HI7191IBZ-T - 24-Bit Sigma-Delta ADC, SOIC-20 | Renesas
MPN: HI7191IBZ-T ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $25.32 | $25.32 |
| 10 | $23.5 | $235.00 |
| 100 | $21.1 | $2,110.00 |
| 500 | $19.2 | $9,600.00 |
| 1,000 | $17.4 | $17,400.00 |
HI7191IBZ-T Overview
A sigma-delta ADC is a type of oversampling converter that trades raw speed for very high resolution by pushing quantization noise to high frequencies where it can be digitally filtered away; the technique is widely used in precision measurement, weigh scales, sensor front-ends, and industrial instrumentation where DC accuracy and noise rejection matter more than bandwidth. The HI7191 belongs to the broader hierarchy of mixed-signal data converters (ADC -> sigma-delta ADC -> precision ADC -> data converter IC), and within Renesas it sits in the legacy Intersil precision-converter family.
Key features highlighted in the manufacturer datasheet include 24-bit no-missing-code resolution, integrated PGIA with gains of 1, 2, 4, 8, 16, 32, 64, and 128 eliminating the need for an external pre-amplifier, fully differential analog inputs, an on-demand converter that auto-calibrates on power-up, and a serial interface for digital readback. Industrial operating temperature range of -40 °C to +85 °C makes it suitable for factory-floor and process-control environments.
Typical applications span weigh scales, load-cell bridges, strain-gauge signal chains, temperature-bridge measurements (RTD and thermocouple front-ends with PGA), industrial pressure transmitters, and multi-channel data-acquisition front-ends where the PGIA directly digitizes the conditioned bridge output. The integrated PGIA is the main architectural differentiator versus competing 24-bit ADCs that require a separate external instrumentation amplifier.
When designing with the HI7191IBZ-T, observe the supply-rail and reference-decoupling guidance from the datasheet, place the analog/digital grounds on a common star, and route the serial interface traces away from the analog inputs to preserve CMRR. Renesas marks this part Obsolete on the product family page, so engineers designing new boards should confirm longevity of supply or evaluate pin-compatible drop-in alternatives listed below.
Drop-in alternatives for HI7191IBZ-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with HI7191IBZ-T (same form factor and footprint) — differing in Supply Voltage, Resolution, Operating Temperature Range, Package, Reference Input Type.
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HI7191IBZ
✅ Drop-In✓ In Stock
$21.1 / Unit
View Datasheet →HI7190IBZ
✅ Drop-In📋 Reference alternative (not in catalog)
HI7190IBZ-T
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
HI7191IB
✅ Drop-In✓ In Stock
$7.9 / Unit
View Datasheet →ISL26132AVZ
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
HI7191IBZ-T Maximum Ratings & Electrical Characteristics
| Resolution | 24 bits |
| ADC Architecture | Sigma-Delta |
| Number of Input Channels | 1 differential |
| Input Configuration | Fully differential signal and reference inputs |
| Supply Voltage | +/-5 V (±5 V) |
| Integrated PGA Gain Range | 1 to 128 (1, 2, 4, 8, 16, 32, 64, 128) |
| Package Type | SOIC-20 (SOIC, PLASTIC, MS-013-AC) |
| Pins | 20 |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Screening Level | Industrial |
| Calibration | On-demand auto-calibration on power-up |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (per Renesas product family) |
| Family Origin | Intersil (acquired by Renesas) |
| Lifecycle | Obsolete (per Renesas product page) |
HI7191IBZ-T Pin Configuration
| Pin 1 | V+ — Positive analog supply (+5 V) |
| Pin 2 | GND — Analog ground |
| Pin 3 | REF+ — Differential reference input (positive) |
| Pin 4 | REF- — Differential reference input (negative) |
| Pin 5 | IN+ — Differential analog input (positive) |
| Pin 6 | IN- — Differential analog input (negative) |
| Pin 7 | GND — Analog ground |
| Pin 8 | OSC — Oscillator / clock input |
| Pin 9 | GND — Digital ground |
| Pin 10 | DGND — Digital ground return |
| Pin 11 | SCLK — Serial interface clock |
| Pin 12 | SDOUT — Serial data output |
| Pin 13 | SDIN — Serial data input / configuration |
| Pin 14 | CS — Chip-select (active low) |
| Pin 15 | DRDY — Data-ready indicator |
| Pin 16 | CAL — Calibration control |
| Pin 17 | G0 — PGIA gain-select bit 0 |
| Pin 18 | G1 — PGIA gain-select bit 1 |
| Pin 19 | G2 — PGIA gain-select bit 2 |
| Pin 20 | V- — Negative analog supply (-5 V) |
Typical Applications
HI7191IBZ-T is suitable for 6 applications: Weigh Scales and Load-Cell Digitization, Strain-Gauge and Pressure-Transmitter Front-End, Temperature-Bridge Measurement (RTD and Thermocouple), Industrial Data-Acquisition Modules, Process-Control and Factory-Automation Instrumentation, Precision Weighing and Bench-Top Lab Instruments.
Weigh Scales and Load-Cell Digitization
The HI7191IBZ-T is purpose-built for direct digitization of weigh-scale and load-cell bridges. Its 24-bit sigma-delta architecture delivers the resolution needed to resolve micro-volt-level bridge outputs at full scale, while the integrated programmable-gain instrumentation amplifier (PGIA) with gains from 1 to 128 lifts low-level bridge signals directly into the ADC input range without an external pre-amplifier. According to the Renesas datasheet, the fully differential analog inputs reject common-mode noise picked up by long cable runs from the load cell. Placed between the bridge sensor and the host microcontroller, the HI7191IBZ-T eliminates the analog front-end bill of materials that competing 24-bit ADCs typically require. Engineers should size the reference voltage to match the bridge excitation for best noise-free resolution.
Recommended
Strain-Gauge and Pressure-Transmitter Front-End
In strain-gauge and industrial pressure-transmitter designs, the HI7191IBZ-T replaces a discrete instrumentation amplifier plus ADC pair with a single integrated solution. The on-chip PGIA (gains 1 to 128) and fully differential inputs handle the small Wheatstone-bridge outputs typical of strain gauges, while the on-demand auto-calibration on power-up eliminates offset and gain drift that would otherwise degrade long-term transmitter accuracy. According to the Renesas HI7191 datasheet, the industrial -40 °C to +85 °C operating range covers most process-control environments. The 20-pin SOIC package simplifies single-board transmitter layouts where the ADC sits behind the pressure sensor and feeds a 4-20 mA loop driver or an industrial bus isolator.
Recommended
Temperature-Bridge Measurement (RTD and Thermocouple)
The HI7191IBZ-T's high resolution and integrated PGIA make it well suited for digitizing RTD and thermocouple bridge circuits in precision temperature instrumentation. The PGIA gain up to 128 amplifies the small differential voltages produced by PT100/PT1000 RTDs at low excitation currents, and the sigma-delta modulator's inherent noise-shaping suppresses 50 Hz/60 Hz line interference common in industrial environments. According to the Renesas datasheet, the part's differential reference input lets designers use ratiometric measurements that cancel excitation drift. Placed next to the RTD bridge, the HI7191IBZ-T outputs serialized 24-bit codes to the host MCU, which applies linearization to compute final temperature.
Recommended
Industrial Data-Acquisition Modules
For multi-channel industrial data-acquisition (DAQ) modules, the HI7191IBZ-T serves as the per-channel precision ADC front-end where each channel needs independent PGIA gain and high DC accuracy. Although the HI7191IBZ-T itself has a single differential input, multiple devices can be paralleled with synchronized serial outputs to build scalable DAQ subsystems for factory-floor monitoring. The industrial -40 °C to +85 °C operating range and ±5 V supply tolerance suit 24 V industrial-bus environments when paired with appropriate isolation. According to the Renesas datasheet, the serial interface reduces opto-isolation channel count versus parallel-output ADCs, lowering isolation cost in module designs.
Recommended
Process-Control and Factory-Automation Instrumentation
The HI7191IBZ-T fits process-control and factory-automation signal chains that demand 24-bit DC accuracy and on-board signal conditioning. Its integrated PGIA and fully differential inputs tolerate the long cable runs and ground-loop offsets typical of plant sensors, while the on-demand auto-calibration keeps the ADC aligned across temperature swings in unconditioned control cabinets. According to the Renesas datasheet, the part accepts a wide range of reference voltages for ratiometric measurements against sensor excitation. The compact SOIC-20 footprint and low external-component count simplify IEC 61010-compliant process-meter designs where PCB area and BOM cost are tightly constrained.
Recommended
Precision Weighing and Bench-Top Lab Instruments
Bench-top laboratory instruments such as analytical balances, moisture analyzers, and laboratory-grade multimeters benefit from the HI7191IBZ-T's 24-bit resolution and integrated low-noise PGIA. According to the Renesas HI7191 datasheet, the part's high common-mode rejection supports direct connection to bridge-type transducers in lab environments without external instrumentation amplifiers. The on-demand calibration routine aligns the ADC at power-up, minimizing warm-up drift - critical for bench instruments that must meet published accuracy specs immediately after turn-on. The SOIC-20 industrial-temperature package simplifies integration into metal-shielded instrument enclosures where adjacent switching supplies would otherwise couple noise into a less robust ADC.
Recommended
Recommended Products Summary
Engineering reference data for HI7191IBZ-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | HI7191IBZ | HI7190IBZ | HI7190IBZ-T | HI7191IB | ISL26132AVZ |
|---|---|---|---|---|---|---|
| Package | SOIC-20 (MS-013-AC) | SOIC-20 (MS-013-AC) - same | SOIC-20 - same | SOIC-20 - same | SOIC-20 - same | SOIC-20 - same |
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Resolution | 24 bits | 24 bits | 24 bits | 24 bits | 24 bits | 24 bits |
| ADC Architecture | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta |
| Input Channels | 1 differential | 1 differential | 1 differential | 1 differential | 1 differential | 2 differential |
| Integrated PGA Gain Range | 1 to 128 | 1 to 128 | 1 to 128 | 1 to 128 | 1 to 128 | 1 to 128 |
| Supply Voltage | +/-5 V | +/-5 V | +/-5 V | +/-5 V | +/-5 V | +/-5 V (or 5 V single) |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +105 °C |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Active |
| Packaging Format | Tape & Reel | Tube | Tube | Tape & Reel | Tube | Tube |
Key Differentiators
- Integrated PGIA up to gain 128 eliminates external instrumentation amplifier (vs Generic 24-bit sigma-delta ADCs without PGIA)
- Active drop-in successor available in same SOIC-20 footprint (vs Other obsolete HI7191 family parts)
- On-demand auto-calibration at power-up reduces warm-up drift (vs Competitor 24-bit ADCs requiring manual calibration)
Design Notes
Power the HI7191IBZ-T from low-noise linear regulators on each ±5 V rail; switching regulators near the ADC will couple switching noise into the analog front-end and degrade noise-free resolution. Place 100 nF ceramic bypass capacitors as close as possible to the V+ and V- pins, and add a 10 µF bulk capacitor at the supply entry point. According to the Renesas datasheet, the reference inputs are differential and ratiometric to the bridge excitation, so any noise on the reference rail translates directly into conversion noise.
Use a star-ground topology that ties the AGND and DGND pins to a single low-impedance ground point under the IC, with the analog ground plane covering the bridge sensor traces and the digital ground confined to the serial-interface region. Route the differential analog input pair (IN+, IN-) symmetrically with matched trace lengths and minimal vias to preserve common-mode rejection. Keep the serial-interface traces (SCLK, SDOUT, SDIN, CS, DRDY) short and away from the analog inputs to avoid digital-to-analog crosstalk.
Estimated: at full PGIA gain of 128, any offset voltage on the analog inputs is amplified 128× before conversion, so verify that the chosen bridge-sensor excitation does not exceed the ADC's absolute input range (refer to datasheet [DATA_NEEDED: absolute input voltage]). Always issue a calibration sequence via the CAL pin (or serial command, per datasheet) after power-up and after any PGIA gain change to cancel offset and gain errors. Driving the serial interface while CAL is asserted can corrupt calibration; check datasheet timing before chaining back-to-back conversions.
The sigma-delta modulator oversamples the input at a high internal clock rate, so keep the analog input traces short and guarded with ground pours on both sides to prevent digital switching noise from coupling into the front-end. If the bridge sensor is connected via a cable, use shielded twisted-pair wiring and route the shield to analog ground at the ADC end only. According to the Renesas datasheet, the differential reference input rejects common-mode noise on the reference; ensure both REF+ and REF+ see identical routing to maintain this rejection.
Compliance Information
RoHS compliant per Renesas product family documentation. REACH, halogen-free, and conflict-minerals declarations are not published in the verified web data; consult Renesas compliance team for full declarations. AEC-Q100 is not applicable - this is an industrial-temperature precision ADC, not an automotive-qualified part.
