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LINEAR TECHNOLOGY - LTC3559 Data Sheet User Guide Manual

Summary

The LTC3559 is a high-performance USB battery charger featuring dual, highly efficient synchronous buck regulators and sophisticated charge management for single-cell Li-Ion/Polymer batteries. This technical manual provides comprehensive details on its operation, including programmable charging up to 950mA, NTC temperature monitoring, and power-saving modes. It is the ideal solution for embedded systems developers designing low-power handheld electronics and portable devices requiring precise management of multiple regulated supply rails.

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LTC3559/LTC3559-1

Linear USB Battery Charger with Dual Buck Regulators

FEATURES DESCRIPTION Battery Charger

The LTC®3559/LTC3559-1 are USB battery chargers with

n Standalone USB Charger

dual high effi ciency buck regulators. The parts are ideally

n Up to 950m A Charge Current Programmable via

suited to power single-cell Li-Ion/Polymer based handheld

Single Resistor applications needing multiple supply rails. n HPWR Input Selects 20% or 100% of Programmed

Battery charge current is programmed via the PROG pin

Charge Current

and the HPWR pin, with capability up to 950m A at the BAT

n NTC Input for Temperature Qualifi ed Charging

pin. The battery charger has an NTC input for temperature

n Internal Timer Termination

qualifi ed charging. The CHRG pin allows battery status to

n Bad Battery Detection

be monitored continuously during the charging process.

n CHRG Indicates C/10 or Timeout

An internal timer controls charger termination.

Buck Regulators

Each monolithic synchronous buck regulator provides up

n 400m A Output Current

to 400m A of output current while operating at effi ciencies

n 2.25MHz Constant Frequency Operation

greater than 90% over the entire Li-Ion/Polymer range.

n Zero Current in Shutdown

A MODE pin provides the fl exibility to place both buck

n Low Noise Pulse Skip Operation or Power Saving

regulators in a power saving Burst Mode® operation or a

Burst Mode Operation

low noise pulse skip mode.

n Low No-Load Quiescent Current: 35μA

n Available in a Low Profi le Thermally Enhanced The LTC3559/LTC3559-1 are offered in a low profi le ther-

16-Lead 3mm × 3mm QFN Package mally enhanced 16-lead (3mm × 3mm) QFN package. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. APPLICATIONS All other trademarks are the property of their respective owners.

n SD/Flash-Based MP3 Players

n Low Power Handheld Applications

TYPICAL APPLICATION USB Charger Plus Dual Buck Regulators

UP TO 500m A

VCC BATUSB (4.3V TO 5.5V) SINGLE

OR AC ADAPTOR

1μF Li-lon CELL

(2.7V TO 4.2V)

NTC 2.2μF

LTC3559

PROG SW1

CHRG FB1

DIGITAL

HPWR 4.7μH

CONTROL 1.2V

EN2 FB2

MODE 649k

EXPOSED

GND PAD

3559 TA01

3559fb

Page Summary Contents For LINEAR TECHNOLOGY - LTC3559 Data Sheet User Guide Manual

Page 1 LTC3559/LTC3559-1 Linear USB Battery Charger with Dual Buck Regulators FEATURES DESCRIPTION Battery Charger The LTC®3559/LTC3559-1 are USB battery chargers with n Standalone USB Charger dual high effi...
Page 2 LTC3559/LTC3559-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VCC (Transient); TOP VIEW t < 1ms and Duty Cycle < 1% ....................... –0.3V to 7V VCC (Static) ........................
Page 3 LTC3559/LTC3559-1 ELECTRICAL CHARACTERISTICS The l denotes specifi cations that apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. SYMBOL PARAMETER CONDITIONS...
Page 4 LTC3559/LTC3559-1 ELECTRICAL CHARACTERISTICS The l denotes specifi cations that apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. SYMBOL PARAMETER CONDITIONS...
Page 5 LTC3559/LTC3559-1 TYPICAL PERFORMANCE CHARACTERISTICS Battery Charge Current Battery Charge Current Battery Charge Current vs Ambient Temperature in vs Supply Voltage vs Battery Voltage (LTC3559) Ther...
Page 6 LTC3559/LTC3559-1 TYPICAL PERFORMANCE CHARACTERISTICS CHRG Pin Output Low Voltage vs Temperature CHRG Pin I-V Curve Timer Accuracy vs Supply Voltage VCC = 5V VCC = 5V ICHRG = 5m A BAT = 3.8V TEMPERATU...
Page 7 FF IC IE FF IC IE LTC3559/LTC3559-1 TYPICAL PERFORMANCE CHARACTERISTICS Buck Regulator Enable Buck Regulator PMOS RDS(0N) Buck Regulator NMOS RDS(0N) Thresholds vs Temperature vs Temperature (LTC3559)...
Page 8 LTC3559/LTC3559-1 TYPICAL PERFORMANCE CHARACTERISTICS Buck Regulator Pulse Skip Mode Buck Regulator Start-Up Transient Operation VOUT VOUT 500m V/DIV 20m V/DIV (AC) INDUCTOR SW CURRENT 2V/DIV IL 200m ...
Page 9 LTC3559/LTC3559-1 PIN FUNCTIONS GND (Pin 1): Ground, Connect to Exposed Pad (Pin 17). can toggle between low power and high power modes per USB specifi cation. A weak pull-down current is internally B...
Page 10 LTC3559/LTC3559-1 BLOCK DIAGRAM VIN BAT 1x 800x BODY MAXER HPWR CA TA LOGIC NTC REF BATTERY CHARGER UNDERVOLTAGE EN2 LOCKOUT MODEEN FB1 VFB CONTROL SW1 VC LOGIC OT Gm TEMPERATURE TDIE 0.8V BUCK REGULA...
Page 11 LTC3559/LTC3559-1 OPERATION The LTC3559/LTC3559-1 are linear battery chargers with at the BAT pin via a single PROG resistor. The actual BAT dual monolithic synchronous buck regulators. The buck pin c...
Page 12 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Suspend Mode mode, the 4-hour timer is started. After the safety timer expires, charging of the battery will discontinue and no The battery charger can also ...
Page 13 LTC3559/LTC3559-1 APPLICATIONS INFORMATION In any mode, the actual battery current can be determined charge current has dropped to below 10% of the full-scale by monitoring the PROG pin voltage and us...
Page 14 LTC3559/LTC3559-1 APPLICATIONS INFORMATION NTC Thermistor value of R25 or approximately 54k (for a Vishay “Curve 1” thermistor, this corresponds to approximately 40°C). If The battery temperature is m...
Page 15 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Alternate NTC Thermistors and Biasing In the explanation below, the following notation is used. The battery charger provides temperature qualifi ed R25 = Val...
Page 16 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Solving these equations for RNTC|COLD and RNTC|HOT For example, to set the trip points to 0°C and 45°C with results in the following: a Vishay Curve 1 thermi...
Page 17 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Power Dissipation Furthermore, the voltage at the PROG pin will change proportionally with the charge current as discussed in The conditions that cause the L...
Page 18 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Average, rather than instantaneous, battery current may be the current from building up in the cable too fast thus of interest to the user. For example, if a...
Page 19 LTC3559/LTC3559-1 APPLICATIONS INFORMATION most applications. Experimentation with capacitor sizes regulators will automatically skip pulses as needed to between 2p F and 22p F may yield improved tran...
Page 20 LTC3559/LTC3559-1 APPLICATIONS INFORMATION leakage pulled to ground through a 10k resistor on the Buck Switching Regulator Inductor Selection switch (SW1 or SW2) pin when in shutdown. The buck regulat...
Page 21 LTC3559/LTC3559-1 APPLICATIONS INFORMATION Table 2 Recommended Inductors INDUCTOR TYPE L (μH) MAX IDC(A) MAX DCR(Ω) SIZE IN MM (L × W × H) MANUFACTURER DB318C 4.7 1.07 0.1 3.8 × 3.8 × 1.8 Toko 3.3 1.2...
Page 22 LTC3559/LTC3559-1 FF IC IE TYPICAL APPLICATIONS The Output Voltage of a Buck Regulator Is Programmed for 3.3V. When BAT Voltage Approaches 3.3V, the Regulator Operates in Dropout and the Output Voltag...
Page 23 LTC3559/LTC3559-1 TYPICAL APPLICATIONS The Battery Can be Charged with Up to 950m A of Charge Current. Buck Regulator 2 Is Enabled Only After VOUT1 Is Up to Approximately 0.7V. This Provides a Sequenc...
Page 24 LTC3559/LTC3559-1 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC3550 Dual Input USB/AC Adapter Li-Ion Battery Charger with Synchronous Buck Converter, Effi ciency: 93%, Adjustable Output at Adjust...

Manual Details

Brand Linear
Pages 24
File Size 315.58 KB
Published June 05, 2026
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Frequently Asked Questions

What is the programmable charge current for the battery charger?

The battery charge current is programmable via the PROG pin and the HPWR pin, with a capability up to 950mA at the BAT pin.

Does the device offer temperature-qualified charging?

Yes, it has an NTC input for temperature qualified charging through the CHRG pin.

How do I manage power consumption or reduce noise in operation?

Use the MODE pin to place both buck regulators into a low noise pulse skip mode (Burst Mode Operation) or Power Saving Burst Mode operation.

What are the operating temperature ranges for this component?

The product has an Operating Temperature Range of –40°C to 85°C, and a Storage Temperature range of –65°C to 125°C.