Part: LTC4162-S — Analog Devices (Linear Technology)

Type: Synchronous Step-Down Switching Battery Charger and PowerPath Manager

Description: A 4.5–35 V input, 3.2 A synchronous step-down switching battery charger and PowerPath manager for lead-acid batteries, featuring a 16-bit digital telemetry system and I2C interface.

Operating Conditions:

• Supply voltage: 4.5–35 V
• Operating junction temperature: -40 to 125 °C
• Battery voltage: 2.7–35 V
• DVCC logic reference level: 1.8–5.5 V

Absolute Maximum Ratings:

• Max supply voltage (VIN, BATSENS+, VOUT, VOUTA): 36 V
• Max switch current (ISW): ±3.5 A
• Max storage temperature: -65 to 150 °C

Key Specs:

• Input Supply Voltage (VIN): 4.5–35 V
• Max Charge Current: 3.2 A (from description)
• Switching Frequency (fOSC): 1.4–1.6 MHz (typ 1.5 MHz)
• Primary Switch On-Resistance (RSWITCH): 90 mΩ (typ)
• Rectifier Switch On-Resistance (RRECT): 90 mΩ (typ)
• VIN Charger Enable Undervoltage Lockout (VIN_UVLO) Rising Threshold: 4.4 V (typ)
• I2C Address: 0b1101000[R/W]
• SCL Clock Frequency (FSCL): 400 kHz (max)

Features:

• Lead-Acid Battery Charger with Absorb and Equalize
• Wide Charging Input Voltage Range: 4.5V to 35V
• High Efficiency Synchronous Operation
• 16-Bit Digital Telemetry System Monitors V BAT , I BAT , R BAT , T BAT , T DIE , V IN , I IN , V OUT
• Charges 6V, 12V, 18V and 24V Lead-Acid Batteries
• Input MPPT for Solar Panel Inputs
• Low Loss PowerPath™
• Instant-On Operation with Discharged or Missing Battery
• Temperature Controlled Charging

Applications:

• Medical Instruments
• USB-C Power Delivery
• Industrial Handhelds
• Ruggedized Notebook
• Tablet Computers

Package:

• 28-pin 4mm × 5mm × 0.75mm QFN surface mount package

• n Lead-Acid Battery Charger with Absorb and Equalize
• n Wide Charging Input Voltage Range: 4.5V to 35V
• n High Efficiency Synchronous Operation
• n 16-Bit Digital Telemetry System Monitors V BAT , I BAT , R BAT , T BAT , T DIE , V IN , I IN , V OUT
• n Charges 6V, 12V, 18V and 24V Lead-Acid Batteries
• n Input Undervoltage Charge Current Limit Loop
• n Input MPPT for Solar Panel Inputs
• n Input Current Limit Prioritizes System Load Output
• n Low Loss PowerPath™
• n Instant-On Operation with Discharged or Missing Battery
• n Temperature Controlled Charging
• n Pin Compatible with Li-Ion and LiFePO 4 Versions

• n Medical Instruments
• n USB-C Power Delivery
• n Industrial Handhelds
• n Ruggedized Notebook
• n Tablet Computers

LTC4162 Pinout – QFN-28 (4mm × 5mm)

Notes

• Exposed Pad (Pin 29): The exposed pad on the bottom of the QFN package is connected to AGND and must be soldered to the PCB for proper thermal and electrical performance.
• Power Pins: INTVCC (Pin 2), DVCC (Pin 15), VIN (Pin 7), and VCC2P5 (Pin 8) require appropriate decoupling capacitors.
• Ground Pins: PGND (Pins 23, 24) and AGND (Pin 29) should be connected to a solid ground plane.
• SMBus Interface: Pins 13 (SDA) and 14 (SCL) implement the SMBus communication protocol with open-drain outputs requiring pull-up resistors.
• Dual Outputs: VOUT (Pins 27, 28) and SW (Pins 25, 26) are duplicated for layout flexibility.

The l denotes the specifications which apply over the full specified operating junction temperature range, otherwise specifications are at T A = 25°C (Note 4). V IN = 18V, DVCC = 3.3V, R SNSI = 10mΩ, RSNSB = 10mΩ unless otherwise noted.

Rev B

When the switching battery charger is enabled at an elevated ambient temperature, LTC4162 self heating may push its junction temperature to an unacceptable level. To prevent overheating the LTC4162 monitors its own die_temp and automatically reduces the icharge_dac to limit power dissipation. The differential servo voltage at CSP to CSN can drop to as low as 1mV giving about 3% (1/32) of the maximum charge current. The thermal regulation algorithm achieves this by enforcing a maximum icharge_dac setting which drops linearly from 31 to 0 as die_temp increases from thermal_reg_start_temp (default 120°C) to thermal_reg_end_temp (default 125°C). When the thermal regulation algorithm is active, charge_status becomes thermal_reg_active. A thermal_reg_active_alert can be set with en_thermal_reg_active_alert and cleared by writing either back to 0. Thermal regulation can be programmed to any temperature within the LTC4162's operating range.

9V to 35V, 3.2A Step-Down Switching Battery Charger with PowerPath