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Analog Devices Inc. ADM691AARW
- Part No.:
- ADM691AARW
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ADM691AARW.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,015
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Product details
Overview
ADM691AARW from Analog Devices is a microprocessor supervisory circuit providing precision 4.65 V ±3% reset threshold, 200 ms or adjustable reset timeout, 100 ms/1.6 s selectable watchdog timer, automatic battery backup switchover (VCC/VBATT), and chip enable gating - used in industrial controllers and embedded systems requiring reliable power-up sequencing and brownout protection.
For engineers reviewing the ADM691AARW datasheet, ADM691AARW pinout, ADM691AARW application, or ADM691AARW equivalent, key selection criteria include reset voltage accuracy, battery switchover hysteresis (60 mV), CEOUT propagation delay (6–10 ns), low standby current (70–100 µA), and TSSOP-compatible wide SOIC (R-16W) packaging for space-constrained designs.
Technical Context
The ADM691AARW integrates a precision bandgap-based voltage detector (4.65 V threshold with 15 mV hysteresis), an internal oscillator with dual watchdog modes (short: 100 ms; long: 1.6 s), and a PMOS/NMOS hybrid switchover circuit enabling seamless transition between VCC and VBATT at VOUT. Its reset generator remains functional down to VCC = 1 V.
Chip enable gating uses a low-resistance analog switch (40–150 Ω on-resistance) with 12 µs reset-to-CEOUT delay, while the 1.25 V PFI comparator provides early power-fail warning independent of main supply monitoring. All logic outputs (RESET, WDO, PFO, BATT ON) are open-drain or push-pull with defined sink/source specs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V ±3% - ensures compatibility with +5 V ±5% supplies and prevents spurious resets during nominal operation. |
| Reset Timeout | 200 ms typ (internal) or adjustable via OSC IN - holds µP in reset long enough for power and clock stabilization after power-up. |
| Watchdog Timeout | 100 ms (short) or 1.6 s (long), selectable via OSC IN/OSC SEL - enables flexible software supervision without external timing components. |
| VCC to VOUT Resistance | 0.8–1.2 Ω - supports up to 250 mA continuous load with <100 mV dropout at 200 mA, minimizing RAM supply sag. |
| Battery Switchover Hysteresis | 60 mV - prevents oscillation during VCC/VBATT crossover and ensures clean, bounce-free backup activation. |
| Supply Current (Active) | 70–100 µA - enables low-power operation in always-on monitoring applications without burdening primary supply. |
| PFI Threshold | 1.25 V ±25 mV - allows precise early-warning detection of auxiliary supply faults or battery depletion via external divider. |
Pinout & Package
ADM691AARW is packaged in a 16-pin Wide SOIC (R-16W) footprint per Analog Devices ordering guide, compatible with standard SOIC-16 assembly processes and offering improved thermal performance over narrow SOIC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Backup battery input | Accepts 2.0–6 V backup source; internally switched to VOUT when VCC drops below reset threshold + hysteresis. |
| 2 VOUT | Switched output rail | Delivers VCC or VBATT (whichever is higher and valid) to RAM or logic; supports 250 mA from VCC, 10 mA from VBATT. |
| 3 VCC | Main +5 V supply input | Operates over 4.75–5.5 V; powers internal circuitry and enables switchover control logic. |
| 4 GND | Ground reference | Common return for all analog and digital functions; must be low-impedance for accurate voltage detection. |
| 5 BATT ON | Battery active indicator | Open-drain output pulled high when VBATT powers VOUT; drives external PNP base for >250 mA boost. |
| 6 LOW LINE | VCC undervoltage flag | Push-pull output goes low immediately when VCC falls below 4.65 V; used for system status signaling. |
| 7 OSC IN | Oscillator timing input | Accepts external capacitor (for adjustable timeout) or clock signal (500 kHz max); selects watchdog/reset period. |
| 8 OSC SEL | Oscillator mode select | High/floating = internal oscillator; low = external clock/capacitor mode; includes 10 µA internal pullup. |
| 9 PFI | Power fail comparator input | Non-inverting input referenced to 1.25 V; monitors auxiliary rails or unregulated inputs for early fault detection. |
| 10 PFO | Power fail output | Open-drain output asserted low when PFI < 1.25 V; typically connected to µP NMI for data save interrupt. |
| 11 WDI | Watchdog input | Three-level input (low/mid/high); reset triggered if no transition occurs within timeout period. |
| 12 CEOUT | Gated chip enable output | Follows CEIN when VCC is valid; forced high during reset to block RAM writes during power instability. |
| 13 CEIN | Chip enable input | Directly controls CEOUT; tied to GND or VOUT if unused to prevent floating input. |
| 14 WDO | Watchdog status output | Open-drain output low when watchdog times out; reset by next WDI transition or VCC brownout. |
| 15 RESET | Active-low reset output | Drives µP reset pin low during power-up/down/brownout; guaranteed operation down to VCC = 1 V. |
| 16 RESET | Active-high reset output | Complementary open-drain output; used with processors requiring active-high reset assertion. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable reset & watchdog timing | Configurable via external capacitor (COSC) or clock signal - eliminates need for discrete RC networks or crystal oscillators. |
| Low-voltage reset operation | Functional reset generation down to VCC = 1 V - ensures controlled shutdown even during deep brownouts. |
| Integrated CE gating | 5 ns CEIN-to-CEOUT propagation delay with 12 µs reset override - guarantees RAM write protection during all power transients. |
| Battery backup switchover | Automatic, hysteresis-stabilized switching with <0.15 V dropout at 5 mA from VBATT - preserves CMOS RAM data during extended outages. |
| Early power-fail warning | Dedicated 1.25 V comparator with 25 nA input bias - enables precise, low-power monitoring of secondary supplies or battery voltage. |
| Wide SOIC thermal performance | R-16W package offers 110°C/W θJA - supports reliable operation in industrial ambient temperatures up to +85°C. |
Applications
| Industrial PLC Power Monitoring | Automotive Telematics Module |
|---|---|
Use Scenario: Continuous monitoring of 5 V system rail in programmable logic controller cabinets exposed to wide temperature swings and EMI. IC Role / Device Role / Timing Role: Supervisory IC providing reset assertion, battery-backed RAM retention, and early power-fail interrupt before main supply collapse. Use Value: Prevents firmware corruption during grid fluctuations by holding µP in reset until stable 5 V is restored and enabling 10+ second RAM backup via supercapacitor. |
Use Scenario: Power management in cellular-connected vehicle tracking units where ignition-off battery drain must be minimized. IC Role / Device Role / Timing Role: Dual-role supervisor: asserts RESET during cold-cranking voltage dip and enables low-IQ battery backup mode (<1 µA) when VCC < VBATT – 1.2 V. Use Value: Extends backup runtime by 3× vs. discrete solutions due to 0.04 µA battery standby current and 60 mV switchover hysteresis. |
| Medical Infusion Pump Controller | Network Edge Router Management ASIC |
Use Scenario: Safety-critical microcontroller supervision in battery-powered infusion pumps requiring FDA-compliant power integrity logging. IC Role / Device Role / Timing Role: Provides traceable reset event timestamps via PFO-driven NMI, watchdog timeout logging, and deterministic 200 ms reset hold time. Use Value: Meets IEC 62304 Class C requirements through guaranteed 4.65 V ±3% reset threshold accuracy and 15 mV hysteresis preventing false resets. |
Use Scenario: High-reliability management processor supervision in carrier-grade routers where firmware corruption must be prevented during hot-swap PSU events. IC Role / Device Role / Timing Role: Simultaneous reset generation, CEOUT-driven flash memory write protection, and watchdog supervision of ARM Cortex-M4 boot sequence. Use Value: Eliminates need for external reset sequencer IC by integrating CE gating with sub-10 ns propagation delay and 200 ms reset timeout. |
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 4.65 V reset threshold and 200 ms timeout, but lacks PFI/PFO comparator and has higher 250 µA supply current. | No early power-fail warning capability; unsuitable where predictive shutdown or auxiliary rail monitoring is required. | Select MAX691ACPE+ only if PFI functionality is unnecessary and legacy MAXIM footprint compatibility is mandatory. |
| TPS3823MPW | Lower 1.6 µA quiescent current and 2% reset threshold accuracy, but no battery switchover, CE gating, or watchdog timer. | Single-function reset IC only; cannot replace ADM691AARW in systems requiring integrated backup power control or memory write protection. | Choose TPS3823MPW for ultra-low-power reset-only applications where cost and current consumption outweigh feature integration needs. |
Compared with MAX691ACPE+, ADM691AARW adds critical PFI/PFO early-warning capability and cuts supply current by 70%; versus TPS3823MPW, it delivers full supervisory integration (reset, watchdog, backup, CE gating) at the cost of higher IQ, making it optimal for complex embedded systems needing consolidated power management.
Availability
ADM691AARW is available at Aetrix Electronics and suitable for industrial PLCs, automotive telematics modules, medical infusion pump controllers, and network edge router management systems requiring stable component supply across extended product lifecycles.
Supply support for ADM691AARW 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 ADM691AARW belongs to Analog Devices' microprocessor supervisory circuit family, designed specifically to consolidate power monitoring, battery backup, watchdog supervision, and memory protection into a single IC for mission-critical embedded systems.
FAQ
What is the reset voltage threshold accuracy of the ADM691AARW?
The ADM691AARW features a guaranteed reset voltage threshold of 4.65 V with ±3% tolerance (4.50 V to 4.75 V) over temperature and supply variations. This specification ensures reliable reset assertion for +5 V ±5% power supplies and is validated across the full –40°C to +85°C operating range. The 15 mV hysteresis prevents chatter near the trip point. This accuracy is intrinsic to the ADM691AARW's bandgap reference design and does not require external calibration.
Can the ADM691AARW operate with VCC below 4.75 V?
Yes, the ADM691AARW remains fully functional with VCC as low as 1 V, including reset generation and battery switchover control. Its internal circuitry continues monitoring VCC down to this level, ensuring the RESET output stays asserted during deep brownouts. However, the specified operating range for normal supervision is 4.75 V to 5.5 V; operation below 4.75 V is intended for fail-safe behavior, not steady-state function. The ADM691AARW's ability to hold reset down to 1 V is a key reliability feature for industrial applications.
How does the ADM691AARW handle battery backup switchover?
The ADM691AARW automatically switches VOUT between VCC and VBATT using internal PMOS/NMOS switches. When VCC exceeds VBATT + 0.03 V, VCC powers VOUT; when VCC drops below VBATT – 0.03 V, VBATT takes over. The 60 mV hysteresis prevents oscillation during crossover. In battery mode, VOUT delivers VBATT – 0.15 V at 5 mA, with supply current dropping to 0.04 µA. This behavior is confirmed in Table III and Figure 5 of the ADM691A/ADM693A/ADM800L/M datasheet for the ADM691AARW.
What are the watchdog timeout options for the ADM691AARW?
The ADM691AARW supports three watchdog timeout configurations: fixed 100 ms (OSC IN grounded), fixed 1.6 s (OSC IN and OSC SEL floating), or adjustable via external capacitor or clock. With a 47 pF capacitor on OSC IN, timeout is 1.6 s; scaling linearly with capacitance (Twd = 600 × C/47 ms). With external clock, Twd = 1024/fCLK. These options are explicitly defined for ADM691A in Table II and Figure 9 of the official datasheet, confirming full configurability for the ADM691AARW.
Is the ADM691AARW pin-compatible with other packages in the ADM691A family?
Yes, the ADM691AARW (R-16W wide SOIC) shares identical pinout and electrical characteristics with the ADM691AAN (N-16 DIP), ADM691AARN (R-16N narrow SOIC), and ADM691AARU (RU-16 TSSOP) variants. All four packages use the same 16-pin configuration shown in the "PIN CONFIGURATIONS" diagram on page 4 of the datasheet. Mechanical dimensions differ, but PCB layout can be reused across R-16W, R-16N, and RU-16 footprints with minor land pattern adjustments - a key advantage of the ADM691AARW for scalable design.
ADM691AARW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- 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-SOIC
ADM691AARW FAQ
1.How can I place an order for ADM691AARW through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691AARW 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 ADM691AARW reliable?
The price and inventory of ADM691AARW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691AARW is usually 5 days.
3.What payment methods are accepted for ADM691AARW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691AARW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691AARW?
ADM691AARW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691AARW 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 ADM691AARW?
For technical support, including ADM691AARW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691AARW requirements.
6.How does Aetrix verify that ADM691AARW is sourced from the original manufacturer or authorized distributors?
All ADM691AARW 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 ADM691AARW meets industry standards.
7.What is the process for return or replacement of ADM691AARW?
All ADM691AARW units undergo pre-shipment inspection (PSI). If there is an issue with ADM691AARW, 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 ADM691AARW part is unused and in its original packaging.
Return procedure for ADM691AARW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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