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Analog Devices Inc. LTC1729CS8-8.4#PBF
- Part No.:
- LTC1729CS8-8.4#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1729CS8-8.4#PBF.pdf
- Description:
- IC BATT CHG LI-ION 2CELL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,748
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Product details
Overview
LTC1729CS8-8.4#PBF 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 LTC1729CS8-8.4#PBF datasheet, LTC1729CS8-8.4#PBF pinout, LTC1729CS8-8.4#PBF application, or LTC1729CS8-8.4#PBF equivalent, key selection criteria include its 8.4V battery voltage threshold, integrated VMAX/VMIN comparators, NTC-based thermal lockout, open-drain VC and STATUS outputs, and compatibility with high-current external chargers.
Technical Context
The LTC1729CS8-8.4#PBF implements a state-machine-driven termination logic with six internal comparators (COMP1–COMP6), a 131kHz trimmed oscillator, and 25-bit counter for timing control. Its architecture supports dual-mode operation: trickle-charge preconditioning (12mA, 1-hour timeout) for deeply discharged batteries (<5.4V), followed by full-charge mode (1.3mA BAT sink, 3-hour timeout).
It integrates precision analog monitoring: OVP feedback divider trimmed to ±0.2% for 8.4V systems (2.465V at OVP pin), VMAX = 9.013V (high-going), VMIN = 5.4V (low-going), and NTC bias current of 100µA enabling cold/hot hold thresholds at 2.79V and 0.405V respectively - all specified over 0°C to 70°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBAT Thresholds | VMAX = 9.013V (high-going), VMIN = 5.4V - defines valid charging window for 2-cell Li-ion; clamps BAT above 9V to prevent overvoltage |
| NTC Interface | 100µA bias current; cold hold at 2.79V (≈0°C), hot hold at 0.405V (≈50°C); reset at <0.2V - enables safe thermal qualification without external circuitry |
| Termination Logic | 3-hour timer + C/10 detection (3-second digital filter); STATUS pin transitions from hard pull-down to 50µA soft pull-down upon C/10 - supports microprocessor-readable three-state status |
| Supply Range | VCC UVLO: 9.6V (typ), 10.4V (max); operates from 12V–28V input - matches 2-cell charger supply rails and prevents false start during brownout |
| Pin Drive Capability | VC pin: open-drain, 1mA sink, 0.6V low; STATUS pin: open-drain, 3mA sink, 0.9V low - directly controls external charger enable and drives LEDs or MCU inputs |
| Accuracy | Internal voltage feedback divider: ±0.2% - ensures precise 8.4V termination reference across temperature and unit variation |
Pinout & Package
Package: 8-lead plastic SO (S8), 0.150" narrow body, RoHS-compliant, rated for 0°C to 70°C operation. Thermal resistance θJA = 200°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OVP (1) | Voltage feedback monitor input | Connects to precision resistor divider from battery; triggers constant-voltage mode termination when 2.465V reached - calibrated for 8.4V system |
| BAT (2) | Battery voltage sensing & current source | Sinks 12mA (precondition) or 1.3mA (charge); clamped at 9V; detects battery presence via voltage ramp on disconnect |
| SENSE (3) | C/10 current threshold input | Sinks 100µA; develops offset voltage across external sense resistor to set C/10 trip point - programmable via RSENSE |
| GND (4) | Analog ground reference | Common return for all internal comparators and bias currents; must be low-impedance path to minimize noise coupling |
| NTC (5) | Thermistor monitoring input | 100µA bias current enables direct 10kΩ NTC interface; holds or resets state machine based on voltage thresholds |
| STATUS (6) | Open-drain charge status output | Pulled low during charge; transitions to 50µA soft pull-down at C/10; floats after 3-hour timeout - supports LED or MCU status decoding |
| VC (7) | Open-drain charger enable/disable | Open-circuit enables external charger; pulled low disables charger - used for termination, thermal hold, or reset |
| VCC (8) | Supply input | Accepts 12V–28V; includes undervoltage lockout (9.6V typ); powers internal logic and bias circuits |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3-hour termination timer | Hardware-based counter eliminates need for external MCU timing; self-tested 25-bit chain ensures reliability in safety-critical charging |
| Programmable C/10 detection | 100µA SENSE pin current allows user-defined current threshold via single external resistor - enables accurate end-of-charge detection independent of charger IC |
| Automatic battery presence detection | Detects battery insertion/removal via BAT pin voltage ramp and VMAX comparator - restarts timers automatically without host intervention |
| Thermal qualification with hold mode | NTC interface locks state machine and disables charging if outside 0°C–50°C range - prevents unsafe charging without requiring external logic |
| Trickle-charge preconditioning | 12mA constant current applied when VBAT < 5.4V, with 1-hour timeout - safely recovers deeply discharged 2-cell packs before full-rate charging |
Applications
| Cellular Phones | PDAs |
|---|---|
Use Scenario: Dual-cell Li-ion battery charging in compact handheld devices with space-constrained PCB layouts. IC Role / Device Role / Timing Role: Charge termination controller coordinating with LT1512 SEPIC charger; manages C/10 detection, thermal hold, and 3-hour timeout. Use Value: Enables reliable, autonomous charging without host processor involvement - reduces firmware complexity and BOM count. | Use Scenario: Portable data assistant with removable 2-cell battery pack requiring safe, temperature-aware charging. IC Role / Device Role / Timing Role: Battery interface supervisor detecting pack insertion, validating temperature via NTC, and enforcing charge limits. Use Value: Prevents charging outside 0°C–50°C using only internal comparators and 100µA NTC bias - no external ADC or thermal IC needed. |
| Cradle Chargers | Camcorders |
Use Scenario: Desktop cradle charger supporting multiple 2-cell battery configurations with varying capacity. IC Role / Device Role / Timing Role: Universal termination engine interfacing with LT1505 (4A step-down) to adapt to different battery Ah ratings via C/10 resistor. Use Value: Single-footprint solution scales across battery capacities - eliminates redesign when upgrading from 1500mAh to 3000mAh cells. | Use Scenario: High-power camcorder with fast-charging requirement and thermal protection during extended recording sessions. IC Role / Device Role / Timing Role: Safety monitor asserting VC low during thermal hold (NTC <0.405V), halting charge while preserving STATUS indication for UI feedback. Use Value: Maintains real-time status visibility (via STATUS pin states) even during thermal interruption - improves user experience and diagnostics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar charge termination controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1729CMS8-8.4#PBF | Same functionality and electrical specs; MSOP-8 package (3mm × 3mm) vs SO-8 (4.9mm × 3.9mm) - 40% smaller footprint, higher thermal resistance (θJA = 200°C/W vs 150°C/W) | Preferred for ultra-compact designs where board area is critical; less suitable for high-ambient industrial environments due to thermal derating | Select LTC1729CMS8-8.4#PBF when PCB space is constrained and thermal margin permits; otherwise retain SO-8 for easier rework and better heat dissipation. |
| LTC4065EDD-4.2#TRMPBF | Integrated linear charger (not termination-only); fixed 4.2V single-cell output; no NTC support or C/10 detection; 12-bump DFN package | Only suitable for low-power, single-cell applications; lacks 2-cell capability, thermal qualification, and external charger interface | LTC4065EDD-4.2#TRMPBF is not a functional substitute - use only for simple 1-cell USB-powered devices without thermal or multi-cell requirements. |
Compared with LTC1729CMS8-8.4#PBF, the LTC1729CS8-8.4#PBF offers larger pad geometry for improved manufacturability and thermal performance in 2-cell cradle or camcorder applications, while LTC4065EDD-4.2#TRMPBF serves entirely different use cases with no overlap in voltage range, cell count, or feature set.
Availability
LTC1729CS8-8.4#PBF is available at Aetrix Electronics and suitable for cellular phones, PDAs, and cradle chargers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for LTC1729CS8-8.4#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 LTC1729CS8-8.4#PBF belongs to Linear's battery management IC family, designed specifically for autonomous, high-reliability termination control in multi-cell Li-ion charging systems where external MCU supervision is impractical or undesirable.
FAQ
What is the primary function of the LTC1729CS8-8.4#PBF in a battery charging system?
The LTC1729CS8-8.4#PBF serves as a dedicated charge termination controller for 2-cell (8.4V) lithium-ion batteries. Its core function is to autonomously stop charging after three hours or when the current drops below C/10, using internal comparators and timers - eliminating reliance on host processor control. It also performs preconditioning, thermal qualification, and battery presence detection.
How does the LTC1729CS8-8.4#PBF interface with external chargers like the LT1512 or LT1505?
The LTC1729CS8-8.4#PBF interfaces with external chargers using six signals: VC (charger enable/disable), STATUS (charge state indicator), OVP (voltage feedback), BAT (battery sense), SENSE (current threshold), and NTC (thermal sense). Connecting these pins to compatible LT chargers requires no additional logic - the LTC1729CS8-8.4#PBF directly controls charger operation via open-drain outputs and analog monitoring inputs.
What are the absolute maximum ratings for the VCC and BAT pins of the LTC1729CS8-8.4#PBF?
The LTC1729CS8-8.4#PBF specifies VCC absolute maximum at 30V and BAT pin rating at –0.3V to 15V. These limits ensure robust operation when interfacing with high-voltage step-down chargers or during transient events such as battery pack protection switch opening. Exceeding these values risks permanent damage to internal ESD structures and comparator inputs.
Can the LTC1729CS8-8.4#PBF be used with a single-cell 4.2V battery?
No - the LTC1729CS8-8.4#PBF is factory-trimmed for 8.4V (2-cell) systems, with internal OVP divider calibrated to 2.465V reference for that voltage. Using it with a 4.2V battery would result in premature termination at ~4.1V and incorrect VMAX/VMIN thresholds. For single-cell applications, use LTC1729CS8-4.2#PBF instead.
Does the LTC1729CS8-8.4#PBF require external components to operate, and if so, what are the minimum required?
Yes - the LTC1729CS8-8.4#PBF requires at minimum: a 10kΩ NTC thermistor (or resistor) on NTC pin, a voltage divider from battery to OVP pin, a current-sense resistor tied to SENSE pin, and pull-up resistors on STATUS and VC pins. No external clock or timing capacitors are needed - all timing is generated internally via the 131kHz oscillator and digital counters.
LTC1729CS8-8.4#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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-SO
LTC1729CS8-8.4#PBF FAQ
1.How can I place an order for LTC1729CS8-8.4#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1729CS8-8.4#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 LTC1729CS8-8.4#PBF reliable?
The price and inventory of LTC1729CS8-8.4#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1729CS8-8.4#PBF is usually 5 days.
3.What payment methods are accepted for LTC1729CS8-8.4#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1729CS8-8.4#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1729CS8-8.4#PBF?
LTC1729CS8-8.4#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1729CS8-8.4#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 LTC1729CS8-8.4#PBF?
For technical support, including LTC1729CS8-8.4#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1729CS8-8.4#PBF requirements.
6.How does Aetrix verify that LTC1729CS8-8.4#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1729CS8-8.4#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 LTC1729CS8-8.4#PBF meets industry standards.
7.What is the process for return or replacement of LTC1729CS8-8.4#PBF?
All LTC1729CS8-8.4#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1729CS8-8.4#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 LTC1729CS8-8.4#PBF part is unused and in its original packaging.
Return procedure for LTC1729CS8-8.4#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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