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Analog Devices Inc. REF191ES
- Part No.:
- REF191ES
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
REF191ES.pdf
- Description:
- IC VREF SERIES 0.1% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,465
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Product details
Overview
REF191ES from Analog Devices is a precision micropower low-dropout voltage reference IC delivering 2.048 V output with ±2 mV initial accuracy, 5 ppm/°C max temperature coefficient, and 45 μA max supply current-designed for high-accuracy ADC/DAC biasing in portable instrumentation and solar-powered sensor nodes.
For engineers reviewing the REF191ES datasheet, REF191ES pinout, REF191ES application, or REF191ES equivalent, key selection criteria include dropout voltage (≤1.55 V at 30 mA), sleep-mode current (≤15 μA), load regulation (≤15 ppm/mA), and extended industrial temperature operation (−40°C to +125°C).
Technical Context
The REF191ES uses a patented curvature-corrected band gap core with laser-trimmed thin-film resistors to achieve stable 2.048 V output across temperature. Its low-dropout architecture enables operation with only 100 mV headroom above output voltage, supporting battery-supplied systems down to ~2.15 V input.
Sleep mode is controlled via TTL/CMOS-compatible SLEEP pin (VH ≥ 2.4 V, VL ≤ 0.8 V), disabling output and reducing quiescent current to ≤15 μA. Output short-circuit protection and 1 μF mandatory output bypass capacitor ensure robustness in embedded signal chains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Output Voltage | 2.048 V - precisely matches 12-bit full-scale LSB step for 3.3 V ADCs and simplifies ratiometric sensor scaling. |
| Initial Accuracy | ±2 mV maximum - enables <1 LSB error in 12-bit systems without calibration. |
| Temp. Coefficient | 5 ppm/°C max - contributes ≤0.5 mV drift over −40°C to +85°C, critical for uncalibrated field instruments. |
| Supply Current | 45 μA max - supports multi-year battery life in wireless sensor nodes drawing <100 μA average. |
| Dropout Voltage | 1.55 V at 30 mA - allows operation from single Li-ion (3.0–3.6 V) or two alkaline cells (2.4–3.2 V). |
| Load Regulation | 15 ppm/mA max - ensures <0.03 mV shift per mA load change, essential for dynamic current-sense references. |
| Noise (0.1–10 Hz) | 20 μV p-p - minimizes quantization uncertainty in high-resolution (<16-bit) data acquisition. |
Pinout & Package
REF191ES is housed in an 8-lead SOIC_N (SOIC-8) package (S suffix), with exposed pad not electrically connected. Pin 1 and Pin 5 are factory test points (TP) and must remain unconnected in circuit.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (TP) | Factory Zener trim point | No user connection; internal laser trimming node-floating connection prevents accuracy degradation. |
| 2 (VS) | Positive supply input | Accepts 2.15 V to 15 V; dropout as low as 100 mV enables ultra-low-voltage operation. |
| 3 (SLEEP) | Digital enable control | TTL/CMOS-compatible input; drives output to high-Z and cuts supply current to ≤15 μA when low. |
| 4 (GND) | Analog ground reference | Must be star-connected to system AGND; separates reference return from power return paths. |
| 5 (TP) | Factory Zener trim point | No user connection; floating state preserves factory-calibrated output voltage. |
| 6 (NC) | No connect | Internally unused; leave unconnected-no routing or grounding permitted. |
| 7 (NC) | No connect | Internally unused; leave unconnected-no routing or grounding permitted. |
| 8 (OUTPUT) | Precision voltage source | Delivers 2.048 V ±2 mV; requires 1 μF ceramic capacitor to GND for stability and noise reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Curvature-corrected band gap | Reduces parabolic temperature drift, enabling 5 ppm/°C max TC over −40°C to +85°C without external compensation. |
| Low-dropout operation | Supports 2.15 V minimum input for 2.048 V output-enables direct use with single-cell LiFePO₄ or dual alkaline supplies. |
| Sleep mode control | Reduces supply current from 45 μA to ≤15 μA while maintaining fast wake-up (<10 μs), ideal for duty-cycled sensor nodes. |
| Laser-trimmed thin-film resistors | Ensures ±2 mV initial accuracy and <1.2 mV long-term drift after 1000 hours at 125°C-critical for maintenance-free field devices. |
| Short-circuit protected output | Withstands indefinite output-to-ground faults without damage or parameter shift-eliminates need for external current limiting. |
Applications
| Portable Instrumentation | ADC/DAC Reference |
|---|---|
Use Scenario: Handheld multimeter with 12-bit SAR ADC and coin-cell battery supply. IC Role / Device Role / Timing Role: Primary voltage reference for ADC conversion and internal DAC calibration. Use Value: 2.048 V output enables exact 1 mV/LSB scaling; 45 μA supply current extends battery life beyond 2 years. |
Use Scenario: Industrial PLC analog input module with simultaneous sampling of 8 channels. IC Role / Device Role / Timing Role: Shared reference for multiplexed 16-bit sigma-delta ADC front-end. Use Value: 5 ppm/°C TC and 20 μV p-p noise prevent channel-to-channel gain mismatch and thermal drift errors. |
| Smart Sensor Nodes | Solar-Powered Monitoring |
Use Scenario: Wireless temperature/humidity sensor using LoRaWAN and CR2032 battery. IC Role / Device Role / Timing Role: Bias reference for precision RTD and capacitive humidity sensing circuits. Use Value: Sleep mode reduces reference current to ≤15 μA during 99% idle time, enabling >5-year deployment. |
Use Scenario: Remote environmental station powered by 2.5 W solar panel and supercapacitor buffer. IC Role / Device Role / Timing Role: Stable reference for ADC measuring photodiode current and battery voltage. Use Value: 1.55 V dropout allows operation during low-light periods when panel output drops to ~2.6 V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADR3412ARJZ-R7 | Fixed 1.200 V output; 3 ppm/°C TC; 12 μA supply current; no sleep mode. | Better TC and lower IQ, but incompatible output voltage for 2.048 V–based ADC designs. | Select only if system redesign permits 1.2 V reference and eliminates need for sleep control. |
| MAX6126AASA20+T | 2.048 V output; 3 ppm/°C TC; 120 μA supply current; no sleep pin; SO-8 package. | Higher IQ negates battery-life benefit; lacks digital disable, limiting power cycling capability. | Choose when absolute lowest TC is prioritized over micropower operation and sleep functionality. |
Compared with ADR3412ARJZ-R7 and MAX6126AASA20+T, REF191ES uniquely balances 2.048 V output, 5 ppm/°C TC, 45 μA supply current, and active sleep control-making it the only option that preserves ADC scaling, extends battery life, and enables firmware-controlled power gating without external logic.
Availability
REF191ES is available at Aetrix Electronics and suitable for portable instrumentation, precision ADC/DAC reference design, and solar-powered monitoring systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for REF191ES includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.
The REF19x series was engineered for micropower, low-dropout precision referencing in space-constrained, battery-operated, and wide-temperature industrial systems-emphasizing accuracy retention under thermal stress and minimal supply overhead.
FAQ
What is the nominal output voltage of the REF191ES?
The REF191ES provides a nominal output voltage of 2.048 V, optimized for direct compatibility with 12-bit analog-to-digital converters where 2.048 V corresponds to exactly 1 mV per LSB. This value is laser-trimmed and specified with ±2 mV initial accuracy across the E-grade version at 25°C.
Does the REF191ES require an external output capacitor?
Yes, the REF191ES requires a minimum 1 μF ceramic capacitor connected between the OUTPUT pin and GND for stability and noise reduction. This capacitor is mandatory per the datasheet and suppresses low-frequency noise (0.1–10 Hz) to 20 μV p-p while ensuring loop stability under varying load conditions.
How does the SLEEP pin function on the REF191ES?
The SLEEP pin on the REF191ES is a TTL/CMOS-compatible digital input that disables the output stage and reduces supply current to ≤15 μA when pulled low (≤0.8 V). When high (≥2.4 V), normal operation resumes with full 2.048 V output and ≤45 μA supply current-enabling firmware-controlled power gating in energy-sensitive applications.
What is the maximum dropout voltage for the REF191ES at full load?
The REF191ES exhibits a maximum dropout voltage of 1.55 V at 30 mA load current, measured at VS = 3.6 V. This low-dropout performance allows operation from supply rails as low as 2.15 V (2.048 V + 100 mV headroom), making it suitable for single-cell Li-ion and dual-alkaline battery systems.
Is the REF191ES rated for automotive temperature ranges?
Yes, the REF191ES is characterized and specified over −40°C to +125°C for all electrical grades, with typical performance validated across this extended range. While not AEC-Q200 qualified, its tested behavior supports under-hood and industrial control applications where ambient temperatures exceed +85°C.
REF191ES Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- REF19
- Packaging:
- Tube
- Product Status:
- Obsolete
- Reference Type:
- Series
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.048V
- Voltage - Output (Max):
- -
- Current - Output:
- 30 mA
- Tolerance:
- ±0.1%
- Temperature Coefficient:
- 5ppm/°C
- Noise - 0.1Hz to 10Hz:
- 20µVp-p
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- 3V ~ 15V
- Current - Supply:
- 45µA
- Current - Cathode:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
REF191ES FAQ
1.How can I place an order for REF191ES through Aetrix?
Please submit a Request for Quotation (RFQ) for REF191ES on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for REF191ES reliable?
The price and inventory of REF191ES are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for REF191ES is usually 5 days.
3.What payment methods are accepted for REF191ES?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for REF191ES transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for REF191ES?
REF191ES orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your REF191ES order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for REF191ES?
For technical support, including REF191ES datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your REF191ES requirements.
6.How does Aetrix verify that REF191ES is sourced from the original manufacturer or authorized distributors?
All REF191ES products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that REF191ES meets industry standards.
7.What is the process for return or replacement of REF191ES?
All REF191ES units undergo pre-shipment inspection (PSI). If there is an issue with REF191ES, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The REF191ES part is unused and in its original packaging.
Return procedure for REF191ES:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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