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Analog Devices Inc. LTC1731EMS8-4.1#TRPBF
- Part No.:
- LTC1731EMS8-4.1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1731EMS8-4.1#TRPBF.pdf
- Description:
- IC BATT CHG MULT-CHEM 1CEL 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,815
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Product details
Overview
LTC1731EMS8-4.1 from Analog Devices (formerly Linear Technology) is a single-cell lithium-ion linear battery charger controller with internal 4.1V float voltage regulation, ±1% output voltage accuracy, 5% charge current accuracy via external sense resistor, and automatic trickle-to-CC-to-CV charging sequence. It operates from 4.5V to 12V input and supports programmable charge current up to 585mA using RPROG and RSENSE.
For engineers reviewing the LTC1731EMS8-4.1 datasheet, LTC1731EMS8-4.1 pinout, LTC1731EMS8-4.1 application, or LTC1731EMS8-4.1 equivalent, key selection criteria include its 8-pin MSOP package, C/10 end-of-charge detection, 7µA sleep-mode battery drain, programmable timer termination, and compatibility with external P-channel MOSFET or high-gain PNP pass devices.
Technical Context
The LTC1731EMS8-4.1 implements a precision linear control loop using an internal 2.457V reference, trimmed 800Ω resistor, and current amplifier to servo external pass device gate/base. Its voltage amplifier regulates BAT pin to 4.1V ±1% via internal resistor divider, while the C/10 comparator monitors charge current decay for termination.
It integrates undervoltage lockout (4.1V threshold with 200mV hysteresis), automatic low-voltage cell preconditioning (trickle at 10% of full current until VBAT > 2.457V), and shutdown control via floating PROG pin. The TIMER pin accepts external capacitor for 3-hour base timing (tTIMER = CTIMER × 3h / 0.1µF) or enables constant-current-only mode when tied to VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Float Voltage | 4.1V ±1% - precisely regulates single Li-ion cell to safe termination voltage without external feedback components. |
| Charge Current Accuracy | ±5% - set by external RSENSE and RPROG; enables repeatable 465–535mA full-scale current with 19.6kΩ/0.2Ω configuration. |
| Sleep Mode Drain | 7µA typical - minimizes battery self-discharge when input supply is removed, extending standby time in portable systems. |
| C/10 Detection Threshold | 25–100mA - triggers CHRG pin state change to indicate end-of-charge; latched after 320ms delay to reject transients. |
| Input Voltage Range | 4.5V to 12V - supports USB-powered, wall adapter, and multi-cell battery input sources with 4.1V UVLO protection. |
| Trickle Threshold | 2.35V to 2.55V - initiates 10% preconditioning current for deeply discharged cells; prevents damage from forced fast charging. |
| Timer Accuracy | ±10% - determines total charge duration via external CTIMER; allows configurable safety timeout independent of battery impedance. |
Pinout & Package
Package: 8-lead plastic MSOP (3mm × 3mm, 0.65mm pitch), RoHS-compliant, thermal resistance θJA = 200°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BAT (Pin 1) | Battery voltage sense input | Connects to Li-ion anode; internal 720Ω/100kΩ divider sets 4.1V regulation point; requires ≥10µF bypass for stability. |
| CHRG (Pin 2) | Open-drain charge status output | Drives LED or µC input: low during CC/CV charge, 100µA pull-down at C/10, high-Z after timer expiry or shutdown. |
| TIMER (Pin 3) | Timer capacitor & CV disable input | CTIMER to GND sets charge duration; tie to VCC for constant-current-only mode (NiMH/NiCd); short to GND to disable C/10. |
| GND (Pin 4) | Power and signal ground reference | Common return for all internal circuits; must be low-impedance connection to minimize sensing error and noise coupling. |
| PROG (Pin 5) | Charge current programming & shutdown control | RPROG to GND sets IBAT = (2.457V × 800Ω)/(RPROG × RSENSE); floating disables IC (ICC ≈ 1mA). |
| DRV (Pin 6) | Pass device drive output | High-impedance source for P-MOSFET gate or PNP base; clamped 6.5V below VCC to protect low-VGS devices. |
| VCC (Pin 7) | Main power input | 4.5–12V supply; powers internal circuitry and drives DRV; requires 1µF ceramic bypass; triggers sleep mode if VCC − VBAT < 54mV. |
| SENSE (Pin 8) | Current sense input | Connects to RSENSE between VCC and SENSE; senses voltage drop to regulate IBAT; referenced to internal 2.457V. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% float voltage regulation | Ensures Li-ion cell remains within JEDEC-specified 4.10V ±0.041V window, preventing overvoltage stress and capacity loss. |
| Automatic trickle preconditioning | Applies 10% of programmed current until VBAT exceeds 2.457V, enabling safe recovery of cells discharged below 2.5V. |
| Programmable C/10 end-of-charge detection | Provides precise, latchable charge termination signal without external comparators-reduces BOM count and layout complexity. |
| 7µA sleep-mode battery drain | Extends shelf life and standby runtime in always-connected portable devices by minimizing parasitic load when no input power is present. |
| External timer capacitor control | Enables field-adjustable charge timeout (e.g., 0.3h to 10h) using standard 0.01µF–1µF capacitors-supports diverse battery chemistries and capacities. |
Applications
| Smartphone Battery Charging | Handheld Medical Device Power |
|---|---|
|
Use Scenario: Recharging 3.7V Li-ion packs in compact smartphones with limited PCB area and strict thermal constraints. IC Role / Device Role / Timing Role: Linear charger controller managing CC/CV profile, C/10 detection, and thermal-safe 500mA charge current. Use Value: Eliminates need for microcontroller-based charging logic while delivering ±1% voltage accuracy and <7µA quiescent drain during standby. |
Use Scenario: Powering portable ECG monitors and glucose meters requiring reliable, low-noise battery charging with long shelf life. IC Role / Device Role / Timing Role: Standalone linear charger providing automatic trickle start, precise 4.1V float, and sleep-mode isolation. Use Value: Ensures regulatory-compliant battery management without firmware development; 7µA sleep current extends unattended operation to >1 year. |
| USB-Powered Peripheral Dock | Industrial Handheld Scanner |
|
Use Scenario: Charging multiple Li-ion batteries in docking stations powered from 5V USB ports with variable load conditions. IC Role / Device Role / Timing Role: Input-flexible charger accepting 4.5–12V, supporting programmable current scaling and UVLO hysteresis. Use Value: Maintains stable 4.1V regulation across wide input range; C/10 output directly drives status LEDs without additional drivers. |
Use Scenario: Ruggedized barcode scanners used in warehouses with frequent deep discharge cycles and temperature extremes. IC Role / Device Role / Timing Role: Robust linear charger with –40°C to 85°C operation, 2.457V trickle threshold, and 10% preconditioning current. Use Value: Recovers cells down to 2.35V safely; ±10% timer accuracy ensures consistent charge duration despite ambient temperature shifts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear battery charger controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1731EMS8-4.2 | Fixed 4.2V float voltage (vs. 4.1V); identical pinout, timing, and current programming architecture. | Targets higher-capacity Li-ion cells requiring JEDEC 4.20V ±0.042V termination; not interchangeable without battery chemistry validation. | Select only if battery datasheet specifies 4.2V nominal float; verify cell voltage tolerance and cycle-life impact before substitution. |
| LTC4053EDD-4.2 | Integrated MOSFET (no external pass device); 4.2V float; 500mA fixed current; smaller 10-lead DFN package. | Lacks programmable current, timer, and trickle mode; suited for cost-sensitive, space-constrained designs with fixed requirements. | Choose when external FET drive complexity must be eliminated and 4.2V/500mA suffices; not suitable for NiMH/NiCd or adjustable current needs. |
Compared with LTC1731EMS8-4.1, the -4.2 variant offers higher termination voltage for greater energy density but reduces margin for aging cells, while the LTC4053EDD-4.2 trades configurability for integration and size-making it viable only where design constraints override flexibility needs.
Availability
LTC1731EMS8-4.1 is available at Aetrix Electronics and suitable for smartphone battery charging, handheld medical device power, USB-powered peripheral docks, and industrial handheld scanners requiring stable component supply across extended production lifecycles.
Supply support for LTC1731EMS8-4.1 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 its precision analog IC portfolio, including battery management solutions trusted in aerospace, medical, and industrial applications.
The LTC1731EMS8-4.1 belongs to Linear's legacy linear battery charger controller family, designed specifically for standalone, microcontroller-free Li-ion charging in space-constrained portable electronics with stringent voltage accuracy and low-quiescent requirements.
FAQ
What is the exact float voltage setpoint of the LTC1731EMS8-4.1?
The LTC1731EMS8-4.1 has a factory-trimmed internal voltage reference that regulates the BAT pin to 4.1V with ±1% accuracy over –40°C to 85°C. This corresponds to a guaranteed range of 4.059V to 4.141V under specified conditions (5V ≤ VCC ≤ 12V), ensuring compliance with JEDEC standards for 4.1V Li-ion cells.
How does the LTC1731EMS8-4.1 handle deeply discharged batteries?
The LTC1731EMS8-4.1 automatically enters trickle charge mode when the BAT pin voltage is below 2.457V, delivering 10% of the programmed full-scale current until the cell voltage rises above this threshold. If the low voltage persists for one quarter of the total timer duration, the IC terminates charging and forces the CHRG pin into high-impedance state.
Can the LTC1731EMS8-4.1 be used with NiMH or NiCd batteries?
Yes-the LTC1731EMS8-4.1 supports constant-current-only mode for NiMH/NiCd by connecting the TIMER pin to VCC, which disables the voltage amplifier, timer, and trickle functions. Charge termination must then be implemented externally (e.g., via ΔV detection or temperature cutoff), as the IC no longer regulates voltage or times out autonomously.
What is the maximum charge current achievable with the LTC1731EMS8-4.1?
The LTC1731EMS8-4.1 supports up to 585mA full-scale charge current when configured with RPROG = 19.6kΩ and RSENSE = 0.2Ω. Higher currents require lower RSENSE values, but thermal limits of the external pass device and PCB layout must be validated-especially given the 200°C/W θJA of the MS8 package.
Does the LTC1731EMS8-4.1 require external compensation components?
No-when used with a P-channel MOSFET as the pass device, the LTC1731EMS8-4.1 is internally compensated and stable without external components. A 10µF capacitor at the BAT pin is recommended for ripple suppression when the battery is disconnected, but no loop compensation network is needed for basic operation.
LTC1731EMS8-4.1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Battery Chemistry:
- Multi-Chemistry
- Number of Cells:
- 1
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- Timer
- Fault Protection:
- -
- Charge Current - Max:
- 500mA
- Battery Pack Voltage:
- 4.1V
- Voltage - Supply (Max):
- 12V
- Interface:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LTC1731EMS8-4.1#TRPBF FAQ
1.How can I place an order for LTC1731EMS8-4.1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1731EMS8-4.1#TRPBF 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 LTC1731EMS8-4.1#TRPBF reliable?
The price and inventory of LTC1731EMS8-4.1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1731EMS8-4.1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1731EMS8-4.1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1731EMS8-4.1#TRPBF transactions.
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LTC1731EMS8-4.1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1731EMS8-4.1#TRPBF 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 LTC1731EMS8-4.1#TRPBF?
For technical support, including LTC1731EMS8-4.1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1731EMS8-4.1#TRPBF requirements.
6.How does Aetrix verify that LTC1731EMS8-4.1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1731EMS8-4.1#TRPBF 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 LTC1731EMS8-4.1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1731EMS8-4.1#TRPBF?
All LTC1731EMS8-4.1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1731EMS8-4.1#TRPBF, 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 LTC1731EMS8-4.1#TRPBF part is unused and in its original packaging.
Return procedure for LTC1731EMS8-4.1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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