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Vishay Siliconix SI9730BBY-T1-E3
- Part No.:
- SI9730BBY-T1-E3
- Manufacturer:
- Vishay Siliconix
- Category:
- Battery Management
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SI9730BBY-T1-E3.pdf
- Description:
- IC BATT MFUNC LI-ION 2CELL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,877
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Product details
Overview
SI9730BBY-T1-E3 from Vishay Siliconix is a dual-cell lithium-ion battery protection IC designed for carbon/coke-chemistry 2S packs. It provides over-charge detection at 4.25 V (typ), over-discharge detection at 2.2 V (typ), cell-balancing current of 15 µA (typ), and operates in an SOIC-8 package with -25 °C to +85 °C temperature range. It is used in portable power tools, medical handheld devices, and industrial backup systems requiring precise dual-cell voltage supervision.
For engineers reviewing the SI9730BBY-T1-E3 datasheet, SI9730BBY-T1-E3 pinout, SI9730BBY-T1-E3 application, or SI9730BBY-T1-E3 equivalent, this page delivers verified technical context, real-world design meaning of specifications, validated pin functions, confirmed alternative parts with documented differences, and supply support for legacy EOL components in production continuity programs.
Technical Context
The SI9730BBY-T1-E3 implements ground-side switching via two external source-connected N-channel MOSFETs controlled by its DCO output, which dynamically references either VM (during charge) or VSS (during discharge) to prevent unintended turn-on. Its internal A/D converter monitors individual cell voltages through the VC pin, enabling independent over-charge (VOC1/VOC2 = 4.25 V typ) and over-discharge (VODC1/VODC2 = 2.2 V typ) detection per cell.
It integrates a 15 µA cell-balancing network that bleeds current from overcharged cells until voltage equality is restored, and uses an external CD capacitor to set DL2 timeout (40 ms typ at 500 pF) before disabling charging. The current-limit comparator triggers at 28 mV (typ) across the IS sense resistor with 0.18 %/°C temperature coefficient for copper-trace compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Over-charge threshold | 4.25 V (typ) per cell - sets maximum safe charging voltage for Li-ion carbon/coke chemistry; ±1.19 % accuracy ensures reliable cell-level protection. |
| Over-discharge threshold | 2.2 V (typ) per cell - prevents irreversible capacity loss during load discharge; hysteresis avoids oscillation near trip point. |
| Cell balancing current | 15 µA (typ) - actively equalizes voltage between mismatched cells without external circuitry; enables full pack utilization. |
| Supply current (normal) | 30 µA (typ) - minimizes standby drain on battery; supports long-term storage and low-power monitoring. |
| Current limit threshold | 28 mV (typ) at IS pin - defines short-circuit trip level; scales linearly with external sense resistor for configurable ILIMIT. |
| Operating temperature | -25 °C to +85 °C - validated for industrial portable equipment environments; junction max 125 °C. |
| Package | SOIC-8 (lead-free) - surface-mount compatible with standard reflow profiles; thermal impedance 80 °C/W. |
Pinout & Package
SI9730BBY-T1-E3 is housed in an 8-pin SOIC package (body width 3.9 mm, lead pitch 1.27 mm) with exposed pad not electrically connected. Pin 2 is NC and must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VM | Negative battery pack terminal | Reference node for DCO during charging; connects to external battery negative; senses short-circuit via voltage drop. |
| NC | No connection | Pin 2 is internally unconnected; must be left floating or grounded - no routing or soldering allowed. |
| VDD | Dual-cell positive terminal | Connects to series stack anode; supplies IC power; absolute max 12 V relative to VSS. |
| CD | Delay capacitor connection | Sets DL2 timeout duration (e.g., 40 ms at 500 pF); determines post-overcharge hold time before switch disable. |
| VC | Center-tap voltage monitor | Direct connection to inter-cell node; enables per-cell voltage measurement via internal A/D converter. |
| IS | Current sense comparator input | Monitors voltage across external sense resistor; trips at 28 mV (typ) to detect short-circuit or overcurrent. |
| VSS | Dual-cell negative terminal | Ground reference for IC logic and analog sections; connects to battery cathode; DCO references VSS during discharge. |
| DCO | Low-side MOSFET gate driver | Drives gates of two back-to-back N-MOSFETs; swings from VOL (~0.4 V) to VDD; referenced to VM or VSS depending on mode. |
Key Features
| Feature | Design Value |
|---|---|
| Individual cell voltage monitoring | Separate VOC1/VOC2 and VODC1/VODC2 thresholds enable asymmetric cell protection without shared trip points. |
| Accurate over-charge detection | ±1.19 % tolerance at 4.25 V ensures compliance with Li-ion safety standards while maximizing usable capacity. |
| Low quiescent current | 30 µA operating / 1 µA shutdown current extends battery shelf life and supports always-on monitoring. |
| Internal cell balancing | 15 µA bleed current corrects voltage drift between cells without external FETs or control logic. |
| High noise immunity | Integrated current-sense filtering (RIS/C2) and hysteresis prevent false trips from transient load spikes or EMI. |
Applications
| Power Tools | Medical Handheld Devices |
|---|---|
Use Scenario: Cordless drill/driver with 2S Li-ion pack subject to high-current bursts and thermal cycling. IC Role / Device Role / Timing Role: Dual-cell protector enforcing per-cell over-charge (4.25 V) and over-discharge (2.2 V) limits; initiates 15 µA balancing during charge termination. Use Value: Prevents cell imbalance-induced capacity loss and thermal runaway during repeated high-C-rate cycles. |
Use Scenario: Portable ultrasound or infusion pump requiring >2-year shelf life and fail-safe battery disconnect. IC Role / Device Role / Timing Role: Low-quiescent (30 µA) supervisor detecting open-center-tap faults and entering 1 µA UVL shutdown below 3.7 V. Use Value: Eliminates parasitic drain during storage while guaranteeing immediate protection upon first use. |
| Industrial Backup Systems | Consumer Drones |
Use Scenario: Uninterruptible power module for PLC I/O with wide ambient (-25 °C to +85 °C) operation. IC Role / Device Role / Timing Role: Temperature-compensated (0.18 %/°C) current-limit comparator interfacing with copper trace sense resistor. Use Value: Maintains accurate short-circuit trip point across operating range without calibration or trimming. |
Use Scenario: 2S Li-ion battery in compact FPV drone experiencing vibration-induced center-tap disconnection. IC Role / Device Role / Timing Role: Open-center-tap detector forcing switch-off until VC reconnection; allows safe 1/8-duty-cycle charging if undervoltage present. Use Value: Avoids catastrophic failure from mechanical battery pack failure while preserving recharge capability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-cell lithium-ion protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| R5640T202AA-TR | 4.25 V over-charge threshold (same), but uses internal sense FET; no external IS resistor required. | Eliminates sense resistor layout and power loss; unsuitable where external current sensing is mandated for redundancy. | Prefer when board space is constrained and integrated FET reliability meets system SIL requirements. |
| BQ77PL900DWR | Programmable thresholds (4.1–4.35 V), higher accuracy (±0.5 %), but requires I²C configuration and external MCU. | Enables dynamic threshold adjustment for aging compensation; adds firmware dependency and BOM complexity. | Choose when adaptive protection and telemetry logging are required; avoid for cost-sensitive fixed-threshold designs. |
Compared with SI9730BBY-T1-E3, R5640T202AA-TR reduces component count by integrating the sense FET, while BQ77PL900DWR trades simplicity for programmability and precision-neither offers pin compatibility, and both require PCB redesign and firmware integration.
Availability
SI9730BBY-T1-E3 is available at Aetrix Electronics and suitable for industrial backup systems, medical handheld devices, and power tools requiring stable component supply despite end-of-life status.
Supply support for SI9730BBY-T1-E3 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
Vishay Siliconix is a global semiconductor manufacturer specializing in discrete power MOSFETs, diodes, optoelectronics, and analog ICs for industrial, automotive, and computing applications.
The Si9730 product line was engineered specifically for dual-cell lithium-ion battery pack protection, emphasizing accuracy, ultra-low quiescent current, and robust fault handling in space-constrained portable equipment.
FAQ
What is the over-charge detection voltage for SI9730BBY-T1-E3?
The SI9730BBY-T1-E3 has a typical over-charge detection threshold of 4.25 V per cell (VOC1/VOC2), with ±1.19 % accuracy at 25 °C and guaranteed 4.15 V to 4.25 V range across -25 °C to +85 °C. This value is fixed for the "B" suffix variant and applies independently to each cell monitored via the VC pin.
Does SI9730BBY-T1-E3 support cell balancing, and how does it work?
Yes, SI9730BBY-T1-E3 provides active cell balancing with a typical current of 15 µA. When one cell exceeds the over-charge threshold while the other remains below it, the IC bleeds current from the overcharged cell through an internal network tied to the VC pin until both cells reach equal voltage - no external FETs or control logic are needed.
What package type and lead finish does SI9730BBY-T1-E3 use?
SI9730BBY-T1-E3 is supplied in an 8-pin SOIC package with lead-free (Pb-free) finish, compliant with RoHS Directive 2011/65/EU. The "-E3" suffix explicitly denotes the lead-free variant, and the package dimensions match JEDEC MS-012AC standard (body width 3.9 mm, lead pitch 1.27 mm).
Is SI9730BBY-T1-E3 still in production, and what is its lifecycle status?
SI9730BBY-T1-E3 is End of Life (EOL) with last available purchase date of December 31, 2014. Aetrix Electronics maintains traceable inventory and supports continuity programs for legacy designs, including obsolescence mitigation, cross-reference validation, and extended lifecycle coordination.
How does SI9730BBY-T1-E3 handle short-circuit detection and recovery?
SI9730BBY-T1-E3 detects short circuits by monitoring voltage at the IS pin; if it exceeds 28 mV (typ), the DCO output disables the external MOSFETs. Recovery requires removal of the short, confirmed by IVMSHORT current (30–300 µA) shifting VM voltage - only then does the IC re-enable the switch, preventing automatic retry under fault conditions.
SI9730BBY-T1-E3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Siliconix
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Multi-Function Controller
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 2
- Fault Protection:
- Over Current, Under Voltage
- Interface:
- -
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
SI9730BBY-T1-E3 FAQ
1.How can I place an order for SI9730BBY-T1-E3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SI9730BBY-T1-E3 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 SI9730BBY-T1-E3 reliable?
The price and inventory of SI9730BBY-T1-E3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SI9730BBY-T1-E3 is usually 5 days.
3.What payment methods are accepted for SI9730BBY-T1-E3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SI9730BBY-T1-E3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SI9730BBY-T1-E3?
SI9730BBY-T1-E3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SI9730BBY-T1-E3 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 SI9730BBY-T1-E3?
For technical support, including SI9730BBY-T1-E3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SI9730BBY-T1-E3 requirements.
6.How does Aetrix verify that SI9730BBY-T1-E3 is sourced from the original manufacturer or authorized distributors?
All SI9730BBY-T1-E3 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 SI9730BBY-T1-E3 meets industry standards.
7.What is the process for return or replacement of SI9730BBY-T1-E3?
All SI9730BBY-T1-E3 units undergo pre-shipment inspection (PSI). If there is an issue with SI9730BBY-T1-E3, 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 SI9730BBY-T1-E3 part is unused and in its original packaging.
Return procedure for SI9730BBY-T1-E3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SI9730BBY-T1-E3 Tags
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