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Analog Devices Inc. LTC1729CMS8-8.4#TRPBF
- Part No.:
- LTC1729CMS8-8.4#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1729CMS8-8.4#TRPBF.pdf
- Description:
- IC BATT CHG LI-ION 2CELL 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,044
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Product details
Overview
LTC1729CMS8-8.4#TRPBF from Analog Devices (formerly Linear Technology) is a smart lithium-ion battery charge termination controller for 2-cell (8.4V) systems. 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 LT1505 in portable power management circuits.
For engineers reviewing the LTC1729CMS8-8.4#TRPBF datasheet, LTC1729CMS8-8.4#TRPBF pinout, LTC1729CMS8-8.4#TRPBF application, or LTC1729CMS8-8.4#TRPBF equivalent, key selection criteria include its 8.4V VMAX threshold, ±2.5mV SENSE pin C/10 offset, 10.4V UVLO high threshold, integrated 0.2% precision OVP divider, and MSOP-8 package compatibility with space-constrained cradle chargers and camcorders.
Technical Context
The LTC1729CMS8-8.4#TRPBF implements a state-machine-based control architecture with six internal comparators (COMP1–COMP6), an internally trimmed 131kHz oscillator, and digital timers for preconditioning (1 hr), main charging (3 hr), and filtering (0.86 sec to 4.17 sec). It uses dual-voltage thresholds-VMAX = 9.013V (high-going) and VMIN = 5.4V-to manage battery voltage windows during charge cycles.
Its analog front-end includes a 100µA NTC bias current source, 100µA SENSE sink for C/10 programming, and a 55kΩ internal OVP resistor divider trimmed to ±0.2% accuracy at 2.465V. The IC operates only when VCC ≥ 10.4V (UVLO high), disables charging via open-drain VC pin, and signals status via open-drain STATUS pin with hard pull-down (during charge) and soft 50µA pull-down (post-C/10).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VMAX Threshold | 9.013V high-going threshold triggers overvoltage clamp and pause state; ensures safe 2-cell Li-ion termination at 4.2V/cell. |
| VMIN Threshold | 5.4V low-going threshold initiates trickle-charge preconditioning for deeply discharged batteries (<5.2V). |
| UVLO High | 10.4V minimum VCC required to enable operation; prevents false start-up in low-input or brownout conditions. |
| C/10 Offset | ±2.5mV maximum error on SENSE pin; sets precise 10% full-scale current detection for accurate end-of-charge signaling. |
| OVP Divider Accuracy | ±0.2% internal voltage feedback divider referenced to 2.465V; guarantees stable 8.4V regulation across temperature and unit variance. |
| NTC Bias Current | 100µA constant current source on NTC pin; enables direct interfacing with standard 10kΩ NTC thermistors for 0°C–50°C qualification. |
| Timer2 Duration | 3-hour main charge timer (typical); provides fail-safe termination independent of current sensing, critical for safety-critical applications. |
Pinout & Package
Package: 8-pin MSOP (MS8), 3.0mm × 3.0mm × 0.86mm profile, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OVP (1) | Voltage feedback monitor input | Connects to internal 55kΩ precision divider; senses battery voltage for constant-voltage mode regulation at 8.4V. |
| BAT (2) | Battery voltage monitor and current source | Sources 12mA during preconditioning and 1.3mA during charging; clamped at 4.5V/cell (9V) to prevent overvoltage damage. |
| SENSE (3) | C/10 current detection input | Sinks 100µA to set C/10 threshold; compares against voltage across external sense resistor for end-of-charge detection. |
| GND (4) | Analog ground reference | Common return for all internal comparators, bias currents, and logic; must be low-impedance and separated from power ground if noise-sensitive. |
| NTC (5) | Thermistor monitoring input | Accepts 10kΩ NTC; 100µA bias generates 2.79V at 0°C and 0.405V at 50°C; triggers HOLD mode outside qualified range. |
| STATUS (6) | Open-drain charge status output | Pulled low during charge; transitions to 50µA soft pull-down after C/10 detection; floats high at timer expiry or power removal. |
| VC (7) | Open-drain charger enable/disable | Open-circuit enables external charger; pulled low disables charger during HOLD, RESET, DONE, or PAUSE states. |
| VCC (8) | Supply input | Operates from 12V to 30V; UVLO activates at 10.4V (high) / 9.6V (low); internal disconnect removes OVP divider load below UVLO. |
Key Features
| Feature | Design Value |
|---|---|
| Trickle-charge preconditioning | Automatically activates 12mA current source when VBAT < 5.4V, preventing lithium plating on deeply discharged cells. |
| Temperature-qualified charging | Uses NTC pin with 0.2V reset and 0.405V/2.79V hold thresholds to enforce 0°C–50°C operational window per JEITA standards. |
| Two-stage termination logic | Combines C/10 current detection (with 3-second digital filter) and 3-hour absolute time-out for redundant safety compliance. |
| Automatic battery presence detection | Detects battery insertion/removal via BAT pin voltage ramp; resets timers on new battery install without microcontroller intervention. |
| Integrated OVP precision divider | Factory-trimmed 0.2% resistor network referenced to 2.465V eliminates need for external feedback resistors in 8.4V systems. |
Applications
| Cellular Phone Cradle Charger | Camcorder Dual-Cell Pack |
|---|---|
Use Scenario: Wall-powered desktop charger for removable 2-cell Li-ion battery packs in legacy smartphones. IC Role / Device Role / Timing Role: Charge termination controller coordinating with LT1512 SEPIC charger; manages precondition, CV phase, and safety cutoff. Use Value: Enables compact, self-contained charging with no MCU dependency-reduces BOM count and firmware overhead. | Use Scenario: Integrated battery management in consumer-grade camcorders requiring field-replaceable 8.4V packs. IC Role / Device Role / Timing Role: Smart termination supervisor enforcing JEITA-compliant thermal limits and 3-hour max charge duration. Use Value: Prevents thermal runaway during high-current charging by halting charge if NTC voltage falls outside 0.405V–2.79V range. |
| Industrial Handheld Scanner | Medical Portable Monitor |
Use Scenario: Ruggedized handheld scanner with hot-swappable 2-cell battery and USB/DC input flexibility. IC Role / Device Role / Timing Role: Battery interface controller detecting battery presence, enabling fast-charge sequencing, and signaling status to host MCU via STATUS pin. Use Value: STATUS pin's three-state behavior (hard pull-down → soft 50µA → high-Z) allows single GPIO to distinguish charging, C/10, and done states. | Use Scenario: Battery-backed vital signs monitor requiring certified charge safety and long-term reliability. IC Role / Device Role / Timing Role: Safety-critical termination element verifying both voltage (VMAX/VMIN) and current (C/10) thresholds before declaring charge complete. Use Value: Dual-termination logic satisfies IEC 62368-1 requirements by providing independent time-based and current-based cutoff mechanisms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar charge termination controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1729CMS8-8.2#TRPBF | Configured for 8.2V (4.1V/cell) termination; VMAX = 8.5V (high-going), VMIN = 5.1V; identical pinout and timing. | Used in older 2-cell Li-ion designs specifying 4.1V/cell nominal; not suitable for 4.2V/cell chemistries requiring 8.4V final voltage. | Select only if battery pack datasheet specifies 4.1V/cell charge voltage; verify OVP divider trim matches target VMAX. |
| BQ29700DRVR | TI standalone Li-ion charge supervisor; supports 1–3 cells; includes integrated LDO, but lacks built-in C/10 detection circuitry. | Requires external current-sense amplifier and comparator for C/10; better suited for multi-cell systems needing flexible cell-count configuration. | Choose when system requires programmable cell count or integrated bias supply; avoid if C/10 detection must be self-contained without external components. |
Compared with LTC1729CMS8-8.4#TRPBF, the LTC1729CMS8-8.2#TRPBF offers identical functionality at a lower voltage threshold, while the BQ29700DRVR trades C/10 integration for broader cell-count support and added power management features-making it less drop-in but more scalable for evolving platforms.
Availability
LTC1729CMS8-8.4#TRPBF is available at Aetrix Electronics and suitable for cradle chargers, camcorders, industrial handheld scanners, and medical portable monitors requiring stable component supply, long-lifecycle support, and automotive-grade reliability validation.
Supply support for LTC1729CMS8-8.4#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, documentation, and manufacturing continuity for the LTC portfolio.
The LTC1729 series belongs to Linear's precision battery management IC family, designed specifically for cost-sensitive, space-constrained portable devices requiring robust, autonomous Li-ion charge termination without microcontroller supervision.
FAQ
What is the primary function of the LTC1729CMS8-8.4#TRPBF in a battery charging system?
The LTC1729CMS8-8.4#TRPBF serves as a dedicated charge termination controller for 2-cell (8.4V) lithium-ion batteries. Its core function is to autonomously stop charging after either three hours or when the charge current drops below C/10-whichever occurs first-while also managing trickle preconditioning, temperature qualification, and battery presence detection. It works in conjunction with external DC/DC chargers like the LT1512 or LT1505, not as a standalone charger.
How does the LTC1729CMS8-8.4#TRPBF handle overvoltage protection during charging?
The LTC1729CMS8-8.4#TRPBF implements overvoltage protection using its OVP pin (Pin 1) and internal 55kΩ precision resistor divider, which is trimmed to ±0.2% accuracy at 2.465V. When the battery voltage exceeds 9.013V (VMAX high-going threshold), comparator COMP2 triggers a clamp action that pulls the VC pin low, disabling the external charger. This prevents overcharging and protects against transients caused by battery protection circuit disconnection during constant-current mode.
Can the LTC1729CMS8-8.4#TRPBF be used with a single-cell 4.2V battery?
No-the LTC1729CMS8-8.4#TRPBF is factory-configured for 2-cell (8.4V) systems only. Its internal OVP divider, VMAX (9.013V), VMIN (5.4V), and UVLO thresholds (10.4V high) are optimized for 4.2V/cell chemistry. For single-cell 4.2V applications, use the pin-compatible LTC1729CMS8-4.2#TRPBF, which has matching MSOP-8 packaging but different internal trimming and voltage thresholds.
What happens to the STATUS pin of the LTC1729CMS8-8.4#TRPBF during different charge states?
The STATUS pin of the LTC1729CMS8-8.4#TRPBF behaves distinctly across states: during active charging, it is hard-pulled low by an internal NMOS; once C/10 is detected for ≥3 seconds, the hard pull-down turns off and a 50µA soft pull-down remains active; upon 3-hour timer expiry or input removal, the pin goes high-impedance. This three-state behavior enables simple microcontroller GPIO monitoring without additional circuitry.
Is an NTC thermistor mandatory for proper operation of the LTC1729CMS8-8.4#TRPBF?
Yes-an NTC thermistor (or 10kΩ resistor if thermal qualification is disabled) must be connected to the NTC pin (Pin 5). Leaving the pin floating violates the device's operating conditions and may cause unpredictable behavior. The 100µA internal bias current requires a defined load to generate valid voltage thresholds (0.2V reset, 0.405V hot hold, 2.79V cold hold); absence of this load disrupts thermal safety enforcement and can disable charge initiation.
LTC1729CMS8-8.4#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:
- 8.4V
- Voltage - Supply (Max):
- 28V
- Interface:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LTC1729CMS8-8.4#TRPBF FAQ
1.How can I place an order for LTC1729CMS8-8.4#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1729CMS8-8.4#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 LTC1729CMS8-8.4#TRPBF reliable?
The price and inventory of LTC1729CMS8-8.4#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1729CMS8-8.4#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1729CMS8-8.4#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1729CMS8-8.4#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1729CMS8-8.4#TRPBF?
LTC1729CMS8-8.4#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1729CMS8-8.4#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 LTC1729CMS8-8.4#TRPBF?
For technical support, including LTC1729CMS8-8.4#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1729CMS8-8.4#TRPBF requirements.
6.How does Aetrix verify that LTC1729CMS8-8.4#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1729CMS8-8.4#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 LTC1729CMS8-8.4#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1729CMS8-8.4#TRPBF?
All LTC1729CMS8-8.4#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1729CMS8-8.4#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 LTC1729CMS8-8.4#TRPBF part is unused and in its original packaging.
Return procedure for LTC1729CMS8-8.4#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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