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Analog Devices Inc. ADM691AN
- Part No.:
- ADM691AN
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
ADM691AN.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,835
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Product details
Overview
ADM691AN from Analog Devices is a microprocessor supervisory circuit providing precision 4.65 V ±3% reset threshold, 200 ms or adjustable reset timeout, 1.6 s/100 ms 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 ADM691AN datasheet, ADM691AN pinout, ADM691AN application, or ADM691AN equivalent, key selection criteria include its 4.65 V reset threshold compatibility with +5 V ±5% supplies, 250 mA VOUT drive capability, 0.75 Ω VCC-to-VOUT on-resistance, and integrated CEIN/CEOUT RAM write protection logic.
Technical Context
The ADM691AN integrates a precision bandgap-based voltage detector (4.65 V threshold with 15 mV hysteresis), an internal oscillator with dual watchdog modes (100 ms short / 1.6 s long), and a PMOS/NMOS hybrid switchover circuit enabling seamless transition between VCC and VBATT at sub-1 V operation. Its reset generator remains functional down to VCC = 1 V, ensuring controlled shutdown even during deep brownouts.
Chip enable gating uses a low-propagation-delay (6–10 ns) analog switch with 40–150 Ω ON-resistance, while the 1.25 V PFI comparator provides early power-fail warning independent of main supply monitoring. All digital outputs (RESET, WDO, PFO, BATT ON) are open-drain or push-pull with defined sink/source specs per load condition.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V ±3% - matches +5 V supplies with –5%/+10% tolerance; ensures reset assertion before microprocessor instability. |
| Reset Timeout | 200 ms typ (internal oscillator) - holds processor in reset long enough for power and clock stabilization post-power-up. |
| VCC-to-VOUT RON | 0.75 Ω typ - limits voltage drop to ≤187 mV at 250 mA, enabling direct CMOS RAM VDD supply without external pass transistor. |
| Watchdog Timeout | 1.6 s (long) or 100 ms (short) - configurable via OSC SEL/OSC IN; first timeout after reset is always 1.6 s for safe boot recovery. |
| Battery Backup Current | 0.04 µA typ - enables multi-year operation on coin cell (e.g., CR2032) during extended VCC loss. |
| PFI Threshold | 1.25 V - allows flexible early-warning sensing of unregulated input or secondary rails using external resistor divider. |
| CEIN-to-CEOUT Delay | 6–10 ns - supports high-speed memory access timing; prevents spurious writes during VCC transients. |
Pinout & Package
ADM691AN is supplied in a 16-pin plastic DIP (N-16) package with 0.3-inch body width and through-hole mounting. Thermal resistance θJA = 135°C/W; max continuous VCC current = 250 mA.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VBATT) | Backup Battery Input | Connects to coin cell or capacitor; enables automatic switchover when VCC drops below VBATT + 0.03 V. |
| 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 Active Indicator | Open-drain output pulled high when VBATT powers VOUT; drives base of external PNP for >250 mA loads. |
| 12 (CEOUT) | Gated Chip Enable Output | Replicates CEIN when VCC > reset threshold; forced high during reset to block RAM writes. |
| 15 (RESET) | Active-Low Reset Output | Push-pull output; asserts low for ≥200 ms after VCC rises above 4.65 V; remains low down to VCC = 1 V. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset & Watchdog Timing | Configurable via external capacitor (COSC) or clock signal - enables precise tuning of Treset = 1200×(C/47 pF) ms and Twd = 600×(C/47 pF) ms. |
| Low-Power Battery Backup Mode | 0.04 µA supply current with VCC < VBATT − 1.2 V - extends backup runtime on small Li-MnO2 cells beyond 10 years. |
| Integrated RAM Write Protection | CEOUT forces high during reset/brownout - prevents corruption of battery-backed SRAM or EEPROM during power faults. |
| Early Power-Fail Warning | 1.25 V PFI comparator with 25 µs response - triggers NMI interrupt tens of milliseconds before VCC crosses 4.65 V reset threshold. |
| Robust Switchover Hysteresis | 60 mV hysteresis on VBATT–VCC switchover - eliminates oscillation during marginal supply transitions near threshold. |
Applications
| Industrial PLC Controllers | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Power monitoring in DIN-rail mounted programmable logic controllers exposed to 24 VDC field supply fluctuations. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, battery-backed RAM retention, and watchdog supervision of real-time control firmware. Use Value: Guarantees deterministic restart after 24 V dips to 18 V; maintains configuration data across 10-second outages using CR2032 backup. |
Use Scenario: Embedded controller in portable ultrasound units requiring fail-safe shutdown before battery depletion. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main 5 V rail and triggers graceful save-to-flash when PFI detects falling input from Li-ion pack. Use Value: 1.25 V PFI comparator enables 300 ms warning before 5 V rail collapses from 4.8 V → 4.4 V, allowing full image buffer flush. |
| Automotive Body Control Modules | Point-of-Sale Terminal Firmware Recovery |
Use Scenario: Microcontroller supervision in 12 V automotive subsystems subject to load-dump and cold-crank transients. IC Role / Device Role / Timing Role: Resets MCU during cranking (VCC dips to 3.2 V), holds RESET low until stable 5 V restored, and gates CE to prevent EEPROM corruption. Use Value: 1 V minimum operating VCC ensures reset assertion continuity during worst-case cold-crank events; 15 µs CEOUT hold time blocks writes. |
Use Scenario: Transaction integrity in retail kiosks where AC power interruption must not corrupt sales log or inventory cache. IC Role / Device Role / Timing Role: Triggers immediate NMI on PFO edge, initiates atomic flash commit, then asserts RESET to halt CPU before VCC falls below 4.65 V. Use Value: Coordinated PFO→NMI and RESET timing ensures zero-loss transaction logging even during sub-50 ms power glitches. |
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 threshold has ±2.5% tolerance (vs. ±3%); 100 µA standby current (vs. 100 µA typ); no TSSOP option. | Same DIP-16 footprint; identical CE gating and watchdog functionality; slightly tighter reset threshold spec. | Select MAX691ACPE+ only if tighter initial threshold tolerance is required and Analog Devices' 0.04 µA battery mode is not critical. |
| TPS3823-46DBVR | Single-supply 4.63 V reset IC (±0.5%); no battery switchover, no watchdog, no CE gating; SOT-23-5 package. | Limited to basic reset-only applications; lacks all ADM691AN's backup, timing, and memory protection features. | Choose TPS3823-46DBVR only for space-constrained designs needing only precision reset - not as functional replacement. |
Compared with MAX691ACPE+, ADM691AN offers lower battery backup current (0.04 µA vs. 1 µA) and official TSSOP support; compared with TPS3823-46DBVR, ADM691AN delivers full supervisory integration (watchdog, CE gating, switchover) at the cost of larger footprint and higher BOM count.
Availability
ADM691AN is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic equipment, automotive body control modules, point-of-sale terminals, and critical microprocessor power monitoring applications requiring stable component supply across extended production lifecycles.
Supply support for ADM691AN 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, Inc. is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control systems.
The ADM691A family was designed specifically for robust microprocessor supervision in harsh environments - integrating reset, watchdog, battery switchover, CE gating, and power-fail warning into a single 16-pin IC for industrial and automotive reliability.
FAQ
What is the guaranteed reset voltage threshold range for ADM691AN?
The ADM691AN has a guaranteed reset voltage threshold range of 4.50 V to 4.75 V at +25°C, with ±3% tolerance over temperature. This 4.65 V nominal threshold is optimized for +5 V ±5% power supplies, ensuring reliable reset assertion before microprocessor operational instability occurs.
Can ADM691AN operate with VCC below 1 V?
No - the ADM691AN reset circuitry remains functional down to VCC = 1 V, but ceases operation below that level. However, the RESET output is guaranteed to stay low down to VCC = 1 V, and for operation below 1 V, an external pull-down resistor on the RESET line is recommended to maintain valid logic state.
How does the ADM691AN handle battery switchover during power failure?
The ADM691AN automatically switches VOUT from VCC to VBATT when VCC falls below VBATT + 0.03 V (power-up) or VBATT − 0.03 V (power-down), with 60 mV hysteresis. In battery mode, VOUT is sourced through a 7 Ω MOSFET, delivering up to 10 mA at <0.15 V dropout, while consuming only 0.04 µA quiescent current.
Is the watchdog timer on ADM691AN disableable?
Yes - the ADM691AN watchdog timer is disabled when the WDI pin is left floating, as an internal resistor network biases it to ~1.6 V (mid-supply). Driving WDI continuously high or low also disables watchdog action, but this requires explicit firmware control and is not recommended for safety-critical systems.
What package options are available for ADM691AN?
The ADM691AN designation specifically refers to the 16-pin plastic DIP (N-16) package. Other variants include ADM691AARN (narrow SOIC), ADM691AARW (wide SOIC), and ADM691AARU (TSSOP); the "AN" suffix denotes the through-hole DIP version with 0.3-inch width and industry-standard pin spacing.
ADM691AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- 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:
- 35ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
ADM691AN FAQ
1.How can I place an order for ADM691AN through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691AN 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 ADM691AN reliable?
The price and inventory of ADM691AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691AN is usually 5 days.
3.What payment methods are accepted for ADM691AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691AN?
ADM691AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691AN 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 ADM691AN?
For technical support, including ADM691AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691AN requirements.
6.How does Aetrix verify that ADM691AN is sourced from the original manufacturer or authorized distributors?
All ADM691AN 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 ADM691AN meets industry standards.
7.What is the process for return or replacement of ADM691AN?
All ADM691AN units undergo pre-shipment inspection (PSI). If there is an issue with ADM691AN, 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 ADM691AN part is unused and in its original packaging.
Return procedure for ADM691AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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