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Analog Devices Inc. ADM691AARW-REEL
- Part No.:
- ADM691AARW-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ADM691AARW-REEL.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,555
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Product details
Overview
ADM691AARW-REEL from Analog Devices is a microprocessor supervisory circuit providing power-on reset, battery backup switchover, watchdog timer, CE gating, and power-fail detection in a 16-pin wide SOIC package. It features a 4.65 V ±3% reset threshold, 200 ms or adjustable reset timeout, 1.6 s/100 ms selectable watchdog timeout, and supports VCC down to 1 V during brownout. It is used in industrial controllers and embedded systems requiring reliable power monitoring and RAM write protection.
For engineers reviewing the ADM691AARW-REEL datasheet, ADM691AARW-REEL pinout, ADM691AARW-REEL application, or ADM691AARW-REEL equivalent, key selection criteria include reset voltage accuracy, battery switchover hysteresis (60 mV), VCC-to-VOUT on-resistance (0.8–1.2 Ω), WDI transition-based watchdog enablement, and compatibility with 5 V ±5% supplies.
Technical Context
The ADM691AARW-REEL integrates a precision 4.65 V voltage detector with 15 mV hysteresis, an internal oscillator configurable for 100 ms or 1.6 s watchdog timeout, and dual-mode OSC IN/OSC SEL control for external capacitor or clock-driven timing. Its battery switchover uses PMOS (VCC→VOUT) and NMOS (VBATT→VOUT) switches with validated 60 mV hysteresis and sub-1 µA standby current in backup mode.
CE gating operates with 6–10 ns propagation delay and 40–150 Ω on-resistance; RESET asserts low for ≥200 ms after VCC exceeds threshold and remains functional down to VCC = 1 V. The 1.25 V PFI comparator enables early power-fail warning with 25–60 µs response and ±25 nA input bias.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V ±3% - matches 5 V ±5% supply tolerance; ensures reset assertion before logic corruption. |
| Reset Timeout | 200 ms typ (adjustable) - holds µP in reset long enough for power and clock stabilization. |
| Watchdog Timeout | 100 ms (short) or 1.6 s (long), selectable via OSC IN/SEL - enables flexible software supervision intervals. |
| Battery Switchover Hysteresis | 60 mV - prevents oscillation during VCC/VBATT crossover near threshold. |
| VCC-to-VOUT On-Resistance | 0.8–1.2 Ω @ 25 mA - limits dropout to <30 mV, supporting 250 mA CMOS RAM loads. |
| Supply Current (Normal) | 70–100 µA - enables low-power operation in always-on monitoring applications. |
| PFI Input Threshold | 1.25 V ±25 mV - allows precise early-warning detection of +5 V rail collapse via external divider. |
Pinout & Package
ADM691AARW-REEL is housed in a 16-pin wide SOIC (R-16W) package, 7.5 mm × 10.3 mm, 1.27 mm pitch, RoHS-compliant, with exposed pad not present. Pin functions are electrically validated per Analog Devices datasheet Rev. 0.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Backup battery input | Connects to Li-ion/capacitor; enables seamless switchover when VCC drops below reset threshold. |
| 2 VOUT | Switched output | Delivers VCC or VBATT (whichever higher and valid); powers RAM or low-power logic. |
| 3 VCC | +5 V supply input | Primary power rail; monitored for reset generation and CE gating control. |
| 4 GND | Ground reference | Common return for all analog/digital sections; critical for noise immunity in reset timing. |
| 5 BATT ON | Battery status indicator | Drives external PNP base to boost VOUT current beyond 250 mA limit. |
| 6 LOW LINE | VCC undervoltage flag | Asserts low immediately on VCC drop below 4.65 V; used for fast system alerts. |
| 7 OSC IN | Oscillator timing input | Accepts external clock (≤250 kHz) or capacitor (47 pF → 200 ms reset) for adjustable timing. |
| 8 OSC SEL | Oscillator mode select | High/floating = internal oscillator; low = external clock/capacitor mode. |
| 9 PFI | Power fail sense input | Non-inverting input to 1.25 V comparator; monitors auxiliary rail or divider output. |
| 10 PFO | Power fail warning output | Open-drain NMI trigger; asserts low 1–5 ms before VCC reaches reset threshold. |
| 11 WDI | Watchdog input | Three-level input; reset triggered by missing edge transition within timeout window. |
| 12 CEOUT | Gated chip enable output | Replicates CEIN when VCC valid; forces high during reset to block RAM writes. |
| 13 CEIN | Chip enable input | Directly controls CEOUT; tied to µP CE or memory controller output. |
| 14 WDO | Watchdog status output | Active-low open-drain signal indicating watchdog timeout; resets on next WDI edge. |
| 15 RESET | Active-low reset output | Drives µP reset pin; guaranteed active down to VCC = 1 V during brownout. |
| 16 RESET | Active-high reset output | Inverted complement of RESET; interfaces directly with processors requiring high-active reset. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable reset & watchdog timing | Supports both fixed (200 ms / 1.6 s) and user-configurable timeouts via external capacitor or clock - eliminates need for multiple BOM variants. |
| Sub-1 µA battery backup current | 0.04 µA typ at VBATT = 2.8 V - extends coin-cell life to >10 years in memory-retention applications. |
| VCC-operational down to 1 V | RESET remains functional with VCC as low as 1 V - ensures deterministic shutdown even during deep brownouts. |
| Integrated CE gating with 6 ns delay | Prevents spurious RAM writes during power transients by forcing CEOUT high within 12 µs of reset assertion. |
| 1.25 V precision PFI comparator | ±25 mV threshold tolerance and 25 µs response - enables accurate, noise-immune early power-fail detection. |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
Use Scenario: Power monitoring and nonvolatile memory protection in programmable logic controllers operating in factory environments with noisy 24 V DC supplies. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, battery-backed RAM write blocking, and watchdog supervision of firmware execution loops. Use Value: Prevents corrupted ladder logic execution and data loss during voltage sags; enables 10-year battery-backed SRAM retention without external circuitry. |
Use Scenario: Ensuring safe shutdown and patient data preservation in portable ultrasound devices powered by rechargeable Li-ion batteries. IC Role / Device Role / Timing Role: Dual-role supervisor: manages main 5 V rail integrity and triggers controlled save-to-flash sequence upon PFI-detected power decay. Use Value: Guarantees 200 ms minimum reset hold time for safe firmware state capture; uses PFO/NMI to initiate emergency data dump before VCC collapse. |
| Automotive Body Control Module | Telecom Remote Terminal Unit |
Use Scenario: Monitoring 5 V supply derived from vehicle battery in body electronics modules subject to load-dump and cold-crank conditions. IC Role / Device Role / Timing Role: Reset generator with extended VCC operational range (1–5.5 V) and battery switchover for EEPROM backup during ignition-off periods. Use Value: Maintains secure configuration storage across 12 V battery dips to 6 V; BATT ON output drives external PNP to sustain 300 mA RAM load. |
Use Scenario: Power supervision in outdoor DSLAM line cards exposed to wide temperature swings and unregulated AC-DC conversion. IC Role / Device Role / Timing Role: Primary supervisor for FPGA configuration memory and real-time clock backup, interfacing with isolated power rails. Use Value: Enables reliable field-upgrade capability via WDI-toggled watchdog; PFI divider set to trip at 4.8 V provides 200 ms warning before 5 V rail failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACPE+ | Pin-compatible but 4.65 V reset threshold has ±5% tolerance vs. ADM691AARW-REEL's ±3%; no TSSOP option. | Higher reset threshold drift reduces margin for 5 V ±5% supplies; lacks integrated CE gating propagation control. | Select MAX691ACPE+ only if legacy footprint reuse is mandatory and tighter reset accuracy is not required. |
| TPS3823MPW | Single-supply 5 V supervisor with 4.63 V threshold (±0.5%), but no battery switchover, watchdog, or CE gating functions. | Requires external discrete circuitry for RAM backup and write protection - increases BOM count and board area. | Choose TPS3823MPW only for cost-sensitive, non-battery-backed applications where full ADM691AARW-REEL feature set is unused. |
Compared with MAX691ACPE+, ADM691AARW-REEL delivers tighter reset accuracy and integrated CE gating; compared with TPS3823MPW, it provides complete single-chip supervision including battery switchover and watchdog - eliminating four external components in typical designs.
Availability
ADM691AARW-REEL is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, and automotive body control modules requiring stable component supply, long-lifecycle support, and guaranteed parametric compliance.
Supply support for ADM691AARW-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 ADM691A family was designed specifically for robust microprocessor supervision in harsh environments, integrating reset, watchdog, battery switchover, and memory protection into one IC to reduce system-level complexity and improve reliability.
FAQ
What is the reset voltage threshold accuracy of the ADM691AARW-REEL?
The ADM691AARW-REEL has a guaranteed reset voltage threshold of 4.65 V with ±3% tolerance over temperature (–40°C to +85°C). This corresponds to a min/max range of 4.50 V to 4.75 V, making it suitable for 5 V ±5% power supplies. The specification is validated per Analog Devices datasheet Rev. 0, Table "Reset Voltage Threshold".
Does the ADM691AARW-REEL support battery backup switching with lithium coin cells?
Yes, the ADM691AARW-REEL supports direct connection of lithium coin cells (e.g., CR2032) to VBATT. In battery backup mode, it draws only 0.04 µA typ, enabling >10-year retention life. The device automatically switches VOUT to VBATT when VCC falls below the reset threshold and maintains VOUT regulation down to VBATT = 2.0 V at 5 mA load.
How is the watchdog timeout period configured on the ADM691AARW-REEL?
The ADM691AARW-REEL watchdog timeout is selected using OSC SEL and OSC IN pins. With OSC SEL floating and OSC IN grounded, timeout is fixed at 100 ms (short). With both pins floating, it defaults to 1.6 s (long). For adjustable timing, tie OSC SEL low and connect a capacitor (e.g., 47 pF) from OSC IN to GND - yielding 1.6 s timeout per datasheet Figure 9.
Can the ADM691AARW-REEL drive CMOS RAM chip-enable signals directly?
Yes, the ADM691AARW-REEL provides dedicated CEIN and CEOUT pins for RAM write protection. CEOUT replicates CEIN with 6–10 ns delay when VCC is valid, and forces high during reset - blocking writes to battery-backed RAM. It sources/sinks ±100 µA and operates down to VCC = 0 V in backup mode per Table III.
What is the maximum continuous output current supported by the VOUT pin of the ADM691AARW-REEL?
The VOUT pin of the ADM691AARW-REEL supports up to 250 mA continuous current when powered from VCC, with a typical VCC-to-VOUT on-resistance of 0.75 Ω. At 250 mA, voltage drop is ≤187 mV. For higher currents, the BATT ON output can drive an external PNP transistor as shown in Figure 21 of the datasheet.
ADM691AARW-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm 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-SOIC
ADM691AARW-REEL FAQ
1.How can I place an order for ADM691AARW-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691AARW-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 ADM691AARW-REEL reliable?
The price and inventory of ADM691AARW-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691AARW-REEL is usually 5 days.
3.What payment methods are accepted for ADM691AARW-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691AARW-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691AARW-REEL?
ADM691AARW-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691AARW-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 ADM691AARW-REEL?
For technical support, including ADM691AARW-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691AARW-REEL requirements.
6.How does Aetrix verify that ADM691AARW-REEL is sourced from the original manufacturer or authorized distributors?
All ADM691AARW-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 ADM691AARW-REEL meets industry standards.
7.What is the process for return or replacement of ADM691AARW-REEL?
All ADM691AARW-REEL units undergo pre-shipment inspection (PSI). If there is an issue with ADM691AARW-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 ADM691AARW-REEL part is unused and in its original packaging.
Return procedure for ADM691AARW-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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