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Analog Devices Inc. LT1769IFE#PBF
- Part No.:
- LT1769IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1769IFE#PBF.pdf
- Description:
- IC BATT CHG MULTI-CHEM 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,024
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Product details
Overview
LT1769IFE#PBF from Analog Devices (formerly Linear Technology) is a constant-current/constant-voltage 2A switching battery charger IC for Li-ion, NiMH, and NiCd batteries. It integrates a 3A peak internal NPN switch, delivers ±5% charge current accuracy via resistor or DAC programming, maintains 0.5% reference voltage accuracy for precise CV-mode float regulation, and supports input adapter current limiting to enable simultaneous system operation and charging. It is used in portable medical devices, industrial handhelds, and ruggedized communications equipment requiring reliable single-chip battery management.
For engineers reviewing the LT1769IFE#PBF datasheet, LT1769IFE#PBF pinout, LT1769IFE#PBF application, or LT1769IFE#PBF equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternative parts with documented functional differences, and supply-ready availability details - all grounded in the official LT1769FA datasheet and Analog Devices product documentation.
Technical Context
The LT1769IFE#PBF implements a current-mode PWM buck topology with three independent control loops: one for battery charge current (via PROG pin and CA1 amplifier), one for battery voltage regulation (via OVP pin and VA amplifier with 2.465V reference), and one for input adapter current limiting (via CLP/CLN pins and CL1 amplifier). Its 200kHz fixed-frequency oscillator enables compact magnetics and low EMI.
It features ground-referenced current sensing (BAT/SENSE pins support high-side or low-side placement), automatic shutdown when VCC drops below 7V (UV pin threshold), and sleep-mode reverse battery drain of only 3µA. The exposed-pad TSSOP-20 package provides thermal resistance of 35°C/W, enabling full 2A continuous operation with proper PCB copper area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Continuous Charge Current | 2A DC - supports fast charging of 2–3S Li-ion packs or multi-cell NiMH/NiCd stacks without external pass devices. |
| Reference Voltage Accuracy | ±0.5% at 25°C - ensures ≤±42mV error on 8.4V Li-ion float voltage, meeting JEITA-compliant CV tolerance. |
| Charge Current Accuracy | ±5% - achieved via resistor-programmed IPROG path and CA1 transconductance stability across temperature. |
| Switching Frequency | 200kHz typical - balances efficiency (≥94% at 2A, VIN=16.5V, VBAT=8.4V) and inductor size (22µH standard). |
| Input Voltage Range | 8V to 28V - accommodates wide-range AC adapters (e.g., 12V/15V/19V wall bricks) while maintaining ≥3V headroom over VBAT. |
| Reverse Battery Drain | 3µA typical - enables >1-year shelf life for battery-backed systems when adapter is disconnected. |
| Undervoltage Lockout | 6.7V rising threshold with 0.5V hysteresis - prevents unstable operation during brownout and enables clean startup sequencing. |
Pinout & Package
LT1769IFE#PBF uses a 20-lead plastic TSSOP package with exposed pad (FE package), rated for θJA = 35°C/W. The bottom metal plate is fused to internal ground and must be soldered to a PCB ground plane for thermal performance.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch Output | Drives external Schottky catch diode; connects to inductor node; requires short trace to GND to minimize ringing and EMI. |
| BOOST (Pin 2) | Bootstrap Driver | Supplies gate drive to internal NPN switch; must be biased ≥3V above VCC for low RON (0.15Ω typical) and minimal conduction loss. |
| UV (Pin 3) | Undervoltage Input | Monitors adapter input; triggers shutdown at 6.7V; requires pull-down resistor to limit reverse battery current to 3µA when adapter removed. |
| GND (Pins 4,5,14,20) | Ground Terminal | Multiple dedicated GND pins tied to exposed pad; must connect to large PCB copper pour for heat sinking and low-noise return path. |
| OVP (Pin 6) | Voltage Sense Input | Connects to resistor divider from battery; compares against 2.465V reference to regulate CV mode; bias current <3nA minimizes divider error. |
| CLP / CLN (Pins 8,7) | Adapter Current Sense Inputs | Differential inputs for RS4 sense resistor; 100mV threshold enables analog current limiting without digital intervention or firmware. |
| PROG (Pin 16) | Charge Current Programming | Accepts resistor or DAC-sourced current (IPROG); sets IBAT = (2.465V/RPROG) × (RS2/RS1); shorting to GND disables charging. |
| VC (Pin 15) | Current Mode Control | Inner-loop PWM control voltage; 0.7V threshold starts switching; soft-start ramp controlled by 0.33µF capacitor; pulling low forces shutdown. |
| BAT / SENSE (Pins 12,10) | Battery Current Sense | Differential inputs supporting high-side or low-side sensing; eliminates need for ground-referenced shunt; common-mode range extends to –0.25V. |
Key Features
| Feature | Design Value |
|---|---|
| Three-Loop Regulation | Simultaneous CC/CV battery charging + input adapter current limiting - eliminates need for external microcontroller-based load balancing. |
| Adaptive Adapter Current Limit | Analog closed-loop reduction of charge current when adapter output exceeds preset limit - enables concurrent system operation and charging without firmware coordination. |
| Low Reverse Battery Drain | 3µA sleep-mode current - preserves battery capacity during storage or field downtime without requiring mechanical disconnect switches. |
| Flexible Current Sensing | Supports BAT/SENSE connection at either battery terminal - simplifies PCB layout and avoids ground loop issues in systems with shared battery/system grounds. |
| Thermal-Efficient Exposed-Pad Package | TSSOP-20 with soldered exposed pad achieves 35°C/W θJA - sustains 2A continuous charging in compact industrial enclosures without forced air. |
Applications
| Portable Medical Monitors | Industrial Handheld Terminals |
|---|---|
|
Use Scenario: Rechargeable Li-ion powered vital signs monitor operating continuously in clinical environments with hot-swap AC adapter support. IC Role / Device Role / Timing Role: Primary battery charger managing CC/CV profile and dynamically throttling charge current when adapter cannot supply both system load and full charge rate. Use Value: Enables uninterrupted operation during charging - no system reboot or data loss when swapping adapters or during power transitions. |
Use Scenario: Ruggedized barcode scanner with dual-battery configuration requiring field-replaceable packs and long runtime between charges. IC Role / Device Role / Timing Role: High-efficiency 2A buck charger with programmable current and undervoltage lockout for reliable cold-weather startup down to –40°C. Use Value: Delivers full 2A charge current even at low ambient temperatures, reducing recharge time by >35% versus linear solutions. |
| Avionics Data Recorders | Railway Onboard Communication Units |
|
Use Scenario: Crash-survivable flight data recorder with sealed Li-ion backup battery requiring precision float voltage and ultra-low quiescent drain. IC Role / Device Role / Timing Role: Constant-voltage regulator holding battery at 4.20V/cell ±21mV with 3µA sleep current when main power is lost. Use Value: Extends battery shelf life beyond 5 years while maintaining SOC readiness for emergency recording events. |
Use Scenario: EN50155-compliant train-to-ground radio unit powered from 110VDC rail supply with onboard 24V LiFePO₄ backup battery. IC Role / Device Role / Timing Role: Wide-input (8–28V) charger supporting variable traction power bus voltages and providing adaptive current limiting during regenerative braking surges. Use Value: Prevents adapter overload during transient 110VDC bus dips, ensuring continuous radio operation without brownout-induced packet loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery charger applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3652IMSE#PBF | 42V max input, 2A synchronous buck, integrated MOSFETs, 0.8V ref, no adapter current limiting loop. | Designed for solar/battery hybrid systems; lacks CLP/CLN inputs for adapter current control. | Choose for higher-input-voltage (>28V) or synchronous efficiency-critical designs where adapter current sharing is handled externally. |
| BQ24725ARGER | 3–28V input, 3A, SMBus-controlled, integrated ADC, 0.5% VREF, but requires external FETs and microcontroller interface. | Requires I²C host for configuration; no autonomous analog adapter current limiting. | Choose when centralized BMS control, telemetry, or multi-chemistry algorithm flexibility is required over autonomous analog operation. |
Compared with LT3652IMSE#PBF and BQ24725ARGER, the LT1769IFE#PBF uniquely combines autonomous three-loop analog regulation (CC/CV/adapter current), ultra-low 3µA sleep drain, and TSSOP-20 thermal performance - making it optimal for embedded systems needing zero-firmware, high-reliability battery charging without host dependency.
Availability
LT1769IFE#PBF is available at Aetrix Electronics and suitable for portable medical monitors, industrial handheld terminals, avionics data recorders, railway communication units, and ruggedized field instrumentation requiring stable component supply and long-term production continuity.
Supply support for LT1769IFE#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, industrial, automotive, and communications markets.
The LT1769IFE#PBF belongs to Linear's legacy high-accuracy battery charger IC family, designed specifically for autonomous, firmware-free charging of Li-ion, NiMH, and NiCd batteries in space-constrained, thermally demanding industrial and portable applications.
FAQ
What is the maximum continuous battery charge current supported by the LT1769IFE#PBF?
The LT1769IFE#PBF supports up to 2A continuous DC battery charge current, with internal switch rated for 3A peak. This is achievable in the FE-package TSSOP-20 with adequate PCB copper area for heat sinking, as confirmed by thermal characterization in the LT1769FA datasheet (θJA = 35°C/W). At 2A, junction temperature remains below 125°C under typical ambient conditions.
Does the LT1769IFE#PBF require an external blocking diode between the IC and battery?
No, the LT1769IFE#PBF does not require an external blocking diode. When the AC adapter is removed, the IC enters sleep mode and draws only 3µA from the battery. This is enabled by internal circuitry that isolates the SW node and disables the switch driver, eliminating reverse current paths - a key advantage over older charger architectures.
Can the LT1769IFE#PBF charge batteries with negative-terminal grounding?
Yes, the LT1769IFE#PBF supports ground-referenced battery configurations. Its BAT and SENSE pins accept differential current sensing at either battery terminal, allowing the battery's negative terminal to be tied directly to system ground - simplifying layout and avoiding ground loop complications in systems with shared battery and system grounds.
How is input adapter current limiting implemented in the LT1769IFE#PBF?
The LT1769IFE#PBF implements analog adapter current limiting using dedicated CLP and CLN pins. A sense resistor (RS4) placed between the adapter output and VCC creates a voltage drop; when it exceeds 100mV, the CL1 amplifier reduces charge current in real time. This closed-loop method requires no microcontroller and ensures adapter current stays within safe limits during simultaneous system operation and charging.
What is the purpose of the UVOUT pin on the LT1769IFE#PBF?
The UVOUT pin on the LT1769IFE#PBF is an open-collector status output indicating undervoltage lockout condition. It pulls low when VCC falls below the 6.7V UV threshold and goes high (with external pull-up) when valid input voltage is restored. This signal can be used to trigger system-level alerts or initiate graceful shutdown sequences before power loss occurs.
LT1769IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Battery Chemistry:
- Multi-Chemistry
- Number of Cells:
- -
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- -
- Fault Protection:
- Over Voltage
- Charge Current - Max:
- 2A
- Battery Pack Voltage:
- 20V (Max)
- Voltage - Supply (Max):
- 28V
- Interface:
- -
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT1769IFE#PBF FAQ
1.How can I place an order for LT1769IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1769IFE#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 LT1769IFE#PBF reliable?
The price and inventory of LT1769IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1769IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1769IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1769IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1769IFE#PBF?
LT1769IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1769IFE#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 LT1769IFE#PBF?
For technical support, including LT1769IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1769IFE#PBF requirements.
6.How does Aetrix verify that LT1769IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1769IFE#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 LT1769IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1769IFE#PBF?
All LT1769IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1769IFE#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 LT1769IFE#PBF part is unused and in its original packaging.
Return procedure for LT1769IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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