My Inquiry
My Account
Analog Devices Inc. ADM691AR-REEL
- Part No.:
- ADM691AR-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ADM691AR-REEL.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,652
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
ADM691AR-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. It features a 4.65 V ±3% reset threshold, 200 ms or adjustable reset timeout, 1.6 s/100 ms selectable watchdog timeout, 250 mA VOUT drive capability from VCC, and 1.25 V PFI comparator reference. It is used in industrial controllers and embedded systems requiring reliable power monitoring and nonvolatile memory protection.
For engineers reviewing the ADM691AR-REEL datasheet, ADM691AR-REEL pinout, ADM691AR-REEL application, or ADM691AR-REEL equivalent, key selection criteria include its 4.65 V reset threshold compatibility with +5 V ±5% supplies, battery switchover hysteresis of 60 mV, 0.75 Ω typical VCC-to-VOUT on-resistance, and dual RESET/RESET outputs for active-low and active-high processor interfaces.
Technical Context
The ADM691AR-REEL implements a precision bandgap-based voltage detector for reset generation, an internal oscillator (or external clock/capacitor programmable) for timing control, and complementary PMOS/NMOS switching transistors for seamless VCC/VBATT switchover to VOUT. Its watchdog transition detector monitors WDI edge activity and triggers reset if no transition occurs within the selected timeout period.
Chip enable gating uses a low-propagation-delay (6–10 ns), current-limited buffer between CEIN and CEOUT, which forces CEOUT high during reset assertion regardless of CEIN state. The PFI comparator operates independently with a stable 1.25 V reference and supports hysteresis via external feedback to PFO.
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 operational failure. |
| Reset Timeout | 200 ms typ (adjustable) - holds processor in reset long enough for power and clock stabilization after power-up. |
| Watchdog Timeout | 1.6 s long / 100 ms short (selectable) - provides flexible software execution monitoring with guaranteed first-reset delay of 1.6 s. |
| VCC-to-VOUT RON | 0.75 Ω typ - enables 250 mA continuous output at <300 mV dropout, suitable for CMOS RAM backup without external pass device. |
| Battery Switchover Hysteresis | 60 mV - prevents oscillation during VCC/VBATT crossover near switchover threshold. |
| PFI Reference Voltage | 1.25 V - allows precise early power-fail warning via external resistor divider; remains active down to VBATT – 1.2 V in backup mode. |
| Supply Current (Normal) | 70–100 µA - ultra-low quiescent draw preserves system power budget during active operation. |
| Supply Current (Battery Backup) | 0.04–1 µA - extends backup runtime for SRAM retention using coin-cell or supercapacitor sources. |
Pinout & Package
ADM691AR-REEL is supplied in a 16-pin narrow SOIC (R-16N) package with standard JEDEC MS-012AC footprint, 1.27 mm pitch, and 10.2 mm × 5.3 mm body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Backup Battery Input | Connects to coin cell or capacitor; enables automatic switchover when VCC drops below reset threshold. |
| 2 VOUT | Switched Output | Delivers VCC or VBATT (whichever is higher and valid) to RAM or logic; rated for 250 mA from VCC, 10 mA from VBATT. |
| 3 VCC | Main Power Supply Input | +5 V supply input; monitored for reset generation and CE gating logic; functional down to 1 V. |
| 4 GND | Ground Reference | Common return for all analog and digital functions; must be low-impedance for accurate voltage detection. |
| 5 BATT ON | Battery Status Output | Active-high open-drain signal indicating VBATT is active on VOUT; can drive external PNP base for >250 mA loads. |
| 6 LOW LINE | Low-VCC Indicator | Active-low output asserting when VCC falls below reset threshold; used for system status signaling or interrupt generation. |
| 7 OSC IN | Oscillator Timing Input | Accepts external clock (≤250 kHz) or capacitor (47 pF typical) to program reset/watchdog timeouts; floating selects internal 1.6 s default. |
| 8 OSC SEL | Oscillator Mode Select | High/floating enables internal oscillator; low enables external clock/capacitor mode; includes 10 µA internal pullup. |
| 9 PFI | Power-Fail Input | Noninverting input to 1.25 V comparator; senses auxiliary supply or divided VCC for early fail warning. |
| 10 PFO | Power-Fail Output | Active-low comparator output; typically connected to µP NMI to trigger data save before power loss. |
| 11 WDI | Watchdog Input | Three-level input (low/mid/high); reset triggered if no edge occurs within timeout; floating disables watchdog. |
| 12 CEOUT | Gated Chip Enable Output | Buffered CEIN replica during normal operation; forced high during reset to prevent RAM writes during brownout. |
| 13 CEIN | Chip Enable Input | Directly controls CEOUT; tied to GND or VOUT if unused to avoid floating inputs. |
| 14 WDO | Watchdog Status Output | Active-low status flag that stays low until next WDI transition; indicates watchdog timeout independent of reset state. |
| 15 RESET | Active-Low Reset Output | Open-drain output held low during power-up/down/brownout; complements RESET for active-high processors. |
| 16 RESET | Active-High Reset Output | Inverted open-drain output; provides direct interface to processors requiring high-asserted reset signals. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset & Watchdog Timing | Supports fixed (200 ms / 1.6 s) or user-programmable timeouts via external capacitor or clock - enables design flexibility across diverse firmware architectures. |
| Automatic Battery Backup Switchover | Seamlessly transitions VOUT from VCC to VBATT with 60 mV hysteresis and <1 µA backup current - ensures uninterrupted SRAM retention during main power loss. |
| Dual Active-Low/Active-High RESET Outputs | Provides both RESET (open-drain low) and RESET (open-drain high) - eliminates need for external inverters when interfacing mixed-logic microprocessors. |
| Integrated CE Gating Logic | Forces CEOUT high during reset regardless of CEIN state - guarantees write protection for battery-backed CMOS RAM during unstable supply conditions. |
| Early Power-Fail Warning with Hysteresis Support | 1.25 V PFI reference with optional external hysteresis resistor (R3) - improves noise immunity in noisy industrial power environments. |
| Wide Operating Voltage Range | Functions with VCC as low as 1 V and VBATT ≥2.0 V - maintains supervision integrity through deep brownouts and extended backup operation. |
Applications
| Industrial PLC Controllers | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Programmable logic controllers operating in factory-floor environments with fluctuating 24 V DC supplies converted to +5 V. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, watchdog supervision, and RAM write protection during power interruptions. Use Value: Prevents corrupted ladder logic execution and preserves configuration data in battery-backed SRAM during transient line sags. |
Use Scenario: Portable ultrasound or patient monitor units requiring fail-safe power sequencing and data retention during battery swaps. IC Role / Device Role / Timing Role: Dual-role supervisor: ensures clean boot/reset on AC reconnection and enables graceful shutdown via PFO-triggered NMI before battery depletion. Use Value: Guarantees zero-data-loss shutdown by initiating RAM save routines >100 ms before VCC collapse, leveraging 1.25 V PFI threshold accuracy. |
| Automotive Infotainment Head Units | Telecom Remote Terminal Units |
Use Scenario: In-vehicle infotainment systems powered from 12 V battery with wide cold-crank voltage excursions (down to 3 V). IC Role / Device Role / Timing Role: Voltage supervisor with 4.65 V reset threshold and 1 V minimum VCC operation - asserts reset only when supply is truly invalid. Use Value: Avoids spurious resets during engine cranking while ensuring deterministic restart once stabilized 5 V rail is restored. |
Use Scenario: Outdoor DSLAM or fiber access terminal powered by -48 V telecom supply with local +5 V regulation. IC Role / Device Role / Timing Role: Combines power-fail warning (PFI/PFO), watchdog timer, and battery-switchover for real-time configuration storage during grid outages. Use Value: Enables >72-hour SRAM retention using 0.1 F supercapacitor charged from VOUT, with <1 µA backup current minimizing discharge. |
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 uses ±1.5% reset threshold (4.65 V), 120 ms fixed reset timeout, no adjustable watchdog, and higher 20 µA supply current. | Lacks OSC IN/OSC SEL programmability and PFI hysteresis support; limited to legacy designs requiring drop-in replacement without timing tuning. | Select MAX691ACPE+ only when redesign is impractical and fixed 120 ms reset suffices; ADM691AR-REEL offers superior timing flexibility and lower power. |
| TPS3823MPW | Single-supply 5 V supervisor with 4.63 V threshold, 200 ms reset, but no battery switchover, no CE gating, no PFI comparator, and no watchdog timer. | Suitable only for basic reset-only applications; cannot replace ADM691AR-REEL in systems requiring RAM backup or power-fail warning. | Choose TPS3823MPW for cost-sensitive, minimal-feature applications; retain ADM691AR-REEL where integrated battery management and watchdog are mandatory. |
Compared with MAX691ACPE+, ADM691AR-REEL delivers programmable watchdog timing and 3× lower battery-backup current; versus TPS3823MPW, it adds full battery switchover, CE gating, and PFI/PFO functionality - making it the only single-chip solution for complete µP supervision in resource-constrained embedded systems.
Availability
ADM691AR-REEL is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic equipment, automotive infotainment head units, and telecom remote terminal units requiring stable component supply and long-term lifecycle support.
Supply support for ADM691AR-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, CE gating, and power-fail detection into one compact IC to reduce board space and improve system reliability.
FAQ
What is the reset threshold voltage of the ADM691AR-REEL and how does it affect system compatibility?
The ADM691AR-REEL has a guaranteed reset threshold of 4.65 V ±3%, making it compatible with standard +5 V power supplies having –5% to +10% tolerance. This ensures the microprocessor remains held in reset until the supply stabilizes above 4.5 V, preventing erratic operation during power-up. The ADM691AR-REEL's threshold is tighter than older alternatives like the MAX691A, improving margin against marginal 5 V rails.
Can the ADM691AR-REEL support adjustable watchdog timeout periods, and how is this configured?
Yes, the ADM691AR-REEL supports adjustable watchdog timeout via the OSC SEL and OSC IN pins. With OSC SEL grounded, connecting a capacitor (e.g., 47 pF) from OSC IN to GND sets the timeout to 1.6 s × (C/47 pF). Alternatively, applying an external clock to OSC IN yields Twd = 1024 × (1/fCLK). This configurability allows firmware teams to align timeout behavior precisely with software execution cycles in the ADM691AR-REEL-based system.
How does the ADM691AR-REEL handle battery backup switchover, and what is its maximum supported load current?
The ADM691AR-REEL automatically switches VOUT from VCC to VBATT when VCC drops below the reset threshold and VBATT exceeds VCC by >30 mV. It delivers up to 250 mA from VCC (with 0.75 Ω typical RON) and up to 10 mA from VBATT (with 7 Ω RON). For higher backup currents, the BATT ON output can drive an external PNP transistor - a capability confirmed in the ADM691AR-REEL's functional block diagram and typical application circuits.
Does the ADM691AR-REEL provide both active-low and active-high reset outputs, and why is this important?
Yes, the ADM691AR-REEL provides two dedicated reset outputs: open-drain RESET (active-low) and open-drain RESET (active-high). This eliminates the need for external level-shifting or inversion circuitry when interfacing with microprocessors that require either polarity - such as ARM Cortex-M series (often active-low) versus certain legacy DSPs (requiring active-high). Both outputs are synchronized and asserted simultaneously during reset events in the ADM691AR-REEL.
What role does the PFI/PFO function play in system-level power management using the ADM691AR-REEL?
The PFI input compares an external voltage (e.g., from a resistor divider on the unregulated input) against a precise 1.25 V internal reference; when PFI falls below ~1.25 V, PFO asserts low. This provides early power-fail warning - typically 10–50 ms before VCC crosses the 4.65 V reset threshold - allowing the microprocessor to execute critical save routines. The ADM691AR-REEL's PFI remains functional even in battery backup mode (down to VBATT – 1.2 V), enabling continuous monitoring during extended outages.
ADM691AR-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:
- 35ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
ADM691AR-REEL FAQ
1.How can I place an order for ADM691AR-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM691AR-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 ADM691AR-REEL reliable?
The price and inventory of ADM691AR-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691AR-REEL is usually 5 days.
3.What payment methods are accepted for ADM691AR-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691AR-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM691AR-REEL?
ADM691AR-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM691AR-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 ADM691AR-REEL?
For technical support, including ADM691AR-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691AR-REEL requirements.
6.How does Aetrix verify that ADM691AR-REEL is sourced from the original manufacturer or authorized distributors?
All ADM691AR-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 ADM691AR-REEL meets industry standards.
7.What is the process for return or replacement of ADM691AR-REEL?
All ADM691AR-REEL units undergo pre-shipment inspection (PSI). If there is an issue with ADM691AR-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 ADM691AR-REEL part is unused and in its original packaging.
Return procedure for ADM691AR-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ADM691AR-REEL Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
