 200 kSPS | 200 kSPS | Defines the maximum signal bandwidth that can be digitized; matching rates preserve timing and throughput compatibility. |
| Supply Voltage | 2.7 V to 5.25 V | 2.7 V to 5.25 V | Must match the system power rail; identical ranges allow drop-in use across the same supply designs. |
| Interface Type | SPI / Serial | SPI / Serial | Determines host compatibility and firmware protocol; matching serial interfaces simplify substitution. |
| Package / Pin Count | 20-pin SSOP | 20-pin SSOP | Footprint and pinout must align for board-level interchangeability; package differences affect layout and assembly. |
| Input Configuration | Single-ended and differential | Single-ended and differential | Affects how sensor signals are wired and common-mode rejection; differing channel counts change usable input topologies. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Ensures reliable operation across environmental conditions; matching ranges support the same application environments. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADS7844EB | 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 architectural differences between the ADS7844EB and ADS7842EB?
The ADS7844EB is an 8-channel, 12-bit successive-approximation register (SAR) analog-to-digital converter with a single-ended or differential input multiplexer. The ADS7842EB is a 4-channel, 12-bit SAR ADC with a 2-channel differential input multiplexer. Both devices are pin-compatible in the same 20-lead SSOP package but differ in channel count and input configuration.
Are the ADS7844EB and ADS7842EB pin-to-pin compatible?
Yes. Both devices are offered in a 20-lead SSOP (DB) package with the same pinout, allowing the ADS7842EB to be used as a drop-in replacement for the ADS7844EB when the reduced channel count and differential input configuration are acceptable for the application.
What is the maximum sampling rate of each device?
Both the ADS7844EB and ADS7842EB support a throughput rate of up to 200 kSPS when operating from a 5 V supply. The maximum conversion rate depends on the external clock frequency and the serial interface timing used in the system.
What analog input configurations does each converter support?
The ADS7844EB provides 8 input channels that can be configured as 8 single-ended inputs or 4 differential input pairs. The ADS7842EB provides 4 input channels configurable as 4 single-ended inputs or 2 differential input pairs. Both use a multiplexer preceding the SAR converter core.
Do the ADS7844EB and ADS7842EB use the same serial interface?
Yes. Both devices use a 4-wire SPI-compatible serial interface with CS, DIN, DOUT, and DCLK signals, supporting daisy-chain connection of multiple converters. The command word format and timing are compatible between the two devices.
What are the supply voltage and reference requirements for these ADCs?
Both the ADS7844EB and ADS7842EB operate from a single 2.7 V to 5.25 V analog supply (VCC) and a separate 2.7 V to 5.25 V digital supply (VDD). Each requires an external reference voltage applied to the VREF pin, with the reference range typically from 1.2 V to VCC.
What are the power consumption characteristics of the ADS7844EB and ADS7842EB?
Both devices feature a low-power SAR architecture with typical power dissipation of approximately 4.5 mW at a 200 kSPS throughput rate and 5 V supply. They also support a power-down mode that reduces supply current to a few microamperes between conversions for battery-powered applications.
In what applications would the ADS7842EB be preferred over the ADS7844EB?
The ADS7842EB is preferred when the system requires only 4 analog input channels or 2 differential pairs, such as in touch-screen controllers, battery monitoring, or compact sensor interfaces. The ADS7844EB is better suited for applications needing 8 single-ended channels or 4 differential pairs, such as multi-axis industrial monitoring or data acquisition systems.