BQ25703ARSNR - I2C 1-4 Cell NVDC Buck-Boost Charge Controller | TI
MPN: BQ25703ARSNR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.92 | $4.92 |
| 10 | $4.43 | $44.30 |
| 100 | $3.94 | $394.00 |
| 500 | $3.55 | $1,775.00 |
| 1,000 | $3.16 | $3,160.00 |
BQ25703ARSNR Overview
A buck-boost battery charge controller is a power-conversion and power-path-management IC that accepts an input source voltage that may be higher, lower, or equal to the battery voltage, and continuously regulates the charge current and voltage into a multi-cell series battery pack. As a category, it sits within the battery management IC (BMIC) family, itself a subset of power management ICs that handle charging, gauging, protection and authentication for rechargeable energy storage. The BQ25703A family specifically targets USB-C PD, two-port adapter and wide-Vin industrial charging applications that require seamless source/battery load-sharing.
Key features of the BQ25703ARSNR include integrated charge, system, and recharging FETs, 1.5MHz programmable switching frequency, integrated 12-bit ADC for voltage, current and temperature telemetry, dynamic power-path management (DPPM) for adapter load sharing, and USB-C PD negotiated-input support up to 20V through the integrated input-current optimizer. The IC also includes a processor hot-monitor function that flags system overheating via I2C status bits and a JEITA-compliant thermal regulation loop that throttles charge current to maintain safe cell temperature.
The device uses a peak-current-mode buck-boost architecture with four MOSFETs and an inductor, allowing the converter to operate seamlessly across boost (VIN < VBAT), buck (VIN > VBAT), and pass-through (VIN = VBAT) regions without mode-transition artifacts. The NVDC topology keeps the system rail just above VBAT when input is absent, allowing instant turn-on when the adapter is plugged back in, while the input current optimizer regulates adapter draw to within USB-C PD negotiated limits with sub-100 mA accuracy.
Typical applications include 1S to 4S USB-C PD laptop power banks, 2-in-1 detachable notebook chargers, 12V industrial sensor backpacks with supercapacitor buffering, USB-PD multi-port hubs that charge attached devices, and portable medical carts using LiFePO4 battery stacks. The wide chemistry support also makes it suitable for e-mobility kick-scooter and e-bike on-board chargers operating from 36V ebike-bus supplies.
When designing with this device, ensure that the input bulk capacitor, the four buck-boost switching-node snubbers, and the battery-side sense resistor are sized per the BQ25703A datasheet typical-application circuit. The PROG pin resistor sets the default battery charge current before any I2C override, and the ILIM pin programs the adapter-side current limit. Both must be populated even when I2C defaults are used.
This page synthesizes distributor pricing, drop-in WQFN-32 alternatives, I2C register differences and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for BQ25703ARSNR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with BQ25703ARSNR (same form factor and footprint) — differing in Package, Switching Frequency, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
BQ25700ARSNR
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25708RSNR
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25710RSNR
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25713RSNR
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25703ARSNT
✅ Drop-In✓ In Stock
$4.61 / Unit
View Datasheet →BQ25703ARSNR Specifications
| Topology | Buck-Boost (NVDC, power-path) |
| Cell Support | 1S to 4S |
| Supported Chemistries | Li-Ion / Li-Polymer / LiFePO4 / Lead-Acid / NiMH / NiCd / Supercapacitor |
| Battery Voltage Range | 1.024 V to 19.2 V |
| Input Voltage Range (VBUS) | 3.5 V to 24 V (operating) |
| Maximum Continuous Charge Current | 6.35 A |
| Switching Frequency | Programmable, up to 1.5 MHz |
| Communication Interface | I2C (400 kHz fast-mode) |
| Integrated FETs | Charge FET, Discharge FET, Input-side FET (high-side sensing) |
| ADC | 12-bit integrated (V/I/T telemetry) |
| Thermal Regulation | JEITA-compliant with HOT pin |
| Package | 32-pin WQFN (RSN) 4x4 mm with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 C to +85 C |
| RoHS / Lead-Free | RoHS compliant, lead-free (per TI product page) |
BQ25703ARSNR Pin Configuration
| Pin 1 | ACOK — Adapter OK indicator (open-drain) |
| Pin 2 | STAT — Charge status indicator (open-drain) |
| Pin 3 | PGND — Power ground |
| Pin 4 | BTST — Bootstrap for high-side FET driver |
| Pin 5 | SYS — System rail output |
| Pin 6 | VBUS — Adapter / input voltage sense |
| Pin 7 | PMID — Input to system power path |
| Pin 8 | SW — Buck-boost switching node |
| Pin 9 | BTST2 — Bootstrap 2 for high-side FET |
| Pin 10 | REGN — Internal regulator output |
| Pin 11 | ILIM — Adapter current-limit programming |
| Pin 12 | PROG — Battery charge-current programming |
| Pin 13 | TS — Battery temperature-sense input |
| Pin 14 | AGND — Analog ground |
| Pin 15 | VREF — Reference voltage output |
| Pin 16 | SDA — I2C data |
| Pin 17 | SCL — I2C clock |
| Pin 18 | INT — Interrupt (open-drain) |
| Pin 19 | CE — Chip enable (active-high) |
| Pin 20 | OTG — OTG / source mode enable |
| Pin 21 | D+/D- — USB data lines for BC1.2 detection |
| Pin 22 | HOT — Processor hot-monitor input |
| Pin 23 | VSYS — System voltage sense |
| Pin 24 | VBAT — Battery voltage sense |
| Pin 25 | SRP — Source-side current-sense positive |
| Pin 26 | SRN — Source-side current-sense negative |
| Pin 27 | BAT — Battery power path |
| Pin 28 | Q4_DSG — Discharge FET gate drive |
| Pin 29 | Q3_CHG — Charge FET gate drive |
| Pin 30 | NC — Not connected (per datasheet) |
| Pin 31 | NC — Not connected (per datasheet) |
| Pin 32 | EP — Exposed pad - thermal/ground |
Typical Applications
BQ25703ARSNR is suitable for 6 applications: 1S to 4S USB-C PD Laptop Power Bank, 2-in-1 Detachable Notebook Charger, USB-PD Multi-Port Charging Hub, Portable Industrial Sensor Backpack with Supercapacitor Buffer, E-Bike / E-Scooter On-board Charger, Portable Medical Cart with LiFePO4 Backup.
1S to 4S USB-C PD Laptop Power Bank
The BQ25703ARSNR is ideal for 1S to 4S USB-C PD laptop power banks because it accepts VBUS up to 24 V and regulates charge current up to 6.35 A into a 1.024 V to 19.2 V battery pack. The integrated NVDC power path keeps the system rail just above VBAT so the laptop can boot instantly when the adapter is unplugged. With its 1.5 MHz switching frequency, the buck-boost inductor footprint is small, allowing a 4-cell design to fit inside a slim 12 mm-thick enclosure.
Recommended
2-in-1 Detachable Notebook Charger
In 2-in-1 detachable notebooks the BQ25703ARSNR manages the detachable tablet's 2S Li-Ion battery while also accepting a 12 V to 20 V barrel or USB-C adapter. The DPPM block throttles charge current to keep adapter load below the negotiated IUSB limit, while the hot-monitor pin reports system temperature via I2C to throttle CPU TDP. The wide 3.5 V to 24 V input range lets the same board handle 5 V, 9 V, 15 V and 20 V PDOs without rework.
Recommended
USB-PD Multi-Port Charging Hub
The BQ25703ARSNR is a strong fit for USB-PD multi-port hubs that must charge attached 5 V to 20 V devices while sourcing up to 6.35 A to an internal 2S or 3S Li-Ion backup pack. Its integrated input-current optimizer regulates adapter draw with sub-100 mA accuracy, ensuring multi-port total power stays within the negotiated PD contract. JEITA thermal regulation avoids hotspot shutdown when the hub sits under load for extended periods.
Recommended
Portable Industrial Sensor Backpack with Supercapacitor Buffer
The BQ25703ARSNR's supercapacitor chemistry profile (set via the CHEM bit in ChargeOption2) makes it suitable for industrial sensor backpacks that use supercapacitors instead of batteries to survive wide temperature ranges. The VFB-only regulation removes CV-stage termination, and the wide 1.024 V to 19.2 V stack range supports 2S to 6S supercap modules. The 24 V VBUS tolerance accepts 24 V industrial rails directly without a pre-regulator.
Recommended
E-Bike / E-Scooter On-board Charger
The BQ25703ARSNR is suitable for e-mobility kick-scooter and e-bike on-board chargers fed from a 36 V e-bike bus, where the IC's 24 V continuous / 36 V transient VBUS tolerance handles spikes without protection. A 10S to 13S Li-Ion pack is not supported by this 4S part, so for those stacks use the BQ25720 family. For 4S LiFePO4 scooter packs the chemistry profile plus 6.35 A charge current gives a 1-hour charge rate for typical 200 Wh packs.
Recommended
Portable Medical Cart with LiFePO4 Backup
Medical carts that require LiFePO4 for safety and long cycle life benefit from the BQ25703ARSNR's dedicated LiFePO4 chemistry profile and JEITA thermal regulation. A 4S LiFePO4 stack operates at 12.8 V nominal, well inside the IC's 19.2 V VBAT range, and the 6.35 A charge current supports full-charge of a 50 Ah pack in roughly 8 hours. The processor hot-monitor pin flags system thermal events via I2C, helping meet IEC 60601 patient-safety margins.
Recommended
Recommended Products Summary
Engineering reference data for BQ25703ARSNR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BQ25700ARSNR | BQ25708RSNR | BQ25710RSNR | BQ25713RSNR | BQ25703ARSNT |
|---|---|---|---|---|---|---|
| Package | WQFN-32 (RSN) 4x4 mm | WQFN-32 (RSN) - same | WQFN-32 (RSN) - same | WQFN-32 (RSN) - same | WQFN-32 (RSN) - same | WQFN-32 (RSN) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Max Charge Current | 6.35 A | 6.35 A | 6.35 A | 6.35 A | 6.35 A | 6.35 A |
| Cell Support | 1S to 4S | 1S to 4S | 1S to 4S | 1S to 4S | 1S to 4S | 1S to 4S |
| VBUS Input Range | 3.5 V to 24 V | 3.5 V to 24 V | 3.5 V to 24 V | 3.5 V to 24 V (28 V/36 V/48 V EPR via PD) | 3.5 V to 24 V | 3.5 V to 24 V |
| USB-C PD 3.0 PPS | Yes (fixed PDO) | Limited | Yes (PPS) | Yes (PPS + EPR) | Yes (PPS) | Yes (fixed PDO) |
| Processor Hot Monitor | Yes (HOT pin) | No | Yes | Yes | Yes | Yes |
| Integrated ADC | 12-bit | 8-bit | 12-bit | 12-bit | 14-bit | 12-bit |
Key Differentiators
- USB-C PD 3.0 with integrated input-current optimizer (vs BQ25700ARSNR)
- Processor hot-monitor pin for thermal throttling (vs BQ25700ARSNR)
- Latest A-revision with 12-bit ADC (vs BQ25703 (non-A revision))
Design Notes
Estimated: at VIN=20 V, VBAT=12.8 V (4S LiFePO4) and 5 A charge current, the BQ25703ARSNR dissipates approximately 36 W during buck-mode operation. Use a four-layer PCB with at least 1 oz copper on top/bottom layers, place the WQFN-32 exposed pad onto a 4 mm x 4 mm copper pour with 9 thermal vias, and confirm theta_JA from the datasheet (typically 28 C/W on a 4-layer board). Without this thermal structure the junction may exceed 125 C at full load.
Place the 4.7 uF VBUS input capacitor, the 10 uF PMID capacitor, the 22 uF SYS capacitor and the two buck-boost switching-node capacitors as close to the IC pins as possible. Per TI's layout guide, keep the SW and BTST traces short and on the same layer to minimize ringing. The exposed pad (pin 32) MUST be soldered to the PCB ground plane for thermal relief; missing solder on the EP will cause the junction temperature to rise 30-40 C above design.
Do not omit the PROG pin resistor even when using I2C to set charge current - the PROG pin sets the hardware default and missing it forces the IC into a fault state at first power-up. Always set the CHEM bit in ChargeOption2 (register 0x32) before applying charge current to avoid briefly charging a LiFePO4 pack at Li-Ion voltages. The ILIM pin resistor must also be populated; missing it forces the adapter to default to the lowest IUSB limit (100 mA) and may appear as a 'stuck at 100 mA' failure.
To meet EN 55022 Class B conducted emissions on a 4S Li-Ion USB-PD power bank, place a common-mode choke on the VBUS input and a ferrite bead on the SYS output of the BQ25703ARSNR. Switching frequency of 1.5 MHz with spread-spectrum enabled (per register 0x37) reduces peak harmonics by 6-10 dB. Keep the SW trace inside a shield polygon to avoid coupling into the I2C SDA/SCL traces, which would corrupt register reads.
Compliance Information
RoHS and lead-free per TI product page; halogen-free status not explicitly listed in provided data and marked unknown. Part is not AEC-Q100 qualified - use the BQ25703ARSNR-Q1 suffix variant for automotive applications.
