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Dual-Input Linear Chargers, Smart Power Selector with Advanced Battery Temperature Monitoring

Safely Charges a Li+ Cell Following JEITA-Recommended Safe Charging Methods

Product Details

The MAX8934_ dual-input Li+/Li-Poly linear battery chargers with Smart Power Selector™ safely charge a single Li+/Li-Poly cell in accordance with JEITA recommendations. The MAX8934_ monitors the battery temperature (TBATT) while charging, and automatically adjusts the fast-charge current and charge termination voltage as the battery temperature varies. The MAX8934_ also monitors the battery temperature while the battery is discharging, and provides a warning flag (active-low OT) to the system in the event that the battery is over temperature. Two safety profiles are supported (see Figure 6 in the full data sheet for details). An ultra-low IQ, always-on LDO provides an additional 3.3V supply for system power.

The MAX8934_ operates with either separate inputs for USB and AC adapter power*, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included on-chip. No external MOSFETs are required.

The MAX8934_ features a Smart Power Selector to make the best use of limited USB or adapter power. Input current limit and battery charge current limit are independently set. Input power not used by the system charges the battery. Charge current limit and DC current limit can be set up to 1.5A and 2A, respectively, while USB input current can be set to 100mA or 500mA for the MAX8934A/MAX8934B/MAX8934C/MAX8934E and up to 1.5A (max) for the MAX8934D. Automatic input selection switches the system load from battery to external power.

The MAX8934A provides a SYS output voltage of 5.3V, while the MAX8934B–MAX8934E provide a SYS output voltage of 4.35V.

Other features include overvoltage protection (OVP), open-drain charge status and fault outputs, power-OK monitors, charge timers, and a battery thermistor monitor. Additionally, on-chip thermal limiting reduces the battery charge-rate to prevent charger overheating. The MAX8934_ is available in a 28-pin, 4mm x 4mm, TQFN package.

Key Features

  • Li+ Charger with Smart Power Selector, No External MOSFETs Needed
  • Monitors Battery Temperature and Adjusts Charge Current and Termination Voltage Automatically per JEITA Recommendations
  • Active-Low OT Flags System of a Hot Battery During Discharge
  • Ultra-Low IQ, Always-On 3.3V LDO
  • Common or Separate USB and Adapter Inputs
  • Automatic Adapter/USB/Battery Switchover
  • Load Peaks in Excess of Adapter Rating are Supported by Battery
  • Input OVP to 16V (DC) and 9V (USB)
  • 40mΩ SYS-to-BATT Switch
  • Thermal Regulation Prevents Overheating
  • 4.35V or 5.3V SYS Regulation Voltage
  • 1.5A (max) USB Input Current Limit (MAX8934D)

Applications/Uses

  • Digital Still Cameras and Digital Video Cameras
  • Handheld Game Systems
  • PDAs, Palmtop, and Wireless Handhelds
  • Portable Media, MP3 Players, and PNDs
Parametric specs for Battery Chargers
Charging VIN (V) (max) 6.6
Max. ICHG (A) 1.5
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 14
Charger (V) 4.2
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/28
Budgetary
Price (See Notes)
$2.29 @1k
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Simplified Block Diagram

MAX8934A, MAX8934B, MAX8934C, MAX8934D, MAX8934E: Typical Operating Circuit MAX8934A, MAX8934B, MAX8934C, MAX8934D, MAX8934E: Typical Operating Circuit Zoom icon

Technical Docs

Design & Development

Click any title below to view the detail page where available.

Description

The MAX8934A evaluation kit (EV kit) is a fully assembled and tested circuit for evaluating the MAX8934A dual-input linear charger and Smart Power Selector with advanced temperature monitoring.

The EV kit charges a single-cell lithium-ion (Li+) battery from either a DC input (AC adapter) or a USB 100mA/500mA source, and provides system power from the DC input, USB input, or battery. The DC input has a resistor-adjustable current limit up to 2A, while the USB input-current limit is logic programmable to 100mA/500mA. USB suspend mode is also supported. The charge current limit is adjustable from 300mA to 1.5A. The system load has priority over the charger, so charge current is reduced as necessary to prevent input overload. Charge current is also thermally regulated. Advanced battery temperature monitoring adjusts charge current and termination voltage automatically.

The EV kit comes standard with the MAX8934A installed, but can also be used to evaluate the MAX8934B, MAX8934C, MAX8934D, and MAX8934E by replacing the MAX8934A (U1) with the MAX8934_. Request a free sample of the MAX8934_ when ordering the EV kit.

View Details

Features

  • Battery Temperature Monitor Adjusts Charge Current and Termination Voltage Automatically
    • Potentiometer Adjustment Available
    • 0603 Thermistor Footprint Available
    • Advanced Thermistor Configuration Available (R21, R22)
    • Thermistor Enable Input (THMEN)
  • Adjustable Input-Current Limit and Fast-Charge Current Limit
    • Fast-Charge Current Limit: 750mA and 1.5A (JU5)
    • USB Input-Current Limit: 475mA and 95mA (PEN1, PEN2)
    • DC Input-Current Limit Up to 2A (R2)
  • Status LED Indicators: Active-Low DOK, Active-Low UOK, Active-Low CHG, Active-Low DONE, Active-Low FLT, and Active-Low OT
  • USB Suspend Logic Input
  • 3.3V Always-On LDO
  • Fully Assembled and Tested

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Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 6.6
Max. ICHG (A) 1.5
Cell Chemistry Li-Ion
Li-Polymer
# Lithium Ion Cells 1
Protected VIN (V) (max) 14
Charger (V) 4.2
Oper. Temp. (°C) -40 to +85
Package/Pins TQFN/28
Budgetary
Price (See Notes)
$2.29 @1k

Key Features

  • Li+ Charger with Smart Power Selector, No External MOSFETs Needed
  • Monitors Battery Temperature and Adjusts Charge Current and Termination Voltage Automatically per JEITA Recommendations
  • Active-Low OT Flags System of a Hot Battery During Discharge
  • Ultra-Low IQ, Always-On 3.3V LDO
  • Common or Separate USB and Adapter Inputs
  • Automatic Adapter/USB/Battery Switchover
  • Load Peaks in Excess of Adapter Rating are Supported by Battery
  • Input OVP to 16V (DC) and 9V (USB)
  • 40mΩ SYS-to-BATT Switch
  • Thermal Regulation Prevents Overheating
  • 4.35V or 5.3V SYS Regulation Voltage
  • 1.5A (max) USB Input Current Limit (MAX8934D)

Applications/Uses

  • Digital Still Cameras and Digital Video Cameras
  • Handheld Game Systems
  • PDAs, Palmtop, and Wireless Handhelds
  • Portable Media, MP3 Players, and PNDs

Description

The MAX8934_ dual-input Li+/Li-Poly linear battery chargers with Smart Power Selector™ safely charge a single Li+/Li-Poly cell in accordance with JEITA recommendations. The MAX8934_ monitors the battery temperature (TBATT) while charging, and automatically adjusts the fast-charge current and charge termination voltage as the battery temperature varies. The MAX8934_ also monitors the battery temperature while the battery is discharging, and provides a warning flag (active-low OT) to the system in the event that the battery is over temperature. Two safety profiles are supported (see Figure 6 in the full data sheet for details). An ultra-low IQ, always-on LDO provides an additional 3.3V supply for system power.

The MAX8934_ operates with either separate inputs for USB and AC adapter power*, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included on-chip. No external MOSFETs are required.

The MAX8934_ features a Smart Power Selector to make the best use of limited USB or adapter power. Input current limit and battery charge current limit are independently set. Input power not used by the system charges the battery. Charge current limit and DC current limit can be set up to 1.5A and 2A, respectively, while USB input current can be set to 100mA or 500mA for the MAX8934A/MAX8934B/MAX8934C/MAX8934E and up to 1.5A (max) for the MAX8934D. Automatic input selection switches the system load from battery to external power.

The MAX8934A provides a SYS output voltage of 5.3V, while the MAX8934B–MAX8934E provide a SYS output voltage of 4.35V.

Other features include overvoltage protection (OVP), open-drain charge status and fault outputs, power-OK monitors, charge timers, and a battery thermistor monitor. Additionally, on-chip thermal limiting reduces the battery charge-rate to prevent charger overheating. The MAX8934_ is available in a 28-pin, 4mm x 4mm, TQFN package.

Simplified Block Diagram

MAX8934A, MAX8934B, MAX8934C, MAX8934D, MAX8934E: Typical Operating Circuit MAX8934A, MAX8934B, MAX8934C, MAX8934D, MAX8934E: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal.