MAX17303X+T vs BQ27Z746YAHR: Battery Fuel Gauge IC Comparison
1. Quick verdict
For single-cell Li-Ion/Polymer battery fuel gauging with integrated protection and minimal power consumption, the MAX17303X+T offers a more comprehensive protection suite with programmable thresholds and very low deep-sleep current, making it ideal for ultra-low-power, long-life portable devices. The BQ27Z746YAHR is better suited when higher output current capability (up to 1 A) and a wider operating input voltage range (down to 2.0 V) are required, such as in applications demanding higher load currents or more flexible power supply conditions.
2. Spec comparison table
| Spec | MAX17303X+T | BQ27Z746YAHR | Notes |
|---|---|---|---|
| Function | Fuel Gauge | Fuel Gauge | Equivalent function. |
| Battery Chemistry | Lithium Ion/Polymer | Lithium Ion/Polymer | Equivalent. |
| Number of Cells | 1 | 1 | Equivalent. |
| Fault Protection | Over Current, Over Temperature, Over Voltage, Short Circuit | Over Current, Over Temperature, Over/Under Voltage, Short Circuit | Both offer comprehensive protection; BQ27Z746YAHR adds undervoltage protection. |
| Interface | I2C | I2C | Equivalent. |
| Operating Temperature Range | -40°C to 85°C | -40°C to 85°C | Equivalent. |
| Mounting Type | Surface Mount | Surface Mount | Equivalent. |
| Package Case | 15-WFBGA, 15-WLP (1.68x2.45 mm) | 15-XFBGA, 15-DSBGA (1.7x2.6 mm) | BQ27Z746YAHR slightly larger footprint. |
| Typical IC Current (Active) | 24 μA | 20 μA | BQ27Z746YAHR slightly lower active current, beneficial for power-sensitive applications. |
| Typical Sleep/Ship Current | Ship: 5 μA; Hibernate: 18 μA; DeepShip: 0.5 μA | Ship: 10 μA; Sleep: 20 μA; Shutdown: 0.2 μA | MAX17303X+T has lower ship and hibernate currents; BQ27Z746YAHR has lower shutdown current. |
| Absolute Max Input Voltage | 40 V | 40 V | Equivalent. |
| Input Voltage Range | 4.5 V min, 4.2 V max (typ 3.7 V) | 2.0 V min, 6 V max (typ 5.5 V) | BQ27Z746YAHR supports wider input voltage, down to 2.0 V, useful for deeper discharge. |
| Output Current (Max) | 100 mA max (typ 50 mA) | 1000 mA max (typ 500 mA) | BQ27Z746YAHR supports 10x higher output current; important for active load driving. |
| Switching Frequency | 500 kHz min, 2 MHz typ, 5 MHz max | 500 kHz min, 1 MHz typ, 2 MHz max | MAX17303X+T supports higher max switching frequency, potentially allowing smaller passives. |
| Package Size | 3 mm x 3 mm (typ) | 1.7 mm x 2.6 mm (typ) | MAX17303X+T slightly larger but square; BQ27Z746YAHR smaller rectangular. |
| Memory Size (Bytes) | Up to 122 bytes user memory | Not specified | MAX17303X+T provides explicit user memory. |
| Authentication | SHA-256 Authentication, 160-bit secret key | SHA-256 Authentication | Both offer SHA-256 authentication. |
| Age Reporting Methods | Capacity reduction, internal resistance increase, calendar aging | Not explicitly detailed | MAX17303X+T provides detailed aging metrics; BQ27Z746YAHR likely limited. |
| Protection Programmability | Programmable voltage/current/temperature thresholds & timers | Configured via firmware, details not explicit | MAX17303X+T offers more configurable hardware protection thresholds. |
| Temperature Measurement | Internal die temperature + external thermistor on TH pin | Internal + external NTC support | Both support thermistor temperature sensing. |
| Internal Thermistor Accuracy | ±0.5°C (-40°C to +85°C) | ±2°C (typ) | MAX17303X+T offers tighter temperature accuracy. |
| Package Pitch | 0.5 mm | Not explicitly specified | MAX17303X+T pitch known; BQ27Z746YAHR pitch not provided. |
| Quiescent Current (Hibernate) | 18 μA | 20 μA | Comparable; MAX17303X+T slightly better. |
| Quiescent Current (Ship) | 5 μA | 10 μA | MAX17303X+T better for ultra-low power modes. |
| Quiescent Current (Shutdown) | 0.5 μA (typ) | 0.2 μA (typ) | BQ27Z746YAHR lower shutdown current, beneficial for very long shelf life. |
| Sense Resistor Range | 0.005 Ω to 0.02 Ω | 1 mΩ min (typ 10Ω?) | MAX17303X+T supports lower sense resistor values, enabling higher measurement sensitivity. |
| ADC Resolution | Not explicitly stated (high resolution implied) | 16-bit | BQ27Z746YAHR specifies 16-bit ADC resolution. |
| I2C Bus Speed | Up to 400 kHz | Up to 400 kHz | Equivalent. |
| Protection Current Limits | Overcharge up to 5.12 A (programmable) | Overcurrent limits configured in firmware; max unspecified | MAX17303X+T specifies programmable current protection; BQ27Z746YAHR relies on firmware. |
| Output Current Capability | 100 mA max | 1 A max | BQ27Z746YAHR supports higher output current, important for direct gate driving. |
| Thermal Resistance (Junction to Ambient) | 54°C/W (single-layer PCB) | 70°C/W | MAX17303X+T better thermal dissipation on single-layer PCB. |
| Thermal Resistance (Junction to Case) | 8°C/W | 17°C/W | MAX17303X+T has lower junction-to-case thermal resistance, better for thermal management. |
| Package Type | 15-WLP (WFBGA) | 15-DSBGA (XFBGA) | Different package types; affects PCB layout and thermal design. |
| Firmware Task Execution Period | 351 ms active, 1.4 s hibernate | Not specified | MAX17303X+T details firmware timing, useful for power budgeting and responsiveness. |
| SHA Calculation Time | 10 ms typ | Not specified | MAX17303X+T provides explicit SHA timing, useful for authentication latency planning. |
| Manufacturer Part Number | MAX17303X+T | BQ27Z746YAHR | — |
| Datasheet Size (pages) | 157 pages (full datasheet) | Not specified | MAX17303X+T datasheet is comprehensive; TI datasheet size not provided. |
3. Design trade-offs
The MAX17303X+T and BQ27Z746YAHR are both designed for single-cell lithium-ion/polymer battery fuel gauging with integrated protection, but the differences in their protection programmability, output current capability, and power consumption profiles lead to distinct design considerations.
The MAX17303X+T integrates a sophisticated ModelGauge m5 EZ algorithm with programmable protection thresholds for overcurrent, overvoltage, undervoltage, and temperature, allowing OEMs to finely tune protection parameters to the battery chemistry and application requirements. Its very low deep-sleep current (down to 0.02 μA) and low ship mode current (~5 μA) make it highly suitable for ultra-low power applications where battery life during extended storage or low activity is critical. The SHA-256 authentication and multiple aging metrics also enable enhanced battery security and lifecycle tracking. However, its output current capability tops out at 100 mA, which limits its ability to drive larger loads or power external FETs directly.
In contrast, the BQ27Z746YAHR from Texas Instruments supports a wider input voltage range starting as low as 2.0 V, which is advantageous for applications that require operation during deep discharge or with a wider battery voltage window. It can supply up to 1 A output current, which allows it to directly drive higher current loads or external FET gates without additional buffering. Its sleep mode current is slightly higher than MAX17303X+T’s hibernate current but offers a very low shutdown current of 0.2 μA, beneficial for applications that demand extremely low power during long shelf life. Protection thresholds and delays are configured via firmware registers but are less explicitly