My Inquiry
My Account
Texas Instruments BQ2018SN-E1
- Part No.:
- BQ2018SN-E1
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
BQ2018SN-E1.pdf
- Description:
- IC BATT MON MULT-CHEM 1-4C 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:362
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
BQ2018SN-E1 from Texas Instruments is a multifunction charge/discharge counter IC for rechargeable battery state-of-charge (SoC) monitoring. It measures voltage drop across a sense resistor with 12.5µV resolution, integrates internal temperature sensing for self-discharge estimation, and provides 1024-bit NVRAM (128 × 8) for capacity and status storage. It operates in battery packs for portable electronics requiring precise coulomb counting.
For engineers reviewing the BQ2018SN-E1 datasheet, BQ2018SN-E1 pinout, BQ2018SN-E1 application, or BQ2018SN-E1 equivalent, key selection considerations include its single-wire HDQ interface, ±200mV differential current-sense input range, <80µA operating current, REG output for low-cost microregulation, and 8-pin TSSOP/SOIC packaging optimized for tight battery-pack integration.
Technical Context
The BQ2018SN-E1 implements a dynamically balanced voltage-to-frequency converter (VFC) architecture to integrate charge/discharge current over time, using a precision bandgap-referenced oscillator (±3.0% timer accuracy) and internal offset calibration. Its dual-mode operation-<80µA active mode and <10µA sleep mode-enables long-term pack-level monitoring without host intervention.
It relies on an external host controller to manage register maintenance (e.g., clearing DCR/CCR/SCR), interpret counts, and apply OFR-based offset correction. The internal temperature sensor (±2°C typical at 25°C) scales self-discharge count rate exponentially (×2 per +10°C above 25°C), enabling accurate SoC estimation during storage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Current-sense resolution | 12.5µV per hour - enables high-resolution coulomb counting with low-value sense resistors (e.g., 10mΩ yields ~125nA/h sensitivity) |
| Input voltage range (SR1–SR2) | ±200mV - supports bidirectional current measurement for NiCd/NiMH/Li-ion chemistries with polarity detection |
| Operating current | <80µA - allows direct operation from battery cells without burdening standby life |
| Sleep current | <10µA - maintains register backup via RBI while minimizing quiescent drain during idle periods |
| NVRAM size | 1024 bits (128 × 8) - stores 13 bytes of battery capacity/status data plus user fields (chemistry, serial number, date) |
| Temperature sensing | 8-step 10°C scale (0–60°C), ±2°C typical accuracy - directly informs self-discharge compensation algorithm |
| REG output | 3.7V nominal (±200mV) - drives external n-JFET for regulated VCC supply, eliminating need for discrete LDO |
Pinout & Package
Package: 8-pin TSSOP (SN) or narrow SOIC - footprint compatible with space-constrained battery pack layouts between A-size cells or within prismatic cell width.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REG | Regulator output | Drives external n-JFET to generate stable 3.7V supply; eliminates need for external regulator in cost-sensitive designs |
| VCC | Supply voltage input | Accepts 2.8–5.5V (direct battery) or 3.7V ±200mV (REG-derived); supports 3–4 NiCd/NiMH or 1 Li-ion cell |
| VSS | Ground reference | Common return for all analog/digital circuitry; must be low-impedance connection to battery pack ground |
| HDQ | Single-wire serial I/O | Open-drain bidirectional interface; requires external pull-up; enables register access and wake-up signaling with minimal pin count |
| WAKE | Wake-up output | Active-low open-drain signal indicating |VSR| > programmed VWOE threshold; used to alert host of charge/discharge activity |
| SR1, SR2 | Differential current sense inputs | Measure voltage drop across external sense resistor; polarity (SR1 vs. SR2) determines charge/discharge direction |
| RBI | Register backup input | Maintains NVRAM contents when VCC < 2.4V; draws <100nA, enabling capacitor-based backup during deep discharge or short-circuit events |
Key Features
| Feature | Design Value |
|---|---|
| Internal offset calibration | Stores 8-bit two's complement OFR value to cancel up to ±500µV input offset, improving current-measurement linearity and repeatability |
| Dual operating modes | Automatic transition between <80µA active mode and <10µA sleep mode based on HDQ state and VSR activity, extending pack runtime |
| Self-discharge estimation | Uses integrated temperature sensor to scale SCR count rate (1 count/hour @ 25°C, ×2 per +10°C), enabling accurate SoC hold-time prediction |
| Single-wire HDQ interface | Asynchronous return-to-one protocol (≤5 kbps) with BREAK recovery; minimizes interconnect complexity in sealed battery modules |
| REG-regulated supply option | Eliminates external LDO by driving low-threshold n-JFET; reduces BOM cost and PCB area in compact battery management systems |
Applications
| Smart Battery Packs | Portable Medical Devices |
|---|---|
Use Scenario: Integrated into sealed NiMH/Li-ion battery packs for laptops, power tools, or drones to report real-time SoC to host system. IC Role / Device Role / Timing Role: Coulomb counter providing accumulated charge/discharge counts (DCR/CCR), self-discharge (SCR), and timing registers (DTC/CTC) to host MCU. Use Value: Enables accurate fuel-gauge algorithms without external ADC or precision op-amps; NVRAM retains critical data during pack removal or deep discharge. | Use Scenario: Monitoring battery health in portable ECG monitors, infusion pumps, or handheld diagnostic tools where runtime predictability is safety-critical. IC Role / Device Role / Timing Role: Low-power SoC estimator with temperature-compensated self-discharge modeling, interfacing via HDQ to embedded ARM Cortex-M host. Use Value: <10µA sleep current preserves battery reserve during standby; internal oscillator eliminates timing component count; RBI backup ensures data integrity during unexpected power loss. |
| Consumer Electronics Accessories | Industrial Handheld Terminals |
Use Scenario: Embedded in USB-C power banks or wireless headset charging cases to track cycle life and remaining capacity. IC Role / Device Role / Timing Role: Charge/discharge counter with automatic wake-up (WAKE pin) triggered by load insertion or charging event. Use Value: Single-wire HDQ simplifies interconnect in miniaturized enclosures; REG output powers host logic from same battery, reducing component count. | Use Scenario: Battery management in ruggedized barcode scanners or field meters operating across -20°C to +70°C ambient ranges. IC Role / Device Role / Timing Role: Temperature-aware coulomb counter using internal sensor to adjust SCR rate, compensating for accelerated self-discharge in hot environments. Use Value: ±2°C temperature accuracy and ±200mV input range ensure reliable SoC reporting under thermal stress; TSSOP package withstands mechanical shock and reflow cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar charge/discharge counter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ2019SN | Same pinout and register map; adds EEPROM write-protection and enhanced WOE flexibility (7 thresholds vs. 6) | Preferred for new designs requiring robust firmware update protection and finer wake-up sensitivity control | Select BQ2019SN if EEPROM security and programmable wake thresholds are required; BQ2018SN-E1 remains suitable for cost-sensitive legacy integration. |
| MAX1660CSA+ | Different architecture (analog integrator + ADC); 16-bit resolution but no integrated temperature sensor or NVRAM | Requires external µC, ADC, and memory; higher system-level BOM cost and design effort | Choose MAX1660CSA+ only when existing platform mandates SPI interface or when custom analog front-end tuning is needed; BQ2018SN-E1 offers lower integration and faster time-to-market. |
Compared with BQ2019SN, the BQ2018SN-E1 lacks EEPROM write-protection but delivers identical core coulomb-counting performance and pin compatibility. Against MAX1660CSA+, it provides full SoC subsystem integration-including temperature compensation, NVRAM, and single-wire interface-at lower total system cost and reduced layout complexity.
Availability
BQ2018SN-E1 is available at Aetrix Electronics and suitable for smart battery packs, portable medical devices, and industrial handheld terminals requiring stable component supply and long-lifecycle support.
Supply support for BQ2018SN-E1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of leadership in battery management ICs.
The BQ2018SN-E1 belongs to TI's Power Minder™ family of battery fuel-gauge ICs, designed specifically for low-cost, high-accuracy coulomb counting in space-constrained rechargeable battery packs.
FAQ
What is the primary function of the BQ2018SN-E1 in a battery management system?
The BQ2018SN-E1 serves as a dedicated coulomb counter that accumulates charge and discharge current over time using a precision voltage-to-frequency converter. It outputs raw counts (DCR, CCR, SCR) and timing data (DTC, CTC) to an external host controller, which computes state-of-charge. Unlike standalone fuel gauges, the BQ2018SN-E1 does not perform SoC calculation internally-it provides the foundational measurement data with high resolution (12.5µV/h) and low power consumption (<80µA).
How does the BQ2018SN-E1 handle temperature compensation for self-discharge estimation?
The BQ2018SN-E1 uses an internal temperature sensor with ±2°C typical accuracy at 25°C to set the self-discharge count rate (SCR). The SCR increments at 1 count/hour at 20–30°C and doubles every +10°C up to >60°C (reaching 16 counts/hour), while halving every −10°C down to <0°C (0.125 counts/hour). This exponential scaling is implemented in hardware and reflected in the TMP/CLR register, enabling the host to estimate capacity loss during storage without external sensors.
Can the BQ2018SN-E1 operate without an external microcontroller?
No-the BQ2018SN-E1 requires an external host controller for all register maintenance, including clearing DCR/CCR/SCR counters, reading temperature data, applying OFR offset correction, and interpreting counts into usable SoC values. It has no built-in computation engine or firmware; its role is strictly analog-to-digital conversion and accumulation. The host must implement the fuel-gauge algorithm using the BQ2018SN-E1's register outputs via the HDQ interface.
What is the purpose of the REG pin on the BQ2018SN-E1, and how is it used in practice?
The REG pin on the BQ2018SN-E1 is the output of an internal operational transconductance amplifier (OTA) configured to drive an external n-channel JFET (e.g., SST108), generating a regulated 3.7V ±200mV supply for VCC. This eliminates the need for a discrete LDO in cost-sensitive battery packs. When REG is used, VCC must be decoupled with ≥0.1µF ceramic capacitance; unused REG should be left floating or tied to VSS through a 10kΩ resistor per TI design guidelines.
How does the RBI pin maintain data integrity when the main battery voltage drops below operational levels?
The RBI pin on the BQ2018SN-E1 provides register backup power when VCC falls below 2.4V-such as during battery short-circuit, deep discharge, or pack removal. An external capacitor or auxiliary cell connected to RBI supplies <100nA to retain NVRAM contents (including DCR, CCR, SCR, and user data). The BQ2018SN-E1 automatically switches to RBI when VCC drops, ensuring zero data loss without host intervention or additional supervision circuitry.
BQ2018SN-E1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- Power Minder™
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Battery Monitor
- Battery Chemistry:
- Multi-Chemistry
- Number of Cells:
- 1 ~ 4
- Fault Protection:
- -
- Interface:
- HDQ
- Operating Temperature:
- -20°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
BQ2018SN-E1 FAQ
1.How can I place an order for BQ2018SN-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for BQ2018SN-E1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for BQ2018SN-E1 reliable?
The price and inventory of BQ2018SN-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BQ2018SN-E1 is usually 5 days.
3.What payment methods are accepted for BQ2018SN-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BQ2018SN-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BQ2018SN-E1?
BQ2018SN-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BQ2018SN-E1 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for BQ2018SN-E1?
For technical support, including BQ2018SN-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BQ2018SN-E1 requirements.
6.How does Aetrix verify that BQ2018SN-E1 is sourced from the original manufacturer or authorized distributors?
All BQ2018SN-E1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BQ2018SN-E1 meets industry standards.
7.What is the process for return or replacement of BQ2018SN-E1?
All BQ2018SN-E1 units undergo pre-shipment inspection (PSI). If there is an issue with BQ2018SN-E1, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The BQ2018SN-E1 part is unused and in its original packaging.
Return procedure for BQ2018SN-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BQ2018SN-E1 Tags
-
BQ29700DSER
Texas Instruments
-
S-8241ABKMC-GBKT2G
ABLIC Inc.
-
S-8241ABPMC-GBPT2G
ABLIC Inc.
-
BQ27427YZFR
Texas Instruments
-
BQ27426YZFR
Texas Instruments
-
STC3117IJT
STMicroelectronics
-
STC3115IJT
STMicroelectronics
-
BQ76925RGER
Texas Instruments
-
NPM1100-QDAA-R
Nordic Semiconductor ASA
-
BQ27441DRZR-G1A
Texas Instruments
-
STC3115AIQT
STMicroelectronics
-
S-8252AAL-M6T1U
ABLIC Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
