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Analog Devices Inc. ADM691AARU-REEL
- Part No.:
- ADM691AARU-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
ADM691AARU-REEL.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,323
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Product details
Overview
ADM691AARU-REEL from Analog Devices is a microprocessor supervisory circuit integrating power-on reset, battery backup switchover, watchdog timer, chip enable gating, and power-fail detection in a single 16-pin TSSOP package. It provides 4.65 V ±3% reset threshold, 200 ms or adjustable reset timeout, 1.6 s/100 ms selectable watchdog timeout, automatic VCC/VBATT switching to VOUT (250 mA max), and 1.25 V PFI comparator. It is used in industrial controllers and embedded systems requiring reliable power monitoring and RAM write protection.
For engineers reviewing the ADM691AARU-REEL datasheet, ADM691AARU-REEL pinout, ADM691AARU-REEL application, or ADM691AARU-REEL equivalent, key selection criteria include reset voltage accuracy (±3%), battery switchover hysteresis (60 mV), CEOUT propagation delay (10 ns typ), WDI input threshold compatibility (0.75×VCC), and TSSOP-16 thermal performance (θJA = 158°C/W).
Technical Context
The ADM691AARU-REEL implements a dual-path power management architecture: a precision bandgap-based 4.65 V reset detector with 15 mV hysteresis and an independent 1.25 V PFI comparator for early power-fail warning. Its internal oscillator supports fixed (200 ms / 1.6 s) or capacitor-adjustable timing via OSC IN/OSC SEL pins.
It features bidirectional battery switchover using PMOS (VCC→VOUT, RON ≈ 0.75 Ω) and NMOS (VBATT→VOUT, RON ≈ 7 Ω) switches, with BATT ON output enabling external PNP transistor drive. CEIN-to-CEOUT gating operates with 6–10 ns propagation delay and 40–150 Ω on-resistance, ensuring robust RAM write protection during brownouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V ±3% - ensures reliable reset assertion for +5 V ±5% supplies without false triggering. |
| Reset Timeout | 200 ms typ (adjustable) - holds µP in reset long enough for power and clock stabilization post-power-up. |
| Watchdog Timeout | 1.6 s long / 100 ms short period - configurable via OSC SEL/OSC IN to match firmware execution cycles. |
| VCC→VOUT Resistance | 0.8–1.2 Ω at 25 mA - enables low-dropout supply to CMOS RAM with <50 mV dropout at rated load. |
| Battery Standby Current | 0.04–1 µA - extends backup battery life for multi-year memory retention in low-power systems. |
| PFI Threshold | 1.25 V ±25 mV - allows precise early-warning detection of falling VCC via external resistor divider. |
| CEIN Leakage | ±0.005 µA - prevents unintended CEOUT activation in high-impedance microcontroller interface designs. |
Pinout & Package
ADM691AARU-REEL is housed in a 16-lead Thin Shrink Small Outline Package (TSSOP, RU-16), 4.4 mm × 5.0 mm body, 0.65 mm pitch, with exposed pad for thermal enhancement. Pin 1 marked by dot; pin numbering counterclockwise from top-left corner.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VBATT) | Backup battery input | Connects to Li-ion, supercapacitor, or NiMH; enables seamless switchover when VCC drops below reset threshold. |
| 2 (VOUT) | Switched output rail | Delivers VCC or VBATT (whichever is higher and valid) to RAM; supports 250 mA continuous load. |
| 5 (BATT ON) | Battery status indicator & base driver | Drives external PNP transistor base to boost VOUT current beyond 250 mA; logic-high when VBATT powers VOUT. |
| 7 (OSC IN) | Oscillator timing input | Accepts external clock (≤250 kHz) or capacitor (47 pF typical) to adjust reset/watchdog timeouts per Table II. |
| 9 (PFI) | Power fail sense input | Non-inverting input to 1.25 V comparator; monitors divided-down VCC for early shutdown warning before reset triggers. |
| 11 (WDI) | Watchdog input | Three-level input (low/mid/high); resets watchdog on each transition; floating disables watchdog function. |
| 12 (CEOUT) | Gated chip enable output | Replicates CEIN when VCC > reset threshold; forced high during brownout to block RAM writes. |
| 15/16 (RESET/RESET) | Complementary reset outputs | Active-low open-drain RESET and active-high totem-pole RESET support diverse µP reset polarity requirements. |
Key Features
| Feature | Design Value |
|---|---|
| Low-power battery backup mode | 0.04 µA typical supply current enables >10-year coin-cell operation in always-on memory backup. |
| Adjustable watchdog timeout | Configurable from 100 ms to 2.4 s via external capacitor or clock - matches real-time firmware loop timing. |
| Integrated CE gating | 5 ns propagation delay and 40 Ω on-resistance ensure deterministic RAM write blocking during power transients. |
| 1.25 V precision PFI reference | ±25 mV tolerance over temperature enables accurate power-fail prediction with minimal external components. |
| TSSOP-16 thermal performance | 158°C/W junction-to-ambient thermal resistance supports operation up to +85°C ambient in dense PCB layouts. |
Applications
| Industrial PLC Controller | Automotive Body Control Module |
|---|---|
Use Scenario: Power monitoring and nonvolatile RAM protection in programmable logic controllers operating in factory environments with wide temperature swings and EMI. IC Role / Device Role / Timing Role: Supervisory IC providing reset generation, battery-backed RAM switchover, and watchdog supervision of safety-critical firmware. Use Value: Prevents data corruption during brownouts via CEOUT-driven write blocking and ensures deterministic recovery after power interruption with 200 ms reset hold time. |
Use Scenario: Backup power management and fault detection in automotive door modules with CAN communication and EEPROM storage. IC Role / Device Role / Timing Role: Dual-role supervisor: maintains SRAM state during ignition-off battery drain and detects pre-brownout conditions via PFI/PFO. Use Value: Enables safe EEPROM save operations before main 12 V rail collapse, using PFO-triggered NMI interrupt with ≥25 µs response latency. |
| Medical Infusion Pump | Smart Energy Meter |
Use Scenario: Critical power integrity assurance in Class II medical devices where RAM data loss could compromise dosage accuracy or alarm functionality. IC Role / Device Role / Timing Role: Fault-tolerant supervisor with redundant reset outputs (RESET/RESET) and battery switchover supporting >5-year backup runtime. Use Value: Guarantees RAM retention during AC mains failure via ultra-low 0.04 µA battery standby current and 7 Ω VBATT→VOUT switch. |
Use Scenario: Tamper-resistant data logging in utility meters requiring secure metering data preservation across grid instability events. IC Role / Device Role / Timing Role: Power supervisor with PFI-based early warning and watchdog-enforced firmware health check for metrology processor. Use Value: Delivers 1.6 s watchdog timeout to validate metering algorithm execution while allowing 100 ms short timeout for fast-recovery calibration routines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACPE+ | Same pinout, 4.65 V reset threshold, but higher 10 µA quiescent current and no TSSOP option. | Lacks integrated CE gating and has slower 25 µs PFI→PFO delay vs. 25–60 µs for ADM691AARU-REEL. | Select MAX691ACPE+ only if DIP-16 packaging is required and CE gating is implemented externally. |
| TPS3823MPW | Lower 1.5 µA supply current, but fixed 200 ms reset timeout and no battery switchover or watchdog functions. | Supports only basic reset supervision; cannot replace ADM691AARU-REEL in battery-backed RAM or watchdog-dependent systems. | Choose TPS3823MPW only for cost-sensitive, non-backup applications where watchdog and CE gating are unnecessary. |
Compared with MAX691ACPE+, ADM691AARU-REEL delivers 99.996% lower battery standby current and integrated CE gating; versus TPS3823MPW, it adds full battery switchover, adjustable watchdog, and PFI-based predictive power fail detection - essential for mission-critical embedded systems.
Availability
ADM691AARU-REEL is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply with guaranteed long-term availability.
Supply support for ADM691AARU-REEL 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, serving industrial, automotive, communications, and healthcare markets since 1965.
The ADM691AARU-REEL belongs to Analog Devices' microprocessor supervisory product line, designed specifically for robust power monitoring, battery backup, and firmware health verification in safety-critical embedded systems.
FAQ
What is the reset voltage threshold accuracy of the ADM691AARU-REEL?
The ADM691AARU-REEL features a guaranteed reset voltage threshold of 4.65 V with ±3% tolerance over temperature and supply variations. This corresponds to a min/max range of 4.50 V to 4.75 V at +25°C, ensuring compatibility with +5 V ±5% power supplies while preventing spurious resets during nominal operation.
Can the ADM691AARU-REEL support external watchdog timeout adjustment?
Yes, the ADM691AARU-REEL supports external watchdog timeout adjustment via the OSC IN and OSC SEL pins. With OSC SEL grounded, connecting a capacitor (e.g., 47 pF) between OSC IN and GND sets the watchdog timeout to 1.6 s × (C/47 pF), while an external clock input yields Twd = 1024 × (1/fCLK). The ADM691AARU-REEL datasheet Table II details all configuration modes.
How does the ADM691AARU-REEL handle battery switchover during power failure?
The ADM691AARU-REEL automatically switches VOUT from VCC to VBATT when VCC falls below both the reset threshold and VBATT by >60 mV hysteresis. In battery backup mode, VOUT is sourced from VBATT through a 7 Ω NMOS switch, delivering up to 10 mA at 2.0 V input with <150 mV dropout, while drawing only 0.04 µA standby current from the battery.
What is the purpose of the complementary RESET and RESET outputs on the ADM691AARU-REEL?
The ADM691AARU-REEL provides both active-low open-drain RESET and active-high totem-pole RESET outputs to accommodate microprocessors with differing reset polarity requirements. RESET drives low during power faults; RESET mirrors its inverse state and can directly interface with µPs needing active-high reset assertion without external inverters.
Does the ADM691AARU-REEL support chip enable (CE) gating for RAM write protection?
Yes, the ADM691AARU-REEL integrates dedicated CEIN and CEOUT pins that implement hardware-enforced RAM write protection. When VCC remains above the reset threshold, CEOUT replicates CEIN with 6–10 ns delay; when VCC drops below threshold, CEOUT is forced high regardless of CEIN state - preventing erroneous writes during brownouts or power-up sequences.
ADM691AARU-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Open Drain, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
ADM691AARU-REEL FAQ
1.How can I place an order for ADM691AARU-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691AARU-REEL 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 ADM691AARU-REEL reliable?
The price and inventory of ADM691AARU-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691AARU-REEL is usually 5 days.
3.What payment methods are accepted for ADM691AARU-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691AARU-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691AARU-REEL?
ADM691AARU-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691AARU-REEL 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 ADM691AARU-REEL?
For technical support, including ADM691AARU-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691AARU-REEL requirements.
6.How does Aetrix verify that ADM691AARU-REEL is sourced from the original manufacturer or authorized distributors?
All ADM691AARU-REEL 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 ADM691AARU-REEL meets industry standards.
7.What is the process for return or replacement of ADM691AARU-REEL?
All ADM691AARU-REEL units undergo pre-shipment inspection (PSI). If there is an issue with ADM691AARU-REEL, 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 ADM691AARU-REEL part is unused and in its original packaging.
Return procedure for ADM691AARU-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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