ADI AD7891ASZ-1

Eight analog input channels, a complete conversion chain, and a single +5V supply — the ADI AD7891ASZ-1 addresses the most common constraint in multi-channel military and industrial data acquisition design: how to digitize multiple sensor inputs with minimum external component count and maximum interface flexibility. The -1 input range variant covers ±5V and ±10V bipolar inputs directly, matching the output ranges of most industrial transducers and military sensor conditioning circuits without external attenuation or level shifting. The ±17V overvoltage protection on each unselected channel is a design margin that matters in field-deployed systems where sensor cable faults and transient events are not hypothetical.

AD7891ASZ-1 Architecture: Complete Data Acquisition on a Single Die

The integration level of the AD7891 is what distinguishes it from ADC-only solutions in multi-channel acquisition designs. The 8:1 multiplexer, track-and-hold amplifier, 12-bit SAR ADC, and 2.5V reference are all on the same LC2MOS monolithic chip, with the reference available at an external pin for use by other signal chain components. Channel selection is controlled by a 3-bit address on MUX_A, MUX_B, and MUX_C inputs — directly compatible with GPIO outputs on most military microcontrollers and FPGAs. The 1 µs multiplexer settling time limits channel-hopping throughput to 62.5 kSPS across all eight channels, but at 500 kSPS on a single channel, the ADC core itself is not the bottleneck for single-channel or two-channel acquisition applications. For designs requiring a precision external reference to drive the REFIN pin, the 5962-9078501MLA AD780S provides a 2.5V reference with 3 ppm/°C maximum drift — a compatible precision reference source for the AD7891’s REFIN input within the same military qualification framework.

AD7891ASZ-1 vs AD7891ASZ-2: Input Range Selection

The AD7891 family offers two input range models that are otherwise identical:

The AD7891ASZ-1 is the correct selection when the signal sources are bipolar — bridge sensors with differential outputs, LVDT signal conditioners, or military analog buses operating at ±10V. The AD7891ASZ-2 suits single-supply system designs where all signals are positive and the supply rail is the upper reference boundary. For single-channel precision applications at higher resolution, the AD7690BRMZ 18-bit PulSAR ADC is the appropriate step up in resolution.

Sourcing the ADI AD7891ASZ-1

The AD7891ASZ-1 maintains consistent demand in industrial and defense data acquisition programs where 8-channel integration on a single chip reduces BOM complexity. We carry verified inventory with full lot traceability and anti-counterfeit inspection on every order. Contact us today to confirm availability and request a quote — our team responds within 24 hours.

• Eight channels on one die — eliminates 7 discrete ADC packages versus single-channel alternatives
• MODE pin interface selection requires no external logic to switch between parallel and serial bus modes
• ±17V overvoltage protection on unselected channels — survives sensor cable faults without damage
• On-chip 2.5V reference available at REFIN pin for external signal chain use
• Software and hardware convert start both supported — flexible triggering for synchronous and asynchronous acquisition
• Channel address held in internal register — allows channel pre-selection before conversion start
• Pin-compatible with AD7891ASZ-2 for input range migration without PCB redesign
• Full lot traceability and anti-counterfeit inspection on every order

Frequently Asked Questions (FAQ)

What Is the ADI AD7891ASZ-1 and How Does It Differ From the AD7891ASZ-2?

The AD7891ASZ-1 is a complete 8-channel, 12-bit, 500 kSPS data acquisition system in a 44-lead MQFP package, rated for –40°C to +85°C industrial operation. The -1 suffix specifies ±5V and ±10V bipolar input ranges with ±17V overvoltage protection — suited for bipolar sensor outputs and military analog signal levels. The AD7891ASZ-2 uses unipolar ranges of 0V to +2.5V, 0V to +5V, and ±2.5V with ±7V overvoltage protection — suited for single-supply signal chains. Both are otherwise identical in architecture, interface, and package.

How Does the AD7891ASZ-1 Dual-Mode Interface Work?

The MODE pin determines the interface type. When MODE is high, the AD7891 uses a standard parallel 12-bit interface with bus access time under 40 ns, compatible with 8-bit and 16-bit processor buses. When MODE is low, the device switches to a serial SPI/MICROWIRE-compatible interface. Both modes use the same package pins — no hardware changes are required to switch interface modes, only the MODE pin state and the firmware interface code.

What Is the Maximum Throughput When Scanning All Eight Channels?

The 8-channel scanning throughput is 62.5 kSPS per channel, limited by the 1 µs multiplexer settling time between channel switches. On a single channel with no channel hopping, the ADC achieves its full 500 kSPS throughput using a hardware convert start. For designs requiring higher per-channel throughput across multiple channels, external multiplexers ahead of a faster single-channel ADC such as the AD7690BRMZ provide an alternative architecture.

Does the AD7891ASZ-1 Require an External Reference?

No. The 2.5V on-chip reference drives the ADC core and is available at the REFIN pin for external use. An external reference can override the internal reference by driving the REFIN pin — useful when the internal reference drift is insufficient for the system accuracy budget. The internal reference is accurate to ±10 mV maximum and is adequate for most industrial and defense 12-bit acquisition applications.

How Do I Request a Quote for the ADI AD7891ASZ-1?

Submit an inquiry through our website contact form or email our sales team directly. We will respond within 24 hours with pricing, availability, and lead time — and can discuss long-term supply agreements for production programs.