MAX17303X+T

Key Specs

Spec	Value	Condition	Source
Function	Fuel Gauge		Digi-Key
Battery Chemistry	Lithium Ion/Polymer		Digi-Key
Number Of Cells	1		Digi-Key
Fault Protection	Over Current, Over Temperature, Over Voltage, Short Circuit		Digi-Key
Interface	I2C		Digi-Key
Operating Temperature Range	-40°C ~ 85°C (TA)		Digi-Key
Mounting Type	Surface Mount		Digi-Key
Package Case	15-WFBGA, WLBGA		Digi-Key
Supplier Device Package	15-WLP (1.68x2.45)		Digi-Key

When To Use

• Use the MAX17303X+T in single-cell lithium-ion/polymer battery applications where precise fuel gauging and comprehensive fault protections (overcurrent, overtemperature, overvoltage, and short circuit) are required. Its low quiescent current (24μA typical active, 0.5μA deep ship) makes it ideal for portable devices such as wearables, medical instruments, and IoT sensors needing long battery life.

• Choose this device when I2C interface communication is preferred for system integration, supporting up to 400kHz bus speed, and when SHA-256 authentication is needed for enhanced security in battery management.

• Avoid using the MAX17303X+T in multi-cell battery packs or applications requiring integrated cell balancing, as it supports only a single cell. For multi-cell configurations, consider other Analog Devices fuel gauge ICs with multi-cell support.

• Do not use this device in high-current power delivery systems exceeding 100mA continuous output current or where active power conversion is required; instead, select dedicated power management ICs with higher current ratings.

When Not To Use

1. Output current demand > 100mA continuous: The absolute max output current is 100mA; exceeding this risks damage and inaccurate readings. Use a high-current synchronous buck with external FETs to handle higher load current and maintain efficiency.

2. Application requires galvanic isolation between battery and system: This IC lacks any isolation features and is direct-connected to the battery. Use an isolated flyback converter/controller to provide the necessary galvanic isolation.

3. Power supply noise-sensitive with <1V input-output differential: Since this IC does not regulate output voltage with tight noise specs nor supports low dropout operation, use an LDO regulator for small input-to-output voltage differentials and low noise requirements.

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Application Notes

• The current sense node (connected across the sense resistor) switches rapidly and must have the smallest possible loop area to minimize noise pickup and ensure accurate current measurement.

• The TH pin (temperature measurement pin) is noise-sensitive; route its signal with care, away from high-current or switching nodes, and use proper filtering with the external thermistor.

• Given the very low typical active current of 24μA and deep ship current as low as 0.02μA, heatsinking is generally not required for the MAX17303X+T under normal operating conditions, even at the maximum output current of 100mA.

• For reliable I2C communication at up to 400kHz, ensure proper pull-up resistors (2kΩ to 5kΩ) on SDA and SCL lines, and minimize bus capacitance.

• The device integrates programmable protection thresholds and timers; configure these settings carefully to balance between battery safety and system reliability.

• Use the SHA-256 authentication feature to secure

Gotchas

• Incorrect Sense Resistor Value:
  Mistake: Engineer uses a sense resistor value significantly different from the recommended 10mΩ.
  Failure Mode: This causes inaccurate current measurement, leading to erroneous fuel gauge readings and improper overcurrent protection triggering.
  Fix: Use a precision 10mΩ resistor with 1% tolerance as specified. Confirm resistor value during design and testing.

• Omitting or Using Incompatible Thermistor:
  Mistake: Engineer omits the external NTC thermistor or uses one with unsupported characteristics.
  Failure Mode: Battery temperature compensation and overtemperature protection become unreliable, risking battery damage or premature shutdown.
  Fix: Use a compatible 10kΩ or 100kΩ NTC thermistor matching the device’s supported temperature curves, and connect it properly to the TH pin.

• Insufficient Bypass Capacitor Placement:
  Mistake: Bypass capacitor is omitted or placed too far from the IC supply pins.
  Failure Mode: Power supply noise causes communication errors or unstable operation.
  Fix: Place a 0.1μF ceramic capacitor as close as possible to the IC’s supply pins.