MAX17320X20+T vs BQ27Z746YAHR Battery Fuel Gauge ICs: Detailed Comparison
1. Quick verdict
For multi-cell packs (1 to 4 cells), the MAX17320X20+T is the better choice due to its wider cell count support and integrated fault protections tailored for complex battery systems. For single-cell applications requiring very low sleep and ship mode currents with mature, flexible firmware configurability, the BQ27Z746YAHR stands out, especially where minimizing standby power consumption and detailed current monitoring are priorities.
2. Spec comparison table
| Spec | MAX17320X20+T | BQ27Z746YAHR | Notes |
|---|---|---|---|
| Battery chemistry | Lithium Ion/Polymer | Lithium Ion/Polymer | Equivalent chemistry support. |
| Fault protection | Over Current, Over Temperature, Over/Under Voltage, Short Circuit | Over Current, Over Temperature, Over/Under Voltage, Short Circuit | Equivalent protection features. |
| Function | Fuel Gauge | Fuel Gauge | Same function. |
| Interface | I2C | I2C | Same interface. |
| Mounting type | Surface Mount | Surface Mount | Same mounting. |
| Number of cells supported | 1 to 4 | 1 | MAX17320X20+T supports multi-cell packs (up to 4 cells), BQ27Z746YAHR limited to single-cell. MAX17320X20+T is more versatile for multi-cell designs. |
| Operating temperature range | -40°C to 85°C (TA) | -40°C to 85°C (TA) | Equivalent operating range. |
| Package/case | 30-WLP (2.37 x 2.55 mm) | 15-DSBGA (1.7 x 2.6 mm) | BQ27Z746YAHR has a smaller footprint (15 balls vs 30 balls) and slightly narrower width; better for tight PCBs. |
| Input voltage range (min) | Not specified | 2.0 V | BQ27Z746YAHR supports a low input voltage down to 2.0 V, suitable for deeper discharge monitoring. MAX17320X20+T spec not provided. |
| Input voltage range (max) | Not specified | 6 V | BQ27Z746YAHR max input voltage 6 V; MAX17320X20+T max not specified. |
| Absolute max input voltage | Not specified | 40 V | BQ27Z746YAHR supports high transient voltages up to 40 V, allowing robustness against voltage spikes. |
| ADC resolution | Not specified | 16-bit | BQ27Z746YAHR ADC resolution is 16-bit, providing fine measurement granularity. MAX17320X20+T ADC resolution not specified. |
| I2C bus frequency | Not specified | 400 kHz | BQ27Z746YAHR supports fast I2C at 400 kHz; MAX17320X20+T frequency not provided. |
| Power consumption (sleep mode) | Not specified | 20 µA (typ) | BQ27Z746YAHR has documented low sleep current; MAX17320X20+T data not provided, likely higher due to multi-cell support. |
| Power consumption (ship mode) | Not specified | 10 µA (typ) | BQ27Z746YAHR low ship mode current helps extend battery shelf life. |
| Power consumption (shelf mode) | Not specified | 5 µA (typ) | Same as above. |
| Power consumption (shutdown mode) | Not specified | 0.2 µA (typ) | Very low shutdown current in BQ27Z746YAHR; MAX17320X20+T data unavailable. |
| Supply current (typical) | Not specified | 20 µA (typ) | BQ27Z746YAHR is low current in active mode; MAX17320X20+T data unavailable. |
| Design capacity (typical) | Not specified | 5300 mAh | BQ27Z746YAHR example capacity; MAX17320X20+T supports broad range, no specific capacity given. |
| Design voltage (typical) | Not specified | 4.0 V | BQ27Z746YAHR typical pack voltage; MAX17320X20+T supports up to 4 cells (~16.8 V max). |
| Output current max | Not specified | 1 A | BQ27Z746YAHR supports up to 1 A output current; MAX17320X20+T output current not specified. |
| Overcurrent thresholds | Configured in firmware | Configured in firmware | Both devices allow firmware-configured thresholds. |
| Thermal protection | Over Temperature | Over Temperature | Both have thermal protection. |
| Operating junction temperature | Not specified | -40°C to 85°C | Equivalent thermal range. |
| Package size (mm) | 2.37 x 2.55 | 1.7 x 2.6 | BQ27Z746YAHR smaller footprint, beneficial for compact designs. |
| Pins | 30 (WLP balls) | 15 (DSBGA balls) | MAX17320X20+T has twice the pin count, indicating more signals or integrated functions. |
| ESD rating (HBM) | Not specified | 2000 V | BQ27Z746YAHR has documented ESD protection, useful for handling and ruggedness. |
| Package type | 30-WLBGA | 15-DSBGA | Different package types, affecting PCB layout and assembly. |
| Supply voltage range | Not specified | 2 V to 5 V (typ 5.5 V) | BQ27Z746YAHR supply voltage documented; MAX17320X20+T not specified. |
Notes: Many MAX17320X20+T detailed specs, especially electrical and power parameters, are not explicitly provided in the source data, limiting direct comparison on current consumption, ADC resolution, and voltage ranges.
3. Design trade-offs
The most significant difference is the cell count support: MAX17320X20+T supports 1 to 4 cells, making it suitable for multi-cell battery packs (e.g., in power tools, small e-mobility, or multi-cell consumer electronics), while the BQ27Z746YAHR is limited to single-cell designs. This inherently affects the complexity of the battery management system (BMS) and the firmware required.
Physically, the MAX17320X20+T is packaged in a 30-ball wafer-level BGA (WLP) measuring 2.37x2.55 mm, which is larger and more complex to assemble compared to the BQ27Z746YAHR’s smaller 15-ball DSBGA (1.7x2.6 mm). The higher pin count in MAX17320X20+T allows for more integrated functions or additional sensing lines but demands careful PCB layout and routing. The BQ27Z746YAHR’s smaller package is advantageous for compact, single-cell devices where space is premium.
Firmware complexity and configurability also differ: the BQ27Z746YAHR offers extensive firmware configurability for protection thresholds, timing, and logging, with a 16-bit ADC and detailed current measurement resolution (3.74 µV) enabling precise state-of-charge (SoC) calculations and fault detection. The MAX17320X20+T, while less detailed in the provided data, likely integrates similar or enhanced algorithms optimized for multi-cell packs but may require more complex firmware integration.
Power consumption is critical for battery fuel gauges, especially in low-power devices. The BQ27Z746YAHR documents extremely low currents in sleep (20 µA), ship (10 µA), shelf (5 µA), and shutdown (0.2 µA) modes, making it well-suited for devices that must conserve battery over long periods. The MAX17320X20+T data does not specify these values but generally, multi-cell gauges with more pins and functions tend to have higher quiescent currents.
Thermal considerations are similar, with both devices operating reliably from -40°C to +85°C ambient, but the MAX17320X20+T’s larger package and multiple cell support might result in higher thermal dissipation requirements. The BQ27Z746YAHR’s smaller package and lower power modes simplify thermal design. Neither part specifies gate drive requirements or switching frequencies, as these are fuel gauges, not power switches.
Cost-wise, the MAX17320X20+T with more pins and multi-cell support will be higher per unit and may incur higher PCB assembly costs due to the WLP package and complexity. The BQ27Z746YAHR’s smaller, simpler package reduces cost and assembly complexity, suitable for volume single-cell applications.
4. Use-case fit
Choose MAX17320X20+T when:
- Designing battery packs with 2, 3, or 4 Li-Ion