Part A
AD977ABRS
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1992 PCS
- Package
- SSOP-28
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD977CRS is a functionally compatible replacement candidate for the AD977ABRS, sharing the same 16-bit SAR ADC architecture, pinout, and package family, with the CRS grade offering tighter linearity and faster throughput specifications. Designers should validate the tighter DNL/INL and higher sampling rate against their system requirements before substituting in production.
Resolution and Architecture
High match
Package and Pinout
High match
Sampling Rate
Validation required
Linearity Grade
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 | AD977ABRS | AD977CRS | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both converters provide 16-bit resolution, so quantization noise floor and LSB size are equivalent for signal-chain budgeting. |
| Sampling Rate | 100 kSPS | 100 kSPS | Identical maximum throughput means neither part limits system update rate or Nyquist bandwidth for the same input signal. |
| INL (Integral Nonlinearity) | ±2.0 LSB max | ±1.0 LSB max | The C-grade offers tighter linearity, which directly improves absolute accuracy and reduces calibration effort in precision measurement designs. |
| DNL (Differential Nonlinearity) | ±1.0 LSB max | ±1.0 LSB max | Guaranteed no missing codes for both grades, so monotonicity behavior is equivalent across the two parts. |
| Input Type | Single-ended, bipolar | Single-ended, bipolar | Same analog input configuration allows a drop-in interface without redesigning the front-end signal conditioning. |
| Supply Voltage | 5 V (analog and digital) | 5 V (analog and digital) | Identical supply requirements mean the same power rails and decoupling network can be reused. |
| Interface | Parallel (byte/word) | Parallel (byte/word) | Same digital interface protocol ensures the host processor or FPGA glue logic remains compatible. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Equivalent industrial temperature ratings allow the same thermal and environmental qualification for either grade. |
| Package | 28-lead SSOP | 28-lead SSOP | Same footprint and pinout permit direct board-level substitution without layout changes. |
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 | AD977ABRS | AD977CRS |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Obsolete | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 200k | 100k |
| Number of Inputs | 1 | 1 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI | SPI |
| Configuration | ADC | ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD977ABRS and AD977CRS?
Both are 16-bit, 100 kSPS analog-to-digital converters from Analog Devices in a 28-lead SSOP package. The primary difference is the grade specification: the AD977ABRS is specified for a maximum integral nonlinearity (INL) of ±2 LSB, while the AD977CRS is specified for a maximum INL of ±1 LSB. The AD977CRS also carries tighter guaranteed specifications for parameters such as differential nonlinearity and gain error.
Are the AD977ABRS and AD977CRS pin-compatible?
Yes. Both devices are offered in the same 28-lead SSOP (RS) package and share an identical pinout, so they are pin-compatible and can be used on the same PCB footprint.
Can the AD977ABRS be replaced by the AD977CRS in an existing design?
In most cases yes, because the AD977CRS is a higher-grade version of the same converter with the same pinout and functional behavior. The AD977CRS offers tighter INL and DNL limits, so a design that works with the AD977ABRS will generally work with the AD977CRS, provided the application can accept the higher-grade specifications and the associated cost.
What is the resolution and throughput of these converters?
Both the AD977ABRS and AD977CRS are 16-bit successive-approximation ADCs with a maximum throughput of 100 kSPS.
What analog input range do the AD977ABRS and AD977CRS support?
Both devices accept a bipolar analog input range of ±10 V, with the input configuration set by external connections and the internal reference.
Do the AD977ABRS and AD977CRS have the same digital interface?
Yes. Both parts provide a parallel digital output interface and support the same conversion control and data read timing, so the digital interface is identical between the two grades.
What are the operating temperature ranges for the AD977ABRS and AD977CRS?
Both the AD977ABRS and AD977CRS are specified over the industrial temperature range of −40 °C to +85 °C.
Which grade should be selected for a new design requiring tighter linearity?
For applications requiring tighter linearity, the AD977CRS should be selected because it guarantees a maximum INL of ±1 LSB, whereas the AD977ABRS guarantees a maximum INL of ±2 LSB. The choice should be confirmed against the system error budget and the manufacturer datasheet.