My Inquiry
My Account
Analog Devices Inc. LTC694CN8#PBF
- Part No.:
- LTC694CN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LTC694CN8#PBF.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,617
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC694CN8#PBF from Analog Devices (formerly Linear Technology) is an 8-pin microprocessor supervisory IC integrating power-on reset, battery backup switching, power-fail warning, and watchdog timer functions. It features a 4.65V precision reset threshold, guaranteed RESET assertion down to VCC = 1V, 1.5mA max supply current, and 140ms minimum reset active time. It is used in battery-backed CMOS RAM systems requiring reliable power monitoring and fail-safe memory protection.
For engineers reviewing the LTC694CN8#PBF datasheet, LTC694CN8#PBF pinout, LTC694CN8#PBF application, or LTC694CN8#PBF equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters (140ms reset, 1.6s/100ms watchdog), battery switchover behavior (70mV turn-on, 50mV turn-off), and validated alternatives for microprocessor supervisory design.
Technical Context
The LTC694CN8#PBF implements a bandgap-referenced voltage comparator (C1) for precise 4.65V ±150mV reset threshold detection with 40mV hysteresis, ensuring immunity to VCC transients. Its internal charge-pumped NMOS switch delivers up to 50mA to VOUT with 5Ω typical on-resistance during main power operation.
In battery backup mode, a 125Ω PMOS switch connects VBATT to VOUT, enabling standby current as low as 1µA while maintaining VOUT regulation. The watchdog timer uses either an internal oscillator (1.6s/100ms timeout) or external clock input via OSC IN, with timeout reset triggered by WDI transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V typical; ensures µP reset before VCC drops below 4.75V, preventing unstable operation. |
| Reset Active Time | 140ms minimum; holds µP in reset long enough for full power stabilization after brownout recovery. |
| Watchdog Timeout | 1.6s (long) / 100ms (short); configurable via OSC SEL to match system firmware watchdog service intervals. |
| VOUT Dropout | 50mV at 1mA; enables stable CMOS RAM biasing even under marginal VCC conditions. |
| Battery Switchover | 70mV turn-on / 50mV turn-off hysteresis; prevents oscillation when VCC ≈ VBATT during power transitions. |
| Supply Current | 1.5mA max (active), 1µA max (battery backup); minimizes primary supply load and extends backup runtime. |
| RESET Low Voltage | 200mV max at VCC = 1V, 10µA sink; guarantees clean logic-low reset signal even during deep brownout. |
Pinout & Package
Package: 8-lead PDIP (N8), through-hole, 0°C to 70°C operating temperature range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Main 5V supply input | Power source for internal circuitry and VOUT during normal operation; requires 0.1µF bypass capacitor. |
| VOUT | Backed-up memory supply output | Delivers regulated power to CMOS RAM; switches automatically between VCC and VBATT based on comparator C2 decision. |
| PFI | Power-fail input | Noninverting input to comparator C3; monitors external voltage divider to trigger early PFO warning before reset. |
| GND | Analog/digital ground reference | Common return path for all internal circuits and external bypass capacitors. |
| WDI | Watchdog timer input | Three-level input (high/low/floating); transitions reset watchdog timer; floating disables function. |
| VBATT | Battery backup supply input | Source for VOUT during VCC loss; operates from 2.0V to 4.25V; connect to GND if unused. |
| PFO | Power-fail output | Active-low open-drain output signaling impending supply failure; forced low when VCC < VBATT. |
| RESET | Microprocessor reset output | Active-low push-pull output; asserted when VCC < 4.65V or VBATT, guaranteed functional down to VCC = 1V. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset at VCC = 1V | Ensures µP remains held in defined reset state during severe brownouts, eliminating undefined behavior. |
| Integrated battery switchover | Automatic NMOS/PMOS switching eliminates need for external diodes or MOSFETs in RAM backup paths. |
| Adjustable power-fail warning | PFI/PFO pair allows user-defined trip point via external resistor divider, enabling customizable shutdown timing. |
| Watchdog with dual timeout modes | Configurable long/short periods support both critical safety checks and periodic firmware health verification. |
| Low-quiescent battery standby | 1µA max VBATT current preserves lithium or supercapacitor backup energy for months of storage. |
Applications
| Industrial Control PLCs | Medical Data Loggers |
|---|---|
Use Scenario: Maintaining volatile configuration registers and real-time clock during AC mains interruption. IC Role / Device Role / Timing Role: Supervisory controller providing reset hold, RAM backup switching, and power-fail interrupt generation. Use Value: Prevents data corruption during brief outages by guaranteeing 140ms reset assertion and sustaining VOUT from VBATT with <1µA drain. |
Use Scenario: Preserving patient measurement history in portable ECG monitors during battery replacement. IC Role / Device Role / Timing Role: Battery switchover manager and watchdog enforcer ensuring continuous memory integrity. Use Value: Enables hot-swap of backup cells without spurious resets via controlled VBATT switchover hysteresis and BATT ON status signaling. |
| Automotive Infotainment | Smart Metering Systems |
Use Scenario: Securing firmware state and calibration tables during vehicle ignition cycling or alternator voltage dips. IC Role / Device Role / Timing Role: Power monitor with 4.65V reset threshold and 40mV hysteresis rejecting engine cranking noise. Use Value: Eliminates false resets caused by transient VCC sags below 4.75V while ensuring deterministic recovery above 4.65V. |
Use Scenario: Protecting tariff and consumption data in utility meters during grid instability or battery depletion. IC Role / Device Role / Timing Role: Dual-function supervisor delivering both power-fail warning (PFO) and unconditional reset (RESET). Use Value: Allows 8ms+ firmware-initiated graceful shutdown before VCC collapse, using PFO interrupt to trigger EEPROM write completion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690ACPA+ | 4.65V reset threshold, 200ms reset timeout, no integrated watchdog timer, 8-pin PDIP package. | Lacks WDI/WDO functionality; requires external circuitry for watchdog capability. | Select when watchdog is unnecessary and legacy MAX690 footprint compatibility is required. |
| TPS3823-46DBVR | 4.63V reset threshold, 200ms reset delay, no battery backup or PFI/PFO, SOT-23-5 package. | Provides only reset supervision; no RAM backup switching, power-fail warning, or watchdog. | Select for space-constrained designs where only basic reset functionality is needed. |
Compared with LTC694CN8#PBF, MAX690ACPA+ offers identical reset accuracy but omits watchdog and battery management, while TPS3823-46DBVR reduces size and cost at the expense of all auxiliary supervisory functions-making LTC694CN8#PBF uniquely suited for integrated power-fail + backup + watchdog systems.
Availability
LTC694CN8#PBF is available at Aetrix Electronics and suitable for industrial control PLCs, medical data loggers, automotive infotainment units, smart metering systems, and battery-powered instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC694CN8#PBF 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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.
The LTC694CN8#PBF belongs to the LTC690 family of microprocessor supervisory circuits, designed specifically for robust power monitoring, battery-backed memory protection, and fail-safe system recovery in mission-critical embedded applications.
FAQ
What is the guaranteed minimum reset active time for LTC694CN8#PBF?
The LTC694CN8#PBF guarantees a minimum reset active time of 140ms after VCC rises above the 4.65V threshold. This value is fixed (not adjustable) and applies across the full 0°C to 70°C operating temperature range. The 140ms duration ensures sufficient time for microprocessor and peripheral power rails to stabilize before release from reset, and is distinct from the 35ms minimum of the LTC690-series counterparts.
Does LTC694CN8#PBF support battery backup for CMOS RAM, and how does switchover work?
Yes, LTC694CN8#PBF supports battery backup via its VBATT and VOUT pins. When VCC falls to within 50mV of VBATT, the internal PMOS switch connects VBATT to VOUT, sustaining RAM power. Switchover includes 20mV hysteresis to prevent oscillation. In backup mode, VOUT regulation degrades to 125Ω output impedance, and supply current drops to ≤1µA - enabling multi-month retention on coin-cell batteries.
Can LTC694CN8#PBF generate an early power-fail warning, and how is it configured?
Yes, LTC694CN8#PBF provides early power-fail warning using the PFI input and PFO output. PFI is compared against an internal 1.3V reference; when the divided-down supply voltage at PFI drops below 1.3V, PFO goes low. Configuration requires an external resistor divider (e.g., 51kΩ/10kΩ) from VCC to GND, with PFI tapped between them - allowing trip point tuning independent of the 4.65V reset threshold.
What watchdog timeout periods does LTC694CN8#PBF support, and how are they selected?
LTC694CN8#PBF supports two watchdog timeout periods: 1.6 seconds (long) and 100ms (short). Selection is controlled by the OSC SEL pin: when OSC SEL is high or floating, the internal oscillator sets the timeout; driving OSC SEL low enables external clock input via OSC IN. The initial timeout after power-on or reset is always 1.6 seconds, regardless of OSC SEL state.
Is LTC694CN8#PBF pin-compatible with other members of the LTC690 family, such as LTC690CN8#PBF?
No, LTC694CN8#PBF is not pin-compatible with LTC690CN8#PBF. While both use the same 8-pin PDIP package and share VCC, VOUT, PFI, GND, WDI, VBATT, PFO, and RESET pin positions, their internal functionality differs: LTC694CN8#PBF has fixed 140ms reset timing and lacks the LOWLINE output present on LTC691/LTC695, and its watchdog behavior is identical to LTC690 but with longer reset duration. Pin mapping matches, but system-level timing and feature assumptions must be revalidated.
LTC694CN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Open Drain or Open Collector
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LTC694CN8#PBF FAQ
1.How can I place an order for LTC694CN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC694CN8#PBF 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 LTC694CN8#PBF reliable?
The price and inventory of LTC694CN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC694CN8#PBF is usually 5 days.
3.What payment methods are accepted for LTC694CN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC694CN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC694CN8#PBF?
LTC694CN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC694CN8#PBF 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 LTC694CN8#PBF?
For technical support, including LTC694CN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC694CN8#PBF requirements.
6.How does Aetrix verify that LTC694CN8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC694CN8#PBF 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 LTC694CN8#PBF meets industry standards.
7.What is the process for return or replacement of LTC694CN8#PBF?
All LTC694CN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC694CN8#PBF, 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 LTC694CN8#PBF part is unused and in its original packaging.
Return procedure for LTC694CN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC694CN8#PBF 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…
