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Analog Devices Inc. LTC2931CF#PBF
- Part No.:
- LTC2931CF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Supply Controllers, Monitors
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LTC2931CF#PBF.pdf
- Description:
- IC 6 PWR SUPPLY MONITOR 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,926
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Product details
Overview
LTC2931CF#PBF from Analog Devices (formerly Linear Technology) is a configurable six-supply voltage monitor IC with adjustable reset and watchdog timers, ±1.5% threshold accuracy over temperature, 52μA quiescent current, and operation down to VCC = 1V. It serves as a system-level power integrity supervisor in multivoltage embedded systems requiring reliable brownout detection and microprocessor supervision.
For engineers reviewing the LTC2931CF#PBF datasheet, LTC2931CF#PBF pinout, LTC2931CF#PBF application, or LTC2931CF#PBF equivalent, key selection criteria include its 20-lead TSSOP package, 0°C to 70°C operating range, 16 programmable voltage threshold combinations (including ADJ/–ADJ modes), and independent open-drain comparator outputs per supply rail.
Technical Context
The LTC2931CF#PBF implements six independent high-impedance voltage comparators with user-selectable thresholds via a resistive divider on VPG, referencing a buffered 1.210V internal reference. Each comparator drives an open-drain output (COMP1–COMP6) with weak 6μA pull-up to V2.
Reset assertion is controlled by a capacitor-programmable timeout (CRT pin, 2ms/nF scaling), while watchdog timing is set independently via CWT (20ms/nF). RST output remains valid down to VCC = 1V, and glitch immunity ensures robust operation during supply transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | VCC = 1V minimum for RST logic state; internal operation requires ≥2.3V (comparators) or ≥2.4V (mode selection) |
| Threshold Accuracy | ±1.5% over full temperature range - enables tight margining for 5% or tighter supply tolerances |
| Quiescent Current | 52μA typical - supports battery-powered and ultra-low-power systems without compromising supervision coverage |
| Adjustable Timers | CRT sets reset timeout (2ms/nF); CWT sets watchdog timeout (20ms/nF) - allows precise matching to processor boot and watchdog requirements |
| Comparator Inputs | Six inputs (V1–V6): V1/V2 fixed (5V/3.3V/3V/2.5V), V3/V4 selectable (1.8V/1.5V/ADJ/–ADJ), V5/V6 always ADJ - supports mixed-rail monitoring including negative supplies |
| Output Drive | Open-drain COMP1–COMP6 and RST/WDO with 6μA internal pull-up to V2 - permits external pull-up to higher voltages or faster rise times |
| Operating Temperature | 0°C to 70°C - specified for commercial-grade applications including desktop, telecom, and industrial control systems |
Pinout & Package
Package: 20-lead plastic TSSOP (F package), 4.4mm × 6.5mm body, 0.65mm pitch, RoHS-compliant lead-free finish (PBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COMP5 (1) | Comparator Output 5 | Open-drain logic output indicating V5 > threshold; pulled up internally to V2 (6μA); may be externally pulled higher |
| V5 (2) | Adjustable Input 5 | High-impedance input with 0.5V nominal threshold; used for positive adjustable monitoring (e.g., 12V, 10V, etc.) |
| COMP3 (3) | Comparator Output 3 | Open-drain logic output for V3 status; same drive characteristics as COMP5 |
| COMP1 (4) | Comparator Output 1 | Real-time indicator of V1 (5V/3.3V) supply health; primary power-good signal in many configurations |
| V3 (5) | Voltage Input 3 | Selectable threshold: 2.5V, 1.8V, 1.5V, or ADJ; tied to V1 if unused |
| V1 (6) | Voltage Input 1 | Primary supply input (5V or 3.3V); greater of V1/V2 defines VCC; requires 0.1μF bypass to GND |
| CRT (7) | Reset Timeout Capacitor | Connects to GND to set reset delay (2ms/nF); open = ~25μs min delay; 47nF = 94ms typical |
| RST (8) | Reset Output | Active-low open-drain reset signal asserted when any monitored supply falls below threshold; guaranteed valid down to VCC = 1V |
| WDO (9) | Watchdog Output | Open-drain watchdog fault indicator; toggles low/high if WDI not strobed within tWD; cleared by WDI edge or RST low |
| WDI (10) | Watchdog Input | Edge-triggered watchdog clear input; rising/falling edge resets CWT timer; internal 10μA pull-up holds high if unconnected |
| CWT (11) | Watchdog Timeout Capacitor | Connects to GND to set watchdog period (20ms/nF); open = ~200μs min; 47nF = 940ms typical; tie to GND to disable |
| GND (12) | Ground Reference | System ground return for all analog and digital circuitry; common reference for VREF, CRT, CWT, and comparator inputs |
| VPG (13) | Threshold Select Input | Accepts voltage divider tap between VREF and GND to select one of 16 preset combinations; no capacitance allowed |
| VREF (14) | Buffered Reference Output | 1.210V ±0.018V buffered reference; sources/sinks ±1mA; drives VPG divider and –ADJ mode level shift |
| V4 (15) | Voltage Input 4 | Selectable: 1.8V, 1.5V, ADJ (0.5V ref), or –ADJ (ground-referenced for negative supplies) |
| V2 (16) | Voltage Input 2 | Secondary supply input (3.3V/3V/2.5V); greater of V1/V2 defines VCC; requires 0.1μF bypass |
| COMP4 (17) | Comparator Output 4 | Open-drain status for V4; supports real-time monitoring of 1.8V, 1.5V, or negative rails |
| COMP2 (18) | Comparator Output 2 | Real-time indicator of V2 supply; used for secondary power-good or sequencing enable |
| V6 (19) | Adjustable Input 6 | Always ADJ mode (0.5V threshold); commonly used for temperature sensing (thermistor divider) or auxiliary supply monitoring |
| COMP6 (20) | Comparator Output 6 | Final comparator output; often assigned to overtemperature or backup supply fault indication |
Key Features
| Feature | Design Value |
|---|---|
| 16 Preset Threshold Combinations | Enables rapid configuration for common multivoltage systems (e.g., 5V/3.3V/2.5V/1.8V/1.5V/ADJ) without custom resistor networks |
| Independent Comparator Outputs | Allows per-rail fault isolation and sequenced power-up control (e.g., enabling DC/DC converters only after upstream rails are stable) |
| –ADJ Mode for Negative Supplies | Supports monitoring of negative rails (e.g., –5.2V) using VREF as level-shift reference - eliminates need for external op-amp circuits |
| Guaranteed RST Operation to 1V | Ensures clean reset assertion during deep brownout or battery sag conditions where other supervisors fail |
| Glitch-Immune Comparators | Prevents false resets due to short-duration supply noise or coupling - critical in noisy industrial or automotive environments |
| Temperature Range: 0°C to 70°C | Validated for commercial applications including desktop PCs, network servers, and telecom line cards where extended temperature is not required |
Applications
| Desktop and Notebook Computers | Multivoltage Systems |
|---|---|
Use Scenario: Monitoring core logic (5V), I/O (3.3V), memory (2.5V/1.8V), and auxiliary (1.5V/1.2V) rails during power-up, runtime, and thermal events. IC Role / Device Role / Timing Role: Centralized power supervisor providing synchronized reset, individual rail status (COMP1–COMP6), and watchdog oversight for CPU firmware. Use Value: Prevents system lockup from undervoltage on any rail; enables graceful shutdown before data corruption occurs. | Use Scenario: Coordinating startup sequence of FPGA, DSP, and analog subsystems each requiring different voltage rails and timing constraints. IC Role / Device Role / Timing Role: Real-time comparator outputs (COMP1–COMP6) act as enable signals for DC/DC converters in strict power-up order. Use Value: Eliminates need for discrete RC timers or CPLD-based sequencing logic - reduces BOM count and layout complexity. |
| Telecom Equipment | Network Servers |
Use Scenario: Supervising redundant 12V, 5V, 3.3V, and –48V distribution in line cards and base station controllers. IC Role / Device Role / Timing Role: V4 in –ADJ mode monitors –48V rail; COMP4 asserts fault; RST triggers system-level alarm and switchover logic. Use Value: Single IC replaces multiple discrete supervisors - improves reliability and reduces board area in space-constrained modules. | Use Scenario: Detecting overtemperature via thermistor on V6 input while simultaneously supervising 12V, 5V, 3.3V, 1.8V, and 1.2V server rails. IC Role / Device Role / Timing Role: COMP6 provides dedicated thermal fault signal; RST initiates graceful CPU throttling or shutdown sequence. Use Value: Integrates thermal and power monitoring without external ADC or microcontroller - lowers system cost and latency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar six-supply monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6816ESE+ | Quad-supply monitor (not six); fixed 2.5V/3.3V/5V thresholds only; no ADJ/–ADJ capability; no watchdog timer | Limited to simpler systems with ≤4 rails; cannot support negative supplies or custom trip points | Select when only basic quad-rail supervision is needed and design cost sensitivity outweighs configurability needs. |
| TPS3808G33DBVR | Single-channel supervisor with 3.3V fixed threshold; no multi-rail capability; no comparator outputs; no VPG programming | Requires six separate ICs to match LTC2931CF#PBF functionality - increases board area and BOM cost significantly | Use only for point-of-load supervision where centralized six-rail monitoring is unnecessary. |
Compared with MAX6816ESE+ and TPS3808G33DBVR, the LTC2931CF#PBF delivers integrated six-rail monitoring, programmable thresholds including negative rails, independent comparator outputs, and watchdog functionality - reducing component count, PCB area, and system-level validation effort in complex multivoltage designs.
Availability
LTC2931CF#PBF is available at Aetrix Electronics and suitable for desktop computers, telecom equipment, and network servers requiring stable component supply with commercial-temperature grade performance and long-term production continuity.
Supply support for LTC2931CF#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 and maintains full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC2931CF#PBF belongs to Linear's precision power monitoring IC family, designed specifically for high-reliability multivoltage systems where accurate, glitch-immune supervision and flexible configuration are mandatory.
FAQ
What is the minimum VCC voltage that guarantees correct RST logic state for LTC2931CF#PBF?
The LTC2931CF#PBF guarantees correct RST logic state down to VCC = 1V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures reliable reset assertion during deep brownout conditions where other supervisors may release prematurely. The internal bandgap reference remains functional above ~2V, but RST output circuitry is explicitly characterized to 1V.
How does the LTC2931CF#PBF support monitoring of negative supply rails like –5.2V?
The LTC2931CF#PBF supports negative rail monitoring via its –ADJ mode on V4 input. In this mode, the internal reference is grounded, and VREF (1.210V) serves as the level-shift reference. A resistive divider between the negative supply and VREF sets the trip point using VTRIP = –VREF × (R3/R4). This eliminates external op-amps and enables direct, accurate supervision of rails such as –5.2V or –12V.
Can the LTC2931CF#PBF be used to implement a power-up sequencing function without external logic?
Yes. The LTC2931CF#PBF's six independent open-drain comparator outputs (COMP1–COMP6) can directly enable DC/DC converters in sequence. For example, COMP1 (V1 OK) enables the 3.3V converter; COMP2 (V2 OK) enables the 1.8V converter; and COMP5 (V5 OK) signals "all rails good" before releasing RST. This real-time, hardware-based sequencing requires no firmware or additional logic devices.
What is the purpose of the VPG pin on the LTC2931CF#PBF, and how is it configured?
The VPG pin selects one of 16 voltage threshold combinations via a resistive divider between VREF and GND. The voltage on VPG is sampled during a 150μs setup period after VCC rises above 2.4V. Table 1 in the datasheet provides exact 1% resistor values (e.g., R1 = 93.1kΩ, R2 = 9.53kΩ for Mode 1). Capacitance must not be added to VPG, as it disrupts sampling accuracy and causes misconfiguration.
Is the LTC2931CF#PBF pin-compatible with other variants like LTC2931IF#PBF or LTC2931HF#PBF?
Yes, the LTC2931CF#PBF is pin-compatible with LTC2931IF#PBF and LTC2931HF#PBF. All share identical 20-lead TSSOP packaging, pinout, electrical interface, and functional behavior. The only difference is operating temperature range: C-grade (0°C to 70°C), I-grade (–40°C to 85°C), and H-grade (–40°C to 125°C). System designs can migrate between grades without PCB changes.
LTC2931CF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Applications:
- Six Power Supply Monitor
- Voltage - Input:
- -
- Voltage - Supply:
- 1V ~ 7V
- Current - Supply:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
LTC2931CF#PBF FAQ
1.How can I place an order for LTC2931CF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2931CF#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 LTC2931CF#PBF reliable?
The price and inventory of LTC2931CF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2931CF#PBF is usually 5 days.
3.What payment methods are accepted for LTC2931CF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2931CF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2931CF#PBF?
LTC2931CF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2931CF#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 LTC2931CF#PBF?
For technical support, including LTC2931CF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2931CF#PBF requirements.
6.How does Aetrix verify that LTC2931CF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC2931CF#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 LTC2931CF#PBF meets industry standards.
7.What is the process for return or replacement of LTC2931CF#PBF?
All LTC2931CF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC2931CF#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 LTC2931CF#PBF part is unused and in its original packaging.
Return procedure for LTC2931CF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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