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Analog Devices Inc. LTC3559EUD-1#PBF
- Part No.:
- LTC3559EUD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Battery Chargers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3559EUD-1#PBF.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,175
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Product details
Overview
LTC3559EUD-1#PBF from Analog Devices (formerly Linear Technology) is a linear USB battery charger with dual monolithic synchronous buck regulators, designed for single-cell Li-Ion/Polymer handheld systems. It delivers up to 950mA charge current (programmable via PROG pin), supports temperature-qualified charging via NTC input, and integrates two 400mA buck regulators operating at 2.25MHz - all in a thermally enhanced 16-lead 3mm × 3mm QFN package. It is used in low-power portable devices requiring multiple regulated rails and USB-compliant charging.
For engineers reviewing the LTC3559EUD-1#PBF datasheet, LTC3559EUD-1#PBF pinout, LTC3559EUD-1#PBF application, or LTC3559EUD-1#PBF equivalent, key selection criteria include its 4.100V float voltage (LTC3559-1 variant), HPWR-selectable 20%/100% charge current scaling, Burst Mode®/pulse-skip regulator control, thermal regulation at ~105°C, and integrated bad-battery detection with 0.5-hour timeout.
Technical Context
The LTC3559EUD-1#PBF implements a constant-current/constant-voltage (CC/CV) linear charging algorithm with programmable termination via internal 4-hour safety timer and C/10 detection. Its NTC interface enables cold/hot fault detection using voltage thresholds of 76.5%VCC (cold) and 34.9%VCC (hot), with hysteresis.
Each buck regulator features internal compensation, 2.25MHz fixed-frequency operation, selectable modes via MODE pin (Burst Mode® for <35μA no-load IQ or pulse-skip for low-noise), and ±1% output voltage accuracy over load/temperature. Feedback reference is 800mV with ±20mV tolerance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Float Voltage | 4.100V (LTC3559-1 variant); sets final Li-Ion charge termination point with ±15mV initial accuracy and ±20mV tempco over –40°C to 85°C |
| Max Charge Current | 500mA (HPWR = 5V, RPROG = 1.74kΩ); scalable to 100mA when HPWR = 0V per USB power spec compliance |
| Buck Output Current | 400mA per regulator; supports dual-rail loads like core logic (1.2V) and I/O (2.5V) without external compensation |
| Switching Frequency | 2.25MHz (±14%); enables use of small 4.7μH inductors and reduces EMI in space-constrained portable designs |
| No-Load Quiescent Current | 35μA (Burst Mode®); extends battery runtime during system standby while maintaining fast wake-up response |
| NTC Fault Thresholds | VCOLD = 76.5%VCC, VHOT = 34.9%VCC; provides precise thermal qualification using standard NTC thermistors co-packaged with battery |
| Thermal Regulation Threshold | ~105°C (TLIM); dynamically reduces charge current to prevent die overheating under high ambient or high-power conditions |
Pinout & Package
Package: 16-lead (3mm × 3mm) plastic QFN with exposed thermal pad (Pin 17), rated for –40°C to 85°C operation. Exposed pad must be soldered to PCB ground for electrical integrity and thermal performance (θJA = 68°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Primary analog/digital ground node; connects directly to exposed pad (Pin 17) for low-impedance return path |
| BAT (Pin 2) | Battery charge output | Delivers regulated CC/CV current to single-cell Li-Ion; floats at 4.100V (LTC3559-1); max 950mA sink capability |
| MODE (Pin 3) | Buck regulator mode control | High = Burst Mode® (ultra-low IQ); Low = pulse-skip (low-noise); must not be left floating |
| FB1 / FB2 (Pins 4,10) | Buck feedback inputs | Monitor output voltage via resistor divider; 800mV reference enables 1.2V/2.5V outputs with ±1% regulation |
| EN1 / EN2 (Pins 5,9) | Buck enable inputs | Active-high logic control; allows independent on/off sequencing of each regulator for power domain management |
| HPWR (Pin 12) | Charge current scaling select | High = 100% programmed current (e.g., 500mA); Low = 20% (e.g., 100mA); supports USB 2.0/BC1.2 power profiles |
| NTC (Pin 13) | Temperature sensor input | Accepts voltage divider from VCC–NTC–GND; detects out-of-range battery temp to pause charging safely |
| PROG (Pin 14) | Charge current programming & monitoring | 1.74kΩ to GND sets 500mA; PROG voltage = 1V (HPWR=high) or 0.2V (HPWR=low); IBAT = 800 × IPROG |
| CHRG (Pin 15) | Open-drain status indicator | Low = charging; Hi-Z = complete (C/10); 35kHz modulated blink = NTC fault (1.5Hz) or bad battery (6.1Hz) |
| VCC (Pin 16) | Charger input supply | Accepts 4.3V–5.5V USB or AC adapter input; includes UVLO (4.0V threshold) and differential UVLO (50mV ΔV) |
Key Features
| Feature | Design Value |
|---|---|
| Dual 400mA synchronous bucks | Monolithic design eliminates external compensation; 90%+ efficiency across 2.7V–4.2V input range supports compact dual-rail power delivery |
| USB-compliant charge scaling | HPWR pin toggles between 100% and 20% of programmed current - enabling strict adherence to USB 2.0 (500mA) and BC1.2 (100mA) limits |
| Integrated thermal regulation | Automatic current reduction above ~105°C prevents thermal runaway without external sensors or firmware intervention |
| Intelligent CHRG status signaling | Single open-drain pin conveys four states (charging, done, NTC fault, bad battery) via DC level or unique 35kHz duty-cycle modulation |
| Robust battery protection | Trickle charge (2.9V threshold), automatic recharge (–100mV below float), 4-hour safety timer, and 0.5-hour bad-battery timeout ensure safe Li-Ion handling |
Applications
| Portable Medical Sensors | USB-Powered Handheld Scanners |
|---|---|
Use Scenario: Wearable glucose monitor powered by single-cell Li-Poly with USB recharging and dual-rail MCU + BLE radio operation. IC Role / Device Role / Timing Role: LTC3559EUD-1#PBF acts as primary power manager - charging battery while simultaneously supplying 1.2V (MCU core) and 2.5V (BLE transceiver) from integrated bucks. Use Value: Eliminates need for discrete charger + dual LDOs; Burst Mode® extends idle battery life to >7 days; NTC input ensures safe charging during body-worn operation. |
Use Scenario: Barcode scanner with USB host connection, requiring compliant 500mA charging and clean 3.3V rail (via buck + LDO) for imaging sensor. IC Role / Device Role / Timing Role: LTC3559EUD-1#PBF serves as USB-aware charger and pre-regulator - delivering stable 2.5V to LDO input while managing charge current based on HPWR state. Use Value: HPWR pin enables seamless transition between USB bus-powered (100mA) and self-powered (500mA) modes; pulse-skip mode minimizes noise coupling into image capture circuitry. |
| Low-Power IoT Edge Nodes | SD/Flash-Based MP3 Players |
Use Scenario: Battery-operated environmental sensor node with LoRaWAN radio, recharged via micro-USB port in field deployments. IC Role / Device Role / Timing Role: LTC3559EUD-1#PBF provides autonomous charging supervision and powers ultra-low-power MCU (1.2V) and RF front-end (2.5V) with minimal quiescent draw. Use Value: 35μA no-load IQ in Burst Mode® extends shelf life; thermal regulation prevents overheating in sealed enclosures; CHRG pin enables firmware-based fault logging. |
Use Scenario: Compact MP3 player with flash memory, audio DAC, and OLED display - all powered from single Li-Ion cell with USB recharging. IC Role / Device Role / Timing Role: LTC3559EUD-1#PBF supplies 1.2V to audio codec and 2.5V to display driver while charging battery; CHRG pin drives status LED. Use Value: Integrated trickle charge recovers deeply discharged batteries; automatic recharge maintains full capacity between usage; 4.100V float voltage optimizes Li-Poly cycle life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery charger + dual-buck applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ24195RGER | Switch-mode charger (90% eff.) vs linear (75% eff.); no integrated bucks; requires external regulators | Higher power efficiency but adds BOM cost/complexity; lacks dual-buck integration and NTC interface | Select for high-input-power (>5W) or thermally constrained designs where charger heat dissipation is critical |
| LTC3558EUD#PBF | Same family, single-buck variant; identical charger section and pinout except missing SW2/FB2/EN2 pins | Supports only one regulated rail; suitable when system needs only one post-regulated voltage | Select when second buck is unnecessary - saves board area and simplifies layout while retaining same charging features |
Compared with BQ24195RGER and LTC3558EUD#PBF, the LTC3559EUD-1#PBF uniquely combines USB-programmable linear charging, dual synchronous bucks, and comprehensive battery safety in one QFN - reducing component count and validation effort for dual-rail portable systems.
Availability
LTC3559EUD-1#PBF is available at Aetrix Electronics and suitable for portable medical sensors, USB-powered handheld scanners, and low-power IoT edge nodes requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3559EUD-1#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 ICs, serving industrial, automotive, communications, and healthcare markets.
The LTC3559EUD-1#PBF belongs to Linear's Power Management product line, engineered specifically for space-constrained, battery-powered portable electronics needing integrated charging and multi-rail power conversion without external compensation.
FAQ
What is the float voltage of the LTC3559EUD-1#PBF, and how does it differ from the LTC3559EUD#PBF?
The LTC3559EUD-1#PBF has a nominal float voltage of 4.100V, optimized for Li-Ion cells requiring lower termination voltage to extend cycle life. In contrast, the LTC3559EUD#PBF uses 4.200V. This 100mV difference is factory-trimmed and affects battery longevity and full-charge capacity - users must select the correct variant based on cell chemistry specifications.
How does the HPWR pin affect charge current programming on the LTC3559EUD-1#PBF?
The HPWR pin on the LTC3559EUD-1#PBF selects between two charge current levels: when pulled high (>1.2V), it enables 100% of the current set by the PROG resistor (e.g., 500mA with 1.74kΩ); when pulled low (<0.4V), it scales current to 20% (e.g., 100mA). This allows dynamic compliance with USB 2.0 (500mA) and USB Battery Charging 1.2 (100mA) specifications using a single LTC3559EUD-1#PBF design.
Can the LTC3559EUD-1#PBF operate without an NTC thermistor, and what happens if NTC is grounded?
Yes - grounding the NTC pin disables temperature qualification on the LTC3559EUD-1#PBF, allowing charging regardless of battery temperature. However, this removes critical safety protection. If NTC is left floating, the internal weak pull-down ensures safe default behavior (no charging). The LTC3559EUD-1#PBF will not initiate charging unless NTC voltage falls within valid cold/hot thresholds - a deliberate fail-safe design.
What is the purpose of the CHRG pin on the LTC3559EUD-1#PBF, and how do its four states manifest electrically?
The CHRG pin on the LTC3559EUD-1#PBF is an open-drain status indicator with four distinct states: low (charging), high-impedance (charge complete, IBAT < C/10), 35kHz modulated with 1.5Hz duty-cycle sweep (NTC fault), or 35kHz modulated with 6.1Hz sweep (bad battery). This enables both human-readable LED blinking and firmware-decodable fault signatures - all using a single pin on the LTC3559EUD-1#PBF.
Does the LTC3559EUD-1#PBF require external compensation components for its buck regulators?
No - the LTC3559EUD-1#PBF integrates fully compensated synchronous buck regulators. Its internal compensation eliminates the need for external type-II or type-III networks, reducing BOM count and layout complexity. Users only need to connect standard output capacitors (e.g., 10μF ceramic) and inductors (e.g., 4.7μH) - verified in the LTC3559EUD-1#PBF typical application circuit.
LTC3559EUD-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Battery Chemistry:
- Lithium Ion/Polymer
- Number of Cells:
- 1
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- -
- Fault Protection:
- -
- Charge Current - Max:
- 950mA
- Battery Pack Voltage:
- 4.2V
- Voltage - Supply (Max):
- 5.5V
- Interface:
- USB
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LTC3559EUD-1#PBF FAQ
1.How can I place an order for LTC3559EUD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3559EUD-1#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 LTC3559EUD-1#PBF reliable?
The price and inventory of LTC3559EUD-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3559EUD-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3559EUD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3559EUD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3559EUD-1#PBF?
LTC3559EUD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3559EUD-1#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 LTC3559EUD-1#PBF?
For technical support, including LTC3559EUD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3559EUD-1#PBF requirements.
6.How does Aetrix verify that LTC3559EUD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3559EUD-1#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 LTC3559EUD-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3559EUD-1#PBF?
All LTC3559EUD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3559EUD-1#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 LTC3559EUD-1#PBF part is unused and in its original packaging.
Return procedure for LTC3559EUD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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