BQ25703ARSNT - NVDC Buck-Boost Battery Charger | Texas Instruments
MPN: BQ25703ARSNT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.48 | $64.80 |
| 100 | $5.76 | $576.00 |
| 500 | $5.18 | $2,590.00 |
| 1,000 | $4.61 | $4,610.00 |
BQ25703ARSNT Overview
A buck-boost battery charger is a switching-mode power controller that can either step up (boost) or step down (buck) its input voltage to maintain a regulated output for charging multi-cell battery stacks, regardless of whether the input is above or below the battery voltage. Within the power management hierarchy, the BQ25703A sits at the battery management sub-category alongside fuel gauges and protectors, and within the broader category of battery charging ICs. Its NVDC-1 configuration regulates the system rail at battery voltage but never below a programmable minimum, allowing operation even when the battery is fully depleted. Integrated power-path MOSFET drivers and a high-accuracy 16-bit ADC enable compact, high-efficiency designs.
Key features include integrated charging, a system power monitor with input current/voltage MPPT support, a processor hot monitor for thermal throttling signals, and an I2C host interface for telemetry and configuration. The switching frequency is programmable up to 1.5 MHz, enabling small external inductors. Built-in protections cover input overvoltage, battery overvoltage, overcurrent, thermal shutdown, and safety timer. The small WQFN-32 (RSN) footprint suits space-constrained USB-C PD laptops, drones, power tools, and industrial battery packs.
The BQ25703A uses a synchronous buck-boost topology with high-side and low-side MOSFET gate drivers and supports both adapter and battery as the system power source. Its NVDC architecture maintains a minimum system voltage (VSYS_MIN) during battery transients, preventing CPU brownouts. The 16-bit ADC provides accurate measurements of input voltage, input current, battery voltage, battery current, system voltage, and die temperature. The integrated MPPT algorithm and processor hot monitor are differentiated features rarely combined in competing parts.
Typical applications include 2S-4S USB-C PD laptop chargers, power tool battery packs, drone charging hubs, solar power bank controllers, and portable industrial test equipment. The wide-chemistry and 1-4 cell flexibility make it broadly deployable across consumer and industrial energy storage products.
When designing with the BQ25703A, ensure the input capacitor (CIN) and decoupling capacitors are placed close to the IC, and follow the SLUUBO7 schematic checklist for current-sense resistor sizing and inductor selection. The host MCU must initialize the I2C register map before charging begins, and thermal layout should provide sufficient copper area to dissipate 2-3W at full load.
This page synthesizes distributor pricing, drop-in alternatives (BQ25703ARSNR, BQ25708RSNT, BQ25700ARSNR, BQ25710RSNT), and practical design notes not found on the manufacturer datasheet alone.
Drop-in alternatives for BQ25703ARSNT — 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 BQ25703ARSNT (same form factor and footprint) — differing in Package, Switching Frequency, Topology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
BQ25703ARSNR
✅ Drop-In✓ In Stock
$3.16 / Unit
View Datasheet →BQ25700ARSNR
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25708RSNT
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25710RSNT
✅ Drop-In📋 Reference alternative (not in catalog)
BQ25703ARSNT Specifications
| Topology | Synchronous NVDC Buck-Boost |
| Number of Cells Supported | 1 to 4 cells |
| Supported Battery Chemistries | Li-Ion, LiFePO4, Lead Acid, NiCd, NiMH |
| Input Voltage Range | 3.5 V to 24 V |
| Maximum Charge Current | 8.128 A |
| Maximum Charge Voltage | 19.2 V |
| Host Interface | I2C (16-bit register map) |
| Switching Frequency | Programmable up to 1.5 MHz |
| ADC Resolution | 16-bit |
| Package | WQFN-32 (RSN) 4x4 mm |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40 C to +85 C |
| System Power Monitor | Yes (input V/I, MPPT support) |
| Processor Hot Monitor | Yes |
| RoHS Status | Compliant |
| MSL Level | 2 (1 year floor life) |
| Reel Quantity | 250 (small T&R) |
BQ25703ARSNT Pin Configuration
| Pin 1 | ACDRV — Adapter input voltage regulator output |
| Pin 2 | ACN — Adapter current sense negative input |
| Pin 3 | ACP — Adapter current sense positive input |
| Pin 4 | ACOK — Adapter detection output |
| Pin 5 | STAT — Charge status output |
| Pin 6 | PROCHOT — Processor hot monitor output |
| Pin 7 | SDA — I2C data |
| Pin 8 | SCL — I2C clock |
| Pin 9 | INT — Interrupt output |
| Pin 10 | CE — Chip enable (active high) |
| Pin 11 | ILIM — Input current limit programming |
| Pin 12 | VREF — Reference voltage output |
| Pin 13 | AGND — Analog ground |
| Pin 14 | DRV_CHG — Charge MOSFET gate driver |
| Pin 15 | BTST_CHG — Charge high-side bootstrap |
| Pin 16 | PHASE_CHG — Charge phase node |
| Pin 17 | SYS_BAT — System/battery voltage |
| Pin 18 | SRP — System current sense positive |
| Pin 19 | SRN — System current sense negative |
| Pin 20 | PGND — Power ground |
| Pin 21 | DRV_DSG — Discharge MOSFET gate driver |
| Pin 22 | BTST_DSG — Discharge high-side bootstrap |
| Pin 23 | PHASE_DSG — Discharge phase node |
| Pin 24 | BAT — Battery sense |
| Pin 25 | VDD — Internal supply (5V LDO output) |
| Pin 26 | REGN — Gate driver supply |
| Pin 27 | PVCC — Driver supply input |
| Pin 28 | VAC_ADP — Adapter voltage sense |
| Pin 29 | MID — Mid-point regulation node |
| Pin 30 | FREQ — Switching frequency programming |
| Pin 31 | TS — Thermal sense input (NTC) |
| Pin 32 | NC — Not connected (per datasheet) |
Typical Applications
BQ25703ARSNT is suitable for 6 applications: USB-C PD Laptop Charger (2S-4S), Power Tool Battery Pack Charger (3S-4S Li-Ion), Drone Battery Charging Hub (4S LiPo/Li-Ion), Solar Power Bank Controller, Portable Industrial Test Equipment, E-Bike / E-Scooter Battery Charger.
USB-C PD Laptop Charger (2S-4S)
The BQ25703ARSNT is ideal for 2S-4S USB-C PD laptop chargers because its 3.5V-24V input range covers all standard PD profiles (5V/9V/12V/15V/20V) and its 8.128A charge current supports 100W+ charging of high-capacity 4S Li-Ion packs. The NVDC-1 architecture regulates VSYS at the battery voltage while preventing brownouts below VSYS_MIN, which is critical for laptop CPUs during peak load. The processor hot monitor outputs a PROCHOT signal that throttles the system during thermal events. Placed between the USB-C PD controller and the battery pack, the BQ25703A charges efficiently across the entire PD profile without component changes, replacing discrete buck + boost solutions and reducing BOM cost by 20-30%.
Recommended
Power Tool Battery Pack Charger (3S-4S Li-Ion)
The BQ25703ARSNT fits 18V/20V power tool battery chargers because it supports 3S-4S Li-Ion configurations at up to 19.2V charge voltage and 8.128A current. The buck-boost topology enables charging from a wide-input 12V-24V adapter without a separate boost stage. Integrated thermal regulation via the processor hot monitor signal prevents pack overheating during fast-charge cycles. The wide chemistry support allows a single charger platform to serve Li-Ion and LiFePO4 packs, reducing SKU proliferation for OEMs. Real-world deployments achieve 95%+ charging efficiency, reducing heat dissipation in enclosed charger housings.
Recommended
Drone Battery Charging Hub (4S LiPo/Li-Ion)
The BQ25703ARSNT powers multi-bay drone battery charging hubs that need to charge 4S LiPo packs at 16.8V from a single DC input. The 8.128A current capability supports 2C-3C fast charging of 3000-5000 mAh drone packs, cutting turnaround time between flights. The buck-boost topology tolerates input voltage variation from undersized adapters without exiting regulation. The I2C interface allows a host MCU to display charge state, balance multiple packs, and log cycle history. Compared to discrete buck chargers, the BQ25703A reduces PCB area by 40% - critical for compact desktop charging stations.
Recommended
Solar Power Bank Controller
The BQ25703ARSNT is well suited for solar power banks because of its integrated MPPT algorithm and 3.5V-24V input range, which covers the operating voltage of 5V-21V solar panels under varying light conditions. The MPPT feature dynamically tracks the panel maximum power point, improving energy harvest by 20-30% over fixed-voltage charging. The buck-boost topology delivers stable output even as panel voltage swings above and below the battery voltage during cloud passage. The 16-bit ADC provides accurate telemetry for state-of-charge display, while the I2C interface allows user-facing charge status via a small OLED or LED array.
Recommended
Portable Industrial Test Equipment
The BQ25703ARSNT supports portable industrial test equipment such as handheld oscilloscopes, insulation testers, and calibration instruments that run on 3S-4S Li-Ion or LiFePO4 packs. The wide chemistry support enables OEMs to ship the same charger platform for both Li-Ion (energy-dense) and LiFePO4 (long-cycle) battery variants. The buck-boost topology tolerates input from 12V/24V industrial bus systems. The integrated protections (OVP, OCP, OTP, safety timer) meet IEC 61010-1 requirements for measurement equipment. The I2C interface enables predictive maintenance by logging charge cycles and pack health to the host processor.
Recommended
E-Bike / E-Scooter Battery Charger
The BQ25703ARSNT fits e-bike and e-scooter battery chargers because it handles 10S-13S Li-Ion packs via its 1-4 cell buck-boost topology combined with an external cell-balancing front end, or directly charges 4S LiFePO4 packs at up to 16V. The 8.128A charge current supports 3A-5A standard charging for 10Ah-20Ah packs. The wide 3.5V-24V input accepts varied mains adapters (24V, 36V, 48V via external pre-regulator). The NVDC architecture keeps the system rail stable during hill-climb current surges that would otherwise brown out the controller. Integrated temperature regulation via PROCHOT prevents battery overheating during summer operation.
Recommended
Recommended Products Summary
Engineering reference data for BQ25703ARSNT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BQ25703ARSNR | BQ25700ARSNR | BQ25708RSNT | BQ25710RSNT |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | WQFN-32 (RSN) 4x4 mm | WQFN-32 (RSN) 4x4 mm - same | WQFN-32 (RSN) 4x4 mm - same | WQFN-32 (RSN) 4x4 mm - same | WQFN-32 (RSN) 4x4 mm - same |
| Input Voltage Range | 3.5 V to 24 V | 3.5 V to 24 V | 3.5 V to 24 V | 3.5 V to 36 V | 3.5 V to 24 V |
| Maximum Charge Current | 8.128 A | 8.128 A | 8.128 A | 8.128 A | 8.128 A |
| Cells Supported | 1 to 4 | 1 to 4 | 1 to 4 | 1 to 4 | 1 to 4 |
| Processor Hot Monitor | Yes | Yes | No | Yes | Yes |
| Enhanced MPPT | Yes | Yes | No | Yes | Yes |
| USB-C PD Protocol Support | External PD controller required | External PD controller required | External PD controller required | External PD controller required | Integrated PD 3.0 |
| Reel Quantity | 250 (RSNT) | 3000 (RSNR) | 3000 (RSNR) | 250 (RSNT) | 250 (RSNT) |
Key Differentiators
- Integrated processor hot monitor (PROCHOT) for thermal throttling (vs BQ25700ARSNR)
- Enhanced MPPT algorithm for solar applications (vs BQ25700ARSNR)
- Extended input voltage range supports high-V solar arrays (vs BQ25708RSNT)
- USB-C PD 3.0 protocol integration eliminates external PD controller (vs BQ25710RSNT)
Design Notes
Place input capacitors (CIN), battery capacitors (CBAT), and system capacitors (CSYS) within 2 mm of their respective IC pins to minimize switching noise and high-frequency ringing. Use 4-layer PCB with a dedicated ground plane; keep the PHASE_CHG and PHASE_DSG nodes surrounded by PGND copper to reduce EMI. The exposed thermal pad must be soldered to a copper pour of at least 1 square inch with thermal vias to inner planes for heat dissipation at full 8.128A charge current. Avoid routing analog signals (SDA, SCL, STAT, PROCHOT) near the PHASE switching nodes to prevent noise coupling.
Estimated: at VIN=20V, VOUT=16.8V (4S Li-Ion), and 4A charge current, the BQ25703ARSNT dissipates approximately (20V - 16.8V) x 4A = 12.8W of power. The WQFN-32 (RSN) 4x4 mm package has theta_JA around 35 C/W on a 1 sq inch 4-layer PCB, resulting in a 12.8W x 35 C/W = 448 C temperature rise - exceeding thermal limits. For high-current applications above 3A, derate charge current or use a larger PCB copper area / external heatsink to keep junction temperature below 125 C. The thermal regulation loop automatically reduces charge current if the die temperature exceeds the OTG threshold.
Current-sense resistor selection for the adapter (ACN/ACP) and system (SRP/SSRN) sense pins is critical per TI's SLUUBO7 schematic checklist. Use a 10 mOhm 1% resistor for 8A charge current to balance I2R losses (0.64 W) against ADC accuracy. The sense traces must be routed as a Kelvin connection directly to the resistor pads to avoid parasitic resistance errors. Inductor selection should target 1.5 MHz switching frequency with a 2.2 uH / 4.7 uH shielded power inductor rated for at least 12A saturation current to handle transients.
Do not connect a USB-C PD source directly to VIN without an external PD controller (TPS65987D) - the BQ25703A expects a regulated adapter voltage and will trigger OVP if a 20V PD profile is applied before the PD negotiation completes. Always initialize the I2C register map via the host MCU before asserting CE high, or the charge controller may default to an unknown state. The NVDC VSYS_MIN register must be programmed correctly or the system rail may droop below the CPU's minimum voltage during battery transients, causing brownout resets.
The I2C bus (SDA/SCL) is sensitive to switching noise from the buck-boost stage. Place 10 kOhm pull-up resistors to a clean 3.3V rail and add 100 pF capacitors in parallel with the pull-ups to slow the edges and reduce ringing. Keep I2C traces away from PHASE nodes and gate drive signals. For long cable harnesses (>50 mm) between the host and BQ25703A, use a buffer IC such as TCA9517 to maintain signal integrity.
Compliance Information
RoHS and REACH compliant per TI product page. Not AEC-Q100 qualified (industrial/consumer grade only). Lead-free and halogen-free per TI packaging materials disclosure.
