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LINEAR TECHNOLOGY - LTC4101 Data Sheet

Summary

This single-chip smart controller provides an advanced, highly efficient solution for managing battery charging up to 4A. Designed for builders of portable instruments, data storage systems, and backup servers, it simplifies complex power management through comprehensive SMBus compliance and continuous SafetySignal monitoring. The manual details its comprehensive electrical specifications, programmability features (voltage/current limits), and operational guidelines, ensuring optimal performance and system reliability in demanding embedded applications.

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LTC4101 Smart Battery

Charger Controller FEATURES DESCRIPTIO

Single Chip Smart Battery Charger Controller The LTC®4101 Smart Battery Charger is a single chip

100% Compliant (Rev. 1.1) SMBus Support Allows charging solution that dramatically simplifies construc- for Operation with or without Host tion of an SBS compliant system. The LTC4101 imple-

Up to 4A Charging Current Capability ments a Level 2 charger function whereby the charger can

High Efficiency Synchronous Buck Charger be programmed by the battery or by the host. A Safety Signal VBAT Optimized 3V to 5.5V on the battery being charged is monitored for tempera- SMBus Accelerator Improves SMBus Timing ture, connectivity and battery type information. The SMBus Hardware Interrupt and SMBAlert Response interface remains alive when the AC power adapter is Eliminate Interrupt Polling removed and responds to all SMBus activity directed to 0.5V Dropout Voltage; Maximum Duty Cycle > 98% it, including Safety Signal status (via the Charger Status AC Adapter Current Limit Maximizes Charge Rate command). The charger also provides an interrupt to the ±0.8% Voltage Accuracy; ±4% Current Accuracy host whenever a status change is detected (e.g., battery 10-Bit DAC for Charge Current Programming removal, AC adapter connection).

11-Bit DAC for Charger Voltage Programming

Charging current and voltage are restricted to chemistry-

User-Selectable Overvoltage and Overcurrent Limits

specific limits for improved system safety and reliability.

High Noise Immunity Safety Signal Sensor

Limits are programmable by two external resistors. Addi-

Available in a 24-Pin SSOP Package

tionally, the maximum average current from the AC adapter APPLICATIO is programmable to avoid overloading the adapter when simultaneously supplying load current and charging

Portable Instruments and Computers

current. When supplying system load current, charging

Data Storage Systems and Battery Backup Servers

current is automatically reduced to prevent adapter

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All

overload.

other trademarks are the property of their respective owners. Protected by U.S. Patents including 6650174, 5723970.

TYPICAL APPLICATIO DCIN 9V to 12V, 2A 0.1µF

6.04k VBAT PART

3V 1.21k < 5.5V LTC4101

TO 5.5V

> 5.5V LTC4100

LTC4101 0.1µF 0.05Ω

VDD DCIN

DCDIV INFET 5k

CHGEN CHGEN CLP SYSTEM LOAD

ACP ACP CLN 5µF SMART BATTERY

SMBALERT TGATE

SCL BGATE

SDA PGND 5µF

THB CSP THA BAT ILIM VSET

VLIM ITH 0.03µF IDC GND 6.04k10k

SMBALERT# Safety Signal

SMBCLK SMBCLK SMBDAT SMBDAT 4101 F01a

Figure 1. 1A Smart Battery Charger

Page Summary Contents For LINEAR TECHNOLOGY - LTC4101 Data Sheet

Page 1 LTC4101 Smart Battery Charger Controller FEATURES DESCRIPTIO Single Chip Smart Battery Charger Controller The LTC®4101 Smart Battery Charger is a single chip 100% Compliant (Rev. 1.1) SMBus Support Al...
Page 2 LTC4101 ABSOLUTE AXI RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW Voltage from VDD to GND 7V/–0.3V TGATE CLP Voltage from CHGEN, DCDIV, SDA, SCL PGND CLN and SMBALERT to GND 7V/–0.3V BGATE BAT V...
Page 3 LTC4101 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 20V, VDD = 3.3V, VBAT = 4V...
Page 4 LTC4101 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 20V, VDD = 3.3V, VBAT = 4V...
Page 5 LTC4101 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VDCIN = 20V, VDD = 3.3V, VBAT = 4V...
Page 6 LTC4101 TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. INFET Response Time to Reverse Current Output Voltage vs Output Current PWM Frequency vs Duty Cycle Vgs OF PFET (2V/DIV) V...
Page 7 LTC4101 TYPICAL PERFOR A CE CHARACTERISTICS OU TP UT UR RE NT RR OR (m A) TA = 25°C unless otherwise noted. Charging Current Error Transfer Function of Charger VDD = 5V VDD = 5V IBAT = 0.120A VDCIN = ...
Page 8 LTC4101 PI FU CTIO S THB (Pin 15): Safety Signal Force/Sense Pin to Smart ITH (Pin 19): Control Signal of the Inner Loop of the Battery. See description of operation for more detail. The Current Mode ...
Page 9 LTC4101 BLOCK DIAGRA C4 VBAT 100Ω 3k BAT 11-BIT RSENSE VDAC GND 20µF CA1 3k CSP OSCILLATOR CSP WATCHDOG BUFFERED SYSTEM DETECT t ON gm = 1m LOAD 20µF EA CLP +– TGATE ICMP CSP Q2 PWM IREV LOGIC D1 BGAT...
Page 10 LTC4101 TEST CIRCUIT LTC4101 EA BAT VDAC VDAC FOR VDAC VDAC CSP BAT ITH DCIN BATVSET CLN CLP LT1055 4101 TC01 OPERATIO Overview (Refer to Block Diagram) block; if the commands exceed the programmed li...
Page 11 LTC4101 OPERATIO to set the bottom MOSFET on time. The result is quasi- Charger Start-Up constant frequency operation: the converter frequency When the charger is enabled, it will not begin switching ...
Page 12 LTC4101 OPERATIO Input, Output or Input/Output: A description of the data Charger Status() ('h13) supplied to or returned by the function. Description: The SMBus Host uses this command to read Charger...
Page 13 LTC4101 OPERATIO Table 1: Summary of Supported Charger Functions SMBus Command Data Function Access Address Code Type D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 DO Charger Spec Info() 7'b0001_...
Page 14 LTC4101 OPERATIO The RES_UR bit is set only when the Safety Signal resis- Charging Current() ('h14) tance value is less than 575Ω. Description: The Battery, System Host or other master de- ALARM_INHIB...
Page 15 LTC4101 OPERATIO table defines the maximum permissible value of disabling the LOWI current mode of the IDAC. CHARGING_VOLTAGE that will not set the VOLTAGE_OR • SMBus Protocol: Write Word. in the Char...
Page 16 LTC4101 OPERATIO SMBus Accelerator Pull-Ups Wake-up Charging Mode Both SCL and SDA have SMBus accelerator circuits which The following conditions must be met in order to allow reduce the rise time on ...
Page 17 LTC4101 OPERATIO Controlled Charging Algorithm Overview 7. RESET_TO_ZERO is set in the Charger Mode() function. The following conditions must be met in order to allow 8. CHGEN pin is pulled low by an ...
Page 18 LTC4101 OPERATIO When AC is present, the LTC4101 samples the value of the The Safety Signal impedance is interpreted according to Safety Signal and updates the Charger Status register ap- Table 4. pro...
Page 19 LTC4101 OPERATIO The ILIM Decoder Block The VLIM Decoder Block The value of an external resistor connected from this pin The value of an external resistor connected from this pin to GND determines one...
Page 20 LTC4101 CH AR GE AT (V OPERATIO The Voltage DAC Block IPROG (FROM CA1 AMP) Note that the charger output voltage is offset by VREF. IDC Therefore, the value of VREF is subtracted from the SMBus Chargin...
Page 21 LTC4101 OPERATIO the input FET is turned off slowly. If the voltage between This feature is created by sensing total adapter output DCIN and CLP is ever less than –25m V, then the input FET current an...
Page 22 LTC4101 APPLICATIO S I FOR ATIO Charge Termination Issues Warning Batteries with constant current charging and voltage- DO NOT CHANGE THE VALUE OF RILIM DURING OPERA- based charger termination might e...
Page 23 LTC4101 APPLICATIO S I FOR ATIO Accepting larger values of ∆IL allows the use of low transfer capacitance CRSS, input voltage and maximum inductances, but results in higher output voltage ripple outpu...
Page 24 LTC4101 APPLICATIO S I FOR ATIO Using excessively large MOSFETs relative to the IMAX Soft-Start and Undervoltage Lockout charge current they are working with will actually reduce The LTC4101 is soft-s...
Page 25 LTC4101 APPLICATIO S I FOR ATIO Input and Output Capacitors The output capacitor (C3) is also assumed to absorb output switching current ripple. The general formula for In the 4A Lithium Battery Charg...
Page 26 LTC4101 APPLICATIO S I FOR ATIO PCB Layout Considerations 4. Place the output current sense resistor right next to the inductor output but oriented such that the IC’s For maximum efficiency, the switc...
Page 27 LTC4101 PACKAGE DESCRIPTIO G Package 24-Lead Plastic SSOP (5.3mm) (Reference LTC DWG # 05-08-1640) 0.42 ±0.03 0.65 BSC RECOMMENDED SOLDER PAD LAYOUT BSC 0.05 NOTE: (.002) 1. CONTROLLING DIMENSION: MIL...
Page 28 LTC4101 TYPICAL APPLICATIO LTC4101 Li-Ion Battery Charger ILIM = 4A/VLIM = 4.240V, Adapter Rating = 2.7A RCL 0.033Ω 9V TO 12V SYSTEM C9 LOAD FROM WALL C1 R1 ADAPTER 0.1µF 4.9k INFET CLNCLP DCIN TGATE ...

Manual Details

Brand Linear
Pages 28
File Size 291.74 KB
Published July 15, 2026
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Frequently Asked Questions

What protection features does the LTC4101 offer?

It provides user-selectable overvoltage/overcurrent limits, a SafetySignal sensor, and automatically reduces current when simultaneously supplying load power.

How reliable is its communication with a host system?

The device supports 100% compliant SMBus, utilizing an Accelerator function and maintaining status awareness via hardware interrupts even if the AC adapter disconnects.

Can I precisely set the output charging parameters?

Yes, it features a 10-Bit DAC for precise charge current programming and an 11-Bit DAC for charger voltage programming.