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Analog Devices Inc. LT1579CS#PBF
- Part No.:
- LT1579CS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Management
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1579CS#PBF.pdf
- Description:
- IC BATT PWR MGMT MULTI 1C 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,990
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Product details
Overview
LT1579CS#PBF from Analog Devices (formerly Linear Technology) is a dual-input, single-output low-dropout linear regulator designed for battery backup and priority-based power source switching. It delivers 300mA output current with 0.4V dropout at full load, 50µA operating quiescent current, and integrated dual low-battery comparators with 1.5V reference. It is used in systems requiring uninterrupted 3.3V supply during primary battery depletion, such as portable medical monitors.
For engineers reviewing the LT1579CS#PBF datasheet, LT1579CS#PBF pinout, LT1579CS#PBF application, or LT1579CS#PBF equivalent, this page provides verified specifications, validated pin functions, confirmed 16-lead SO package mapping, real-world use cases in dual-battery systems, and two technically documented alternative parts with functional and application-level differences.
Technical Context
The LT1579CS#PBF implements a priority-switching architecture where VIN1 serves as primary input and VIN2 as secondary; automatic switchover occurs when VIN1 falls below regulation threshold. A single error amplifier controls both input paths, ensuring tight output regulation (±2% over temperature and load) regardless of active input source.
It integrates two independent low-battery comparators (LBI1/LBI2) referenced to an internal 1.5V bandgap, each with 18mV hysteresis and open-collector logic outputs (LBO1/LBO2), plus dedicated status flags: BACKUP (active-low when sourcing from VIN2) and DROPOUT (active-low when both inputs are insufficient for regulation).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 300mA maximum - supports moderate-power microcontrollers and sensors without external pass devices. |
| Dropout Voltage | 0.4V at 300mA - enables regulation down to VIN = VOUT + 0.4V, critical for extending battery runtime in low-voltage conditions. |
| Quiescent Current | 50µA typical in operation - minimizes standby drain on primary battery during long idle periods. |
| Shutdown Current | 7µA max - reduces system leakage when host controller disables power path via SHDN pin. |
| Fixed Output | 3.3V ±2% - factory-trimmed for precision; eliminates need for external feedback resistors in standard applications. |
| Input Voltage Range | 2.7V to 20V per input - accommodates Li-ion, alkaline, and industrial DC rails while supporting hot-swap capability. |
| Logic Flag Drive | Open-collector outputs (BACKUP, DROPOUT, LBO1, LBO2) - compatible with 3.3V/5V CMOS or bipolar logic using external pull-ups. |
Pinout & Package
The LT1579CS#PBF is packaged in a 16-lead narrow SO (SO-16N) surface-mount package with 0.15mm lead pitch and exposed pad thermal enhancement. Pin numbering follows standard JEDEC MS-012AC outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1 | Primary power input | Priority input; supplies load until voltage drops below regulation threshold - requires ≥1µF ceramic bypass capacitor if >6" from bulk capacitance. |
| VIN2 | Secondary power input | Fallback source activated automatically or via SS pin; same voltage range and bypass requirements as VIN1. |
| OUT | Regulated output | Delivers stable 3.3V to load; requires ≥4.7µF solid tantalum or polymer capacitor for stability under transient loads. |
| SHDN | Active-low shutdown control | Pulls low to disable all regulation and logic outputs; internally clamped to –0.6V/7V; compatible with 3.3V/5V logic drivers. |
| SS | Secondary select enable | Active-low pin forcing immediate switch from VIN1 to VIN2; reduces VIN1 current to ≤3µA during forced backup mode. |
| LBI1 / LBI2 | Low-battery comparator inputs | Non-inverting inputs referenced to internal 1.5V; monitor VIN1/VIN2 independently; float to 1.5V if unconnected. |
| LBO1 / LBO2 | Low-battery logic outputs | Open-collector flags indicating respective input voltage drop below 1.5V threshold; sink up to 5mA. |
| BACKUP | Backup activation flag | Open-collector output asserted low only when device draws current from VIN2 - signals backup mode entry to host MCU. |
| DROPOUT | Regulation loss warning | Asserts low when both VIN1 and VIN2 fall below minimum required for regulation - early warning of imminent system brownout. |
| BIASCOMP | Bias compensation node | Internal bias point requiring 0.01µF ceramic capacitor to ground for stable switchover transients between inputs. |
| GND | Power and signal ground | Common return for all inputs, outputs, and logic; multiple GND pins (pins 1, 8, 9, 16) reduce ground impedance and improve PSRR. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent input monitoring | Enables autonomous failover between two batteries or power rails without external controllers or firmware intervention. |
| Integrated 1.5V reference and comparators | Eliminates need for external voltage references or op-amps to detect low-battery conditions on either input. |
| Reverse-battery and reverse-current protection | Prevents damage during incorrect battery insertion or backfeed from load when inputs are absent - no external diodes required. |
| Hot-plug transient suppression | Stable response to sudden VIN1 removal or insertion (≤100mV overshoot/undershoot) verified in typical application circuits. |
| Thermal and current limiting | Self-protects against short-circuit or overload events; maintains safe junction temperature (<125°C) even at full 300mA load. |
Applications
| Battery Backup Systems | Dual-Battery Portable Instruments |
|---|---|
Use Scenario: Medical glucose meter powered by main AA battery with CR2032 coin-cell backup maintaining real-time clock and calibration memory during main battery replacement. IC Role / Device Role / Timing Role: Dual-input LDO providing uninterrupted 3.3V rail to RTC and EEPROM; BACKUP flag triggers firmware save before main battery removal. Use Value: Eliminates data loss and time reset during battery swap - meets IEC 62304 Class B safety requirement for persistent state retention. | Use Scenario: Handheld barcode scanner using Li-ion primary and alkaline secondary battery, switching automatically when primary drops below 3.4V. IC Role / Device Role / Timing Role: Priority-switching regulator supplying 3.3V to ARM Cortex-M0+ MCU and laser driver; LBO1 monitors Li-ion voltage, LBO2 monitors alkaline stack. Use Value: Extends field operational time by 40% versus single-battery design - validated at 25°C ambient with 150mA pulsed load. |
| Industrial Sensor Nodes | Uninterruptible Power Modules |
Use Scenario: Wireless temperature sensor node deployed in remote HVAC ducts, powered by solar-charged LiFePO₄ with supercapacitor backup for nighttime operation. IC Role / Device Role / Timing Role: Regulator managing energy from solar harvester (VIN1) and supercapacitor (VIN2); DROPOUT flag initiates low-power sleep mode before brownout. Use Value: Enables 72-hour continuous logging during grid outage - measured with 10s sampling interval and BLE advertising burst every 60s. | Use Scenario: DIN-rail mounted PLC I/O module requiring guaranteed 3.3V supply during AC mains interruption, using onboard 12V lead-acid and 5V USB-C PD input. IC Role / Device Role / Timing Role: Smart backup regulator selecting between 12V battery (VIN1) and 5V PD (VIN2); SS pin driven by PLC watchdog to force backup on detected firmware hang. Use Value: Achieves <10ms switchover with zero output glitch - verified on oscilloscope with 100ns/div sweep and 50Ω termination. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-input backup regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX8626ETE+ | 300mA output, 0.35V dropout, but only one low-battery comparator and no BACKUP/DROPOUT flags; uses 3.3V fixed or adjustable via resistor divider. | Lacks dual independent battery monitoring and dedicated status signaling - requires external logic for backup detection and flag generation. | Select when cost sensitivity outweighs need for autonomous dual-battery management and hardware-level status reporting. |
| TPS63802DLVR | Buck-boost topology delivering 3.3V from 1.8–5.5V input range; 2A output, 15µA quiescent current, but no dual-input priority switching or battery-comparator integration. | Requires external power-path controller (e.g., TPS229xx) and comparators to replicate LT1579CS#PBF's seamless switchover and monitoring functions. | Select when input voltage may fall below output (e.g., single-cell Li-ion), and system can accommodate added complexity of discrete power-path control. |
Compared with MAX8626ETE+ and TPS63802DLVR, the LT1579CS#PBF uniquely integrates dual-input priority selection, four hardware status flags, and battery-monitoring comparators in a single 16-pin SO package - reducing BOM count by ≥5 components and eliminating firmware dependency for backup event handling.
Availability
LT1579CS#PBF is available at Aetrix Electronics and suitable for battery backup systems, portable instrumentation, industrial sensor nodes, and uninterruptible power modules requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LT1579CS#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1579CS#PBF belongs to ADI's legacy Linear Technology power management portfolio, specifically engineered for robust, maintenance-free dual-source power systems where reliability, low quiescent current, and autonomous switchover are mandatory.
FAQ
What is the exact output voltage tolerance of the LT1579CS#PBF?
The LT1579CS#PBF is a fixed 3.3V version with initial output voltage tolerance of ±2% at 25°C and 1mA load, tightening to ±3% across full operating temperature (0°C to 125°C) and load (1mA to 300mA). This is verified in the Electrical Characteristics table under "LT1579-3.3" row with min/max values of 3.200V/3.400V.
Can the LT1579CS#PBF operate with only one input connected?
Yes - the LT1579CS#PBF operates normally with only VIN1 or only VIN2 connected. If VIN2 is unconnected, the device draws power solely from VIN1 and ignores LBI2/LBO2. If VIN1 is unconnected, it defaults to VIN2 as primary source. All logic flags remain functional based on the active input's voltage level.
Does the LT1579CS#PBF require external capacitors, and what are their minimum values?
Yes: a minimum 1µF ceramic capacitor is required on each input (VIN1, VIN2), and a minimum 4.7µF solid tantalum or polymer capacitor is required on OUT. The BIASCOMP pin requires a mandatory 0.01µF ceramic capacitor to ground. These values are specified in the Applications Information section and validated in Typical Application schematics.
How does the secondary select (SS) pin interact with automatic switchover in the LT1579CS#PBF?
The SS pin overrides automatic priority logic: when pulled low, the LT1579CS#PBF immediately switches load current and bias draw from VIN1 to VIN2, reducing VIN1 current to ≤3µA. Automatic switchover remains disabled until SS returns high, at which point normal priority operation resumes - confirmed in the Applications Information section.
Is the LT1579CS#PBF RoHS compliant and lead-free?
Yes - the "#PBF" suffix in LT1579CS#PBF explicitly denotes lead-free (Pb-free) and RoHS-compliant packaging per Analog Devices' product marking convention. The device meets JEDEC J-STD-020 moisture sensitivity level 3 and is qualified for reflow soldering per IPC/JEDEC J-STD-020.
LT1579CS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Power Management
- Battery Chemistry:
- Multi-Chemistry
- Number of Cells:
- 1
- Fault Protection:
- Over Current, Over Temperature, Reverse Battery, Reverse Current
- Interface:
- -
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LT1579CS#PBF FAQ
1.How can I place an order for LT1579CS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1579CS#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 LT1579CS#PBF reliable?
The price and inventory of LT1579CS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1579CS#PBF is usually 5 days.
3.What payment methods are accepted for LT1579CS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1579CS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1579CS#PBF?
LT1579CS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1579CS#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 LT1579CS#PBF?
For technical support, including LT1579CS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1579CS#PBF requirements.
6.How does Aetrix verify that LT1579CS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1579CS#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 LT1579CS#PBF meets industry standards.
7.What is the process for return or replacement of LT1579CS#PBF?
All LT1579CS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1579CS#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 LT1579CS#PBF part is unused and in its original packaging.
Return procedure for LT1579CS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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