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Analog Devices Inc. LTC1729CMS8-8.2#TRPBF
- Part No.:
- LTC1729CMS8-8.2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1729CMS8-8.2#TRPBF.pdf
- Description:
- IC BATT CHG LI-ION 2CELL 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,471
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Product details
Overview
LTC1729CMS8-8.2#TRPBF from Analog Devices (formerly Linear Technology) is a smart lithium-ion battery charge termination controller for 2-cell (8.2V nominal) applications. It provides C/10 current detection, 3-hour time-out termination, trickle-charge preconditioning below 5.4V, temperature qualification via NTC thermistor (0°C–50°C), and automatic battery/charger presence detection. It interfaces with step-down or SEPIC chargers such as LT1512 and LT1513 in portable power systems.
For engineers reviewing the LTC1729CMS8-8.2#TRPBF datasheet, LTC1729CMS8-8.2#TRPBF pinout, LTC1729CMS8-8.2#TRPBF application, or LTC1729CMS8-8.2#TRPBF equivalent, key selection criteria include its 8.2V battery voltage threshold, MSOP-8 package compatibility, NTC-based thermal safety enforcement, and dual-termination logic (C/10 + timer) for Li-ion charging control in space-constrained cradle chargers and camcorders.
Technical Context
The LTC1729CMS8-8.2#TRPBF implements a state-machine-driven termination architecture with six internal comparators, UVLO (9.6V typ), and precision 0.2% OVP feedback divider. Its logic block integrates three independent timers: TIMER1 (1 hr trickle), TIMER2 (3 hr main charge), and digital filters (TIMER3/TIMER4) for VMAX and C/10 detection stability.
It operates in four distinct functional states-Precondition, Charger "ON", Pause, and Done-with hard/soft pull-down on STATUS and open-drain VC output to disable external chargers. The NTC pin bias current (100 µA) enables direct 10 kΩ thermistor interfacing, while SENSE pin sinking 100 µA sets C/10 threshold via external sense resistor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBAT Threshold (High) | 8.5V to 9.5V - precise clamp and termination trigger for 2-cell Li-ion packs at 4.25V/cell |
| VBAT Threshold (Low) | 4.9V to 5.5V - enables trickle preconditioning when cell voltage drops below ~2.45V/cell |
| NTC Voltage Range | 0.160V–0.240V (reset), 0.380V–0.510V (hot hold), 2.10V–2.90V (cold hold) - supports 0°C–50°C thermal qualification |
| Main Charge Timer | 2.61–3.55 hours - fixed-duration termination for constant-voltage phase, preventing overcharge |
| C/10 Detection Filter | 3.055–4.17 sec - digital filter ensures stable current-threshold recognition before status transition |
| Supply UVLO | 8.5V–10.5V (low), 9.5V–11.4V (high) - prevents operation outside safe input range for 2-cell charger systems |
| OVP Pin Reference | 2.465V ±0.2% - trimmed internal divider enables accurate 8.2V or 8.4V battery voltage monitoring |
Pinout & Package
Package: 8-pin MSOP (MS8), 3.0 mm × 3.0 mm × 0.85 mm, θJA = 200°C/W, RoHS-compliant, tape-and-reel (#TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OVP (1) | Voltage feedback monitor input | Connects to precision resistive divider from battery; triggers termination when >2.465V (i.e., VBAT >8.2V) |
| BAT (2) | Battery voltage sensing & current sourcing | Sources 12 mA during trickle, 1.3 mA during charge; clamped at 9.0V max; enables battery presence detection |
| SENSE (3) | C/10 current threshold reference | Sinks 100 µA; voltage drop across external sense resistor sets C/10 trip point (e.g., 20 mV = 0.2 Ω × 100 mA) |
| GND (4) | Analog ground reference | Common return for all internal comparators, timers, and bias currents; must be low-impedance |
| NTC (5) | Thermistor interface input | 100 µA bias current enables direct 10 kΩ NTC connection; detects cold/hot conditions and forces Hold/Reset |
| STATUS (6) | Open-drain charge status indicator | Pulled low during charge; transitions to 50 µA soft pull-down at C/10; floats high at timer expiry or battery removal |
| VC (7) | Charger enable/disable control | Open-drain output; pulled low to disable external charger IC (e.g., LT1512); active during Hold/Reset/Pause/Done |
| VCC (8) | Input supply pin | Accepts 9–30 V; UVLO disables IC below ~9.6 V; powers internal logic, comparators, and bias circuits |
Key Features
| Feature | Design Value |
|---|---|
| Trickle-charge preconditioning | Automatically activates below 5.4V (VMIN), sourcing 12 mA for up to 1 hour to safely recover deeply discharged cells |
| Dual-termination logic | Simultaneous C/10 current detection (with 3-second digital filter) and 3-hour timer ensures robust overcharge protection |
| Integrated thermal safety | NTC monitoring with cold/hot hold modes halts charging outside 0°C–50°C without external circuitry |
| Automatic battery detection | Detects battery insertion/removal via BAT pin voltage ramp; resets timers and reinitializes state machine on new battery |
| Precision voltage reference | 0.2% trimmed internal divider delivers 2.465V at OVP pin for accurate 8.2V/8.4V battery voltage regulation |
Applications
| Cellular Phone Cradle Chargers | Camcorder Docking Stations |
|---|---|
|
Use Scenario: Wall-powered dock that charges removable Li-ion battery packs during standby or playback. IC Role / Device Role / Timing Role: LTC1729CMS8-8.2#TRPBF acts as termination supervisor, coordinating with LT1513 SEPIC charger to halt charge after 3 hours or at C/10 current. Use Value: Prevents overcharge-induced swelling in compact 2-cell packs while enabling LED status feedback via STATUS pin's dual pull-down behavior. |
Use Scenario: Portable video recorder with hot-swap battery support and thermal monitoring during extended field recording. IC Role / Device Role / Timing Role: LTC1729CMS8-8.2#TRPBF monitors NTC voltage and BAT voltage to enforce 0°C–50°C charging window and detect pack removal mid-cycle. Use Value: Eliminates need for microcontroller-based charge management; reduces BOM count by integrating timer, comparator, and state logic in one MSOP-8 device. |
| Industrial Handheld Scanners | Medical Portable Monitors |
|
Use Scenario: Ruggedized barcode scanner with replaceable 2-cell Li-ion battery and USB/DC input flexibility. IC Role / Device Role / Timing Role: LTC1729CMS8-8.2#TRPBF provides UVLO-protected start-up, trickle preconditioning for infrequently used batteries, and fail-safe termination. Use Value: Ensures reliable first-charge recovery of stored batteries and meets IEC 62133 safety requirements via hardware-enforced thermal and time limits. |
Use Scenario: Battery-backed vital signs monitor requiring certified, maintenance-free charging for clinical reuse. IC Role / Device Role / Timing Role: LTC1729CMS8-8.2#TRPBF serves as standalone safety layer between charger IC and battery, independently verifying voltage, current, and temperature. Use Value: Enables regulatory compliance (UL/IEC) with deterministic, analog-based termination-no firmware validation required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar lithium-ion charge termination applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1729CMS8-8.4#TRPBF | Configured for 8.4V battery threshold (4.2V/cell); identical pinout, timing, and feature set | Used where battery packs specify 4.2V/cell nominal; not interchangeable without adjusting OVP divider | Select only if target battery requires 4.2V/cell regulation; otherwise, LTC1729CMS8-8.2#TRPBF matches 4.1V/cell packs |
| LTC4066EMS8#TRPBF | Integrated linear charger + termination; no external charger IC needed; different topology (linear vs. switching) | Lower power, single-cell only; unsuitable for 2-cell or high-current (>1A) applications | Choose for ultra-compact, low-power devices; avoid when using step-down/SEPIC chargers like LT1512/LT1513 |
Compared with LTC1729CMS8-8.4#TRPBF, the LTC1729CMS8-8.2#TRPBF offers tighter voltage matching for 4.1V/cell chemistries, while LTC4066EMS8#TRPBF eliminates external charger complexity but sacrifices efficiency and 2-cell capability-making LTC1729CMS8-8.2#TRPBF optimal for high-efficiency, thermally constrained dual-cell systems.
Availability
LTC1729CMS8-8.2#TRPBF is available at Aetrix Electronics and suitable for cellular phone cradle chargers, camcorder docking stations, and industrial handheld scanners requiring stable component supply, long-lifecycle support, and guaranteed RoHS-compliant manufacturing.
Supply support for LTC1729CMS8-8.2#TRPBF 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, datasheet archives, and application engineering for legacy Linear parts including the LTC1729 series.
The LTC1729 series was designed specifically for hardware-based, microcontroller-free Li-ion charge termination in portable consumer and industrial equipment-emphasizing reliability, thermal safety, and minimal external component count.
FAQ
What is the primary function of the LTC1729CMS8-8.2#TRPBF in a battery charging system?
The LTC1729CMS8-8.2#TRPBF serves as a dedicated hardware charge termination controller for 2-cell lithium-ion batteries. Its core function is to autonomously stop external switch-mode chargers (e.g., LT1512) after either three hours of constant-voltage charging or when charge current falls below C/10-without requiring software intervention. It also manages trickle preconditioning, thermal qualification, and battery presence detection.
How does the LTC1729CMS8-8.2#TRPBF interface with an external charger IC like the LT1512?
The LTC1729CMS8-8.2#TRPBF interfaces with the LT1512 using just two signals: VC (pin 7) and STATUS (pin 6). The open-drain VC pin pulls low to disable the LT1512's gate drive when termination conditions are met. STATUS provides real-time charge status to LEDs or microcontrollers. No communication protocol or additional logic is needed-the integration requires only six interconnect pins total per the datasheet.
Can the LTC1729CMS8-8.2#TRPBF be used with a 4.1V/cell battery pack?
No-the LTC1729CMS8-8.2#TRPBF is factory-trimmed for 8.2V total (4.1V/cell) battery voltage monitoring and cannot be reconfigured for other thresholds. Its internal 0.2% precision divider fixes the OVP reference at 2.465V, which corresponds exclusively to 8.2V at the BAT pin. For 4.2V/cell packs, LTC1729CMS8-8.4#TRPBF must be used instead.
What happens if the NTC thermistor is omitted from the LTC1729CMS8-8.2#TRPBF circuit?
The NTC pin must never be left floating. If thermal monitoring is not required, a 10 kΩ pull-up resistor to VCC must be substituted per the datasheet. Omitting both thermistor and resistor causes undefined behavior: the NTC pin voltage may drift into reset or hold ranges, disabling charging unpredictably. The LTC1729CMS8-8.2#TRPBF will not operate reliably without a defined DC path at NTC.
Does the LTC1729CMS8-8.2#TRPBF support automatic restart after battery replacement?
Yes-the LTC1729CMS8-8.2#TRPBF detects battery removal via BAT pin voltage rise above VMAX and transitions to Pause or No Bat state. When a new battery is inserted and BAT remains below VMAX for ≥1 second, it automatically reinitializes the state machine, clears all timers, and begins a fresh charge cycle-including preconditioning if voltage is below 5.4V. This behavior is fully autonomous and requires no host intervention.
LTC1729CMS8-8.2#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:
- Lithium Ion
- Number of Cells:
- 2
- Current - Charging:
- -
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- -
- Battery Pack Voltage:
- 8.2V
- Voltage - Supply (Max):
- 28V
- Interface:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LTC1729CMS8-8.2#TRPBF FAQ
1.How can I place an order for LTC1729CMS8-8.2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1729CMS8-8.2#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 LTC1729CMS8-8.2#TRPBF reliable?
The price and inventory of LTC1729CMS8-8.2#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1729CMS8-8.2#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1729CMS8-8.2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1729CMS8-8.2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1729CMS8-8.2#TRPBF?
LTC1729CMS8-8.2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1729CMS8-8.2#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 LTC1729CMS8-8.2#TRPBF?
For technical support, including LTC1729CMS8-8.2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1729CMS8-8.2#TRPBF requirements.
6.How does Aetrix verify that LTC1729CMS8-8.2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1729CMS8-8.2#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 LTC1729CMS8-8.2#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1729CMS8-8.2#TRPBF?
All LTC1729CMS8-8.2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1729CMS8-8.2#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 LTC1729CMS8-8.2#TRPBF part is unused and in its original packaging.
Return procedure for LTC1729CMS8-8.2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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