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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

Analog Devices Inc. ADM691ANZ

Name: ADM691ANZ
Brand: Analog Devices Inc.
SKU: ADM691ANZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ADM691ANZ

Manufacturer:: Analog Devices Inc.

Category:: Supervisors

Package:: 16-DIP (0.300", 7.62mm)

Datasheet:: ADM691ANZ.pdf

Description:: IC SUPERVISOR 1 CHANNEL 16DIP

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Product details

Overview

ADM691ANZ 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 fixed reset timeout (adjustable), 1.6 s/100 ms selectable watchdog timeout, and automatic VCC/VBATT switching to VOUT with ≤0.75 Ω on-resistance. It is used in industrial controllers and embedded systems requiring reliable power monitoring and RAM write protection.

For engineers reviewing the ADM691ANZ datasheet, ADM691ANZ pinout, ADM691ANZ application, or ADM691ANZ equivalent, key selection considerations include its 4.65 V reset threshold compatibility with +5 V ±5% supplies, dual-reset outputs (active-low RESET and active-high RESET), battery switchover down to 1 V VCC operation, and integrated CEIN/CEOUT gating for CMOS RAM write protection.

Technical Context

The ADM691ANZ implements a precision bandgap-based voltage detector for reset generation, a dual-mode oscillator (internal RC or external clock/capacitor) controlling both reset delay and watchdog timeout, and a PMOS/NMOS hybrid switchover architecture enabling seamless transition between VCC and VBATT with <1 µA battery standby current. Its watchdog uses edge-triggered WDI input with transition detection logic and configurable long/short timeout modes.

Chip enable gating employs a low-propagation-delay (≤10 ns) analog switch with 40–150 Ω on-resistance, while the power-fail comparator uses a stable 1.25 V internal reference and supports hysteresis via external feedback. All digital outputs (RESET, WDO, PFO, BATT ON, LOW LINE) are open-drain or push-pull with specified sink/source drive capability under defined load conditions.

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 brownout.
Reset Timeout	200 ms typ (fixed) or adjustable - holds processor in reset long enough for power and clock stabilization after power-up.
Watchdog Timeout	1.6 s (long) or 100 ms (short) - provides flexible software execution monitoring; first timeout after reset is always 1.6 s.
VCC→VOUT On-Resistance	0.75 Ω typ - enables up to 250 mA output with ≤188 mV drop at 250 mA, suitable for direct CMOS RAM supply.
Battery Standby Current	0.04 µA typ - minimizes battery drain during extended backup operation, extending shelf life of backup capacitors or cells.
Power-Fail Reference	1.25 V internal - allows precise early warning of supply degradation via external resistor divider on PFI pin.
Operating Voltage Range	VCC = 4.75–5.5 V; VBATT = 2.0–5.5 V - supports operation with depleted batteries down to 2.0 V and maintains functionality with VCC as low as 1 V.

Pinout & Package

ADM691ANZ is supplied in a 16-pin plastic DIP (N-16) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch; lead finish is matte tin.

Pin/Terminal	Circuit Role	Design Meaning
1 VBATT	Backup battery input	Connects to external battery or capacitor; internally switched to VOUT when VCC falls below reset threshold and VBATT > VCC.
2 VOUT	Switched output supply	Delivers VCC or VBATT depending on switchover logic; powers CMOS RAM or other low-power logic during main supply failure.
3 VCC	Main power supply input	+5 V nominal supply; monitored for reset generation and used as reference for all internal comparators and timers.
4 GND	Ground reference	Common return path for all analog and digital functions; must be low-impedance for accurate voltage detection.
5 BATT ON	Battery switchover status output	Active-high open-drain signal indicating VBATT is active on VOUT; can drive base of external PNP transistor for higher current.
6 LOW LINE	Low VCC indicator	Active-low output asserting when VCC drops below reset threshold; used for system-level fault signaling or interrupt generation.
7 OSC IN	Oscillator input/control	Accepts external clock (≤250 kHz) or capacitor (47 pF typical) to configure reset/watchdog timing; floating selects 1.6 s mode.
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	Non-inverting input to 1.25 V comparator; driven by external resistor divider to detect pre-failure supply droop.
10 PFO	Power-fail output	Active-low open-drain output signaling PFI < 1.25 V; typically connected to µP NMI pin for early shutdown sequence.
11 WDI	Watchdog input	Three-level input (low/mid/high); reset triggered if no edge occurs within timeout period; floating disables watchdog.
12 CEOUT	Gated chip-enable output	Buffered replica of CEIN when VCC > reset threshold; forced high during reset to prevent RAM writes during power instability.
13 CEIN	Chip-enable input	Direct connection to µP CE/CS line; gated through internal analog switch to CEOUT with ≤10 ns propagation delay.
14 WDO	Watchdog status output	Active-low open-drain output reflecting watchdog state; goes low on timeout and resets only on next WDI edge.
15 RESET	Active-low reset output	Open-drain output asserted low during power-up, brownout, or watchdog timeout; 200 ms minimum pulse width.
16 RESET	Active-high reset output	Inverted complement of RESET; provides compatible reset signal for processors requiring active-high assertion.

Key Features

Feature	Design Value
Integrated battery switchover	Automatic VCC/VBATT selection to VOUT with <1 µA battery standby current and 60 mV hysteresis prevents oscillation during switchover.
Dual reset outputs	Simultaneous active-low RESET and active-high RESET eliminate need for external inverters in mixed-logic systems.
Configurable watchdog timer	Selectable 100 ms / 1.6 s timeout periods plus external clock/capacitor adjustment enables precise software health monitoring.
CMOS RAM write protection	CEIN-to-CEOUT gating forces CEOUT high during reset, blocking write access to battery-backed RAM during power transients.
Early power-fail warning	1.25 V precision reference with PFI/PFO interface allows programmable trip point 10–100 ms before VCC reaches reset threshold.

Applications

Industrial Controller Power Monitoring	Automotive Body Control Module
Use Scenario: PLC or motion controller operating in factory environments with noisy 24 V DC supplies converted to +5 V. IC Role / Device Role / Timing Role: ADM691ANZ monitors regulated +5 V rail, asserts RESET on brownout, switches to backup capacitor during brief outages, and gates RAM CE to preserve configuration data. Use Value: Prevents corrupted firmware updates and maintains real-time clock/calendar state during 10–500 ms supply interruptions common in industrial settings.	Use Scenario: BCM managing door locks, lighting, and sensors in 12 V automotive electrical system with wide temperature range. IC Role / Device Role / Timing Role: ADM691ANZ detects battery voltage sag during cranking (VCC dip to ~3.5 V), triggers early PFO warning to save EEPROM settings, and maintains RAM with VBATT during engine start. Use Value: Enables safe parameter retention and avoids re-initialization of security keys or calibration data across repeated cold cranking cycles.
Medical Infusion Pump Controller	Point-of-Sale Terminal with Backup RAM
Use Scenario: Battery-powered infusion pump with safety-critical MCU requiring guaranteed reset behavior and nonvolatile memory integrity. IC Role / Device Role / Timing Role: ADM691ANZ provides fail-safe reset during AC adapter loss, monitors main Li-ion cell via PFI divider, and gates SRAM CE to block writes during low-VCC transitions. Use Value: Meets IEC 62304 Class C requirements by ensuring deterministic reset timing and preventing memory corruption during power faults.	Use Scenario: Retail terminal using CMOS SRAM for transaction buffering with coin-cell backup and frequent power cycling. IC Role / Device Role / Timing Role: ADM691ANZ manages switchover from 5 V wall adapter to CR2032 coin cell, asserts RESET during plug-unplug events, and uses WDI toggling to verify host CPU liveness. Use Value: Guarantees zero-data-loss transaction logging across 10,000+ power cycles with <0.1 µA battery drain in backup mode.

Industrial Controller Power Monitoring

Automotive Body Control Module

Use Scenario: PLC or motion controller operating in factory environments with noisy 24 V DC supplies converted to +5 V.

IC Role / Device Role / Timing Role: ADM691ANZ monitors regulated +5 V rail, asserts RESET on brownout, switches to backup capacitor during brief outages, and gates RAM CE to preserve configuration data.

Use Value: Prevents corrupted firmware updates and maintains real-time clock/calendar state during 10–500 ms supply interruptions common in industrial settings.

Use Scenario: BCM managing door locks, lighting, and sensors in 12 V automotive electrical system with wide temperature range.

IC Role / Device Role / Timing Role: ADM691ANZ detects battery voltage sag during cranking (VCC dip to ~3.5 V), triggers early PFO warning to save EEPROM settings, and maintains RAM with VBATT during engine start.

Use Value: Enables safe parameter retention and avoids re-initialization of security keys or calibration data across repeated cold cranking cycles.

Medical Infusion Pump Controller

Point-of-Sale Terminal with Backup RAM

Use Scenario: Battery-powered infusion pump with safety-critical MCU requiring guaranteed reset behavior and nonvolatile memory integrity.

IC Role / Device Role / Timing Role: ADM691ANZ provides fail-safe reset during AC adapter loss, monitors main Li-ion cell via PFI divider, and gates SRAM CE to block writes during low-VCC transitions.

Use Value: Meets IEC 62304 Class C requirements by ensuring deterministic reset timing and preventing memory corruption during power faults.

Use Scenario: Retail terminal using CMOS SRAM for transaction buffering with coin-cell backup and frequent power cycling.

IC Role / Device Role / Timing Role: ADM691ANZ manages switchover from 5 V wall adapter to CR2032 coin cell, asserts RESET during plug-unplug events, and uses WDI toggling to verify host CPU liveness.

Use Value: Guarantees zero-data-loss transaction logging across 10,000+ power cycles with <0.1 µA battery drain in backup mode.

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 16-pin DIP; 4.65 V reset threshold; identical functional block diagram; same 200 ms reset timeout and 1.6 s watchdog default.	Legacy Maxim part with identical feature set but discontinued production; limited new-design suitability due to obsolescence risk.	Select ADM691ANZ for new designs requiring active manufacturing support, extended temperature range (–40°C to +85°C), and guaranteed long-term availability.
TPS3823MPW	Single-supply 5-pin SOT-23; no battery switchover, no CE gating, no watchdog; only reset + PFI/PFO; 4.63 V threshold; 200 ms timeout.	Suitable only for basic reset supervision without backup or memory protection; lacks VOUT switching, WDI, CEOUT, BATT ON, and dual RESET outputs.	Choose ADM691ANZ when full supervisory functionality-including battery backup, watchdog, and RAM write protection-is required in a single IC.

Compared with MAX691ACPE+, ADM691ANZ offers identical core functionality with superior long-term supply chain assurance; compared with TPS3823MPW, ADM691ANZ delivers comprehensive system-level supervision including battery management and memory protection not available in simplified reset-only devices.

Availability

ADM691ANZ is available at Aetrix Electronics and suitable for industrial controllers, automotive body electronics, medical infusion pumps, and point-of-sale terminals requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for ADM691ANZ 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 power supervision in harsh environments, combining reset, watchdog, battery switchover, and memory protection in one IC to reduce system-level component count and improve reliability.

FAQ

What is the reset threshold voltage of the ADM691ANZ and how does it affect system compatibility?

The ADM691ANZ 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 reliable reset assertion before most microprocessors enter undefined operation, and the hysteresis prevents chatter near the trip point. The ADM691ANZ's threshold is distinct from the 4.4 V variant (ADM693A), so selecting ADM691ANZ confirms design alignment with tighter 5 V nominal regulation.

Can the ADM691ANZ operate with VCC below 4.75 V, and what happens to its functionality?

Yes, the ADM691ANZ remains fully operational with VCC as low as 1 V. During brownout, RESET stays asserted until VCC rises above 4.65 V, then holds low for 200 ms. Battery switchover continues functioning, and VOUT tracks VBATT. However, the internal oscillator and watchdog are disabled when VCC drops below ~2.5 V, and CEOUT is forced high to protect RAM. So ADM691ANZ maintains critical supervision functions even under severe undervoltage conditions.

How does the ADM691ANZ handle battery backup switching, and what is the maximum continuous current it can deliver from VOUT?

The ADM691ANZ uses an internal PMOS transistor to switch VCC to VOUT (on-resistance ≤0.75 Ω) and a 7 Ω NMOS for VBATT-to-VOUT backup. It delivers up to 250 mA continuously from VCC and supports peak currents >250 mA with external bypass capacitance. In battery mode, it draws only 0.04 µA standby current. For loads exceeding 250 mA, the BATT ON output can drive an external PNP transistor-enabling scalable backup current while retaining ADM691ANZ's control intelligence.

What are the options for configuring the watchdog timeout period on the ADM691ANZ?

The ADM691ANZ supports three watchdog timeout configurations: (1) 1.6 s default (OSC SEL and OSC IN floating), (2) 100 ms short period (OSC IN grounded, OSC SEL floating), or (3) adjustable period using external clock or capacitor (OSC SEL grounded). With a 47 pF capacitor on OSC IN, timeout is 1.6 s; scaling linearly with capacitance. External clock input allows precise timing: Twd = 1024 × (1/fCLK). All modes apply identically to the ADM691ANZ without hardware modification.

Does the ADM691ANZ provide both active-low and active-high reset outputs, and how are they used?

Yes, the ADM691ANZ provides two independent reset outputs: pin 15 (RESET) is active-low open-drain, and pin 16 (RESET) is active-high push-pull. This eliminates the need for external inverters in systems mixing logic families. RESET directly interfaces with µP reset pins requiring low assertion, while RESET drives peripherals or FPGAs needing high-active reset. Both outputs share the same timing-200 ms minimum pulse width after VCC recovery-and are synchronized to the internal reset generator in ADM691ANZ.

ADM691ANZ Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc.

Series:: -

Package/Case:: 16-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Active

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

ADM691ANZ FAQ

1.How can I place an order for ADM691ANZ through Aetrix?

Please submit a Request for Quotation (RFQ) for ADM691ANZ 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 ADM691ANZ reliable?

The price and inventory of ADM691ANZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM691ANZ is usually 5 days.

3.What payment methods are accepted for ADM691ANZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM691ANZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ADM691ANZ?

ADM691ANZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ADM691ANZ 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 ADM691ANZ?

For technical support, including ADM691ANZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM691ANZ requirements.

6.How does Aetrix verify that ADM691ANZ is sourced from the original manufacturer or authorized distributors?

All ADM691ANZ 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 ADM691ANZ meets industry standards.

7.What is the process for return or replacement of ADM691ANZ?

All ADM691ANZ units undergo pre-shipment inspection (PSI). If there is an issue with ADM691ANZ, 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 ADM691ANZ part is unused and in its original packaging.

Return procedure for ADM691ANZ:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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