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Texas Instruments UCC3957M-2
- Part No.:
- UCC3957M-2
- Manufacturer:
- Texas Instruments
- Category:
- Battery Management
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
UCC3957M-2.pdf
- Description:
- IC BATT PROT LI-ION 3-4CL 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,245
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Product details
Overview
UCC3957M-2 from Texas Instruments is a BiCMOS lithium-ion battery pack protector IC for three- or four-cell stacks, featuring 4.25 V nominal overvoltage threshold, two-tier overcurrent protection with programmable blanking times, and 3.5 µA sleep-mode supply current. It controls external P-channel MOSFETs to prevent overcharge, overdischarge, and short-circuit damage in portable power systems.
For engineers reviewing the UCC3957M-2 datasheet, UCC3957M-2 pinout, UCC3957M-2 application, or UCC3957M-2 equivalent, this page delivers verified functional identity, confirmed 16-pin SSOP package mapping, validated terminal roles, exact overvoltage/undervoltage thresholds per variant, and real-world smart discharge behavior under overcharge hysteresis.
Technical Context
The UCC3957M-2 implements a continuous internal state machine that independently monitors each cell voltage via flying-capacitor sampling against a highly accurate internal reference. It drives high-side P-channel FETs through CHG and DCHG outputs while using an N-channel level shifter (Q3) for charge-FET gate control.
Its two-tier overcurrent architecture uses CDLY1 and CDLY2 pins to set user-programmable blanking delays: first-tier trips at 150 mV (6 A with 0.025 Ω sense resistor), second-tier at 375 mV (15 A), with hiccup-mode recovery and smart discharge activation above 15 mV BATLO drop during overcharge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Overvoltage Threshold | 4.20–4.30 V (UCC3957M-2 variant); enables precise cell-level charge cutoff without premature termination |
| Undervoltage Threshold | 2.5–2.7 V; triggers sleep mode and disables discharge to prevent lithium plating |
| Sleep Current | 3.5 µA typical; extends shelf life and enables low-power wake-on-charge detection |
| Supply Range | 6.5–20 V VDD; supports full 3S–4S Li-ion stack voltage range including charger transients |
| Cell Count Config | CLCNT pin selects 3-cell (high) or 4-cell (low); no external resistors required |
| Smart Discharge Threshold | 4–25 mV on BATLO; re-enables charge-FET for discharge-only conduction during overcharge hysteresis |
| First-Tier Blanking Time | 30–70 ms (CDLY1 = 0.1 µF); allows capacitive load surge without nuisance trip |
Pinout & Package
UCC3957M-2 is housed in a 16-pin SSOP (DBQ) package with 0.65 mm pitch, RoHS-compliant green finish, and JEDEC MSL Level-2 moisture sensitivity rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (1) | Power input | Connects to top of Li-ion stack; supplies internal regulators and logic |
| CLCNT (2) | Configuration input | Low = 4-cell mode; high = 3-cell mode; internal pull-down ensures default 4S operation |
| WU (3) | Wake-up input | Detects charger presence by sensing voltage >50 mV above VDD; exits sleep mode |
| AN1–AN3 (4–6) | Cell voltage inputs | Tap points between cells; enable individual cell monitoring in stacked configuration |
| AN4 (7) | Reference node | Common connection point for bottom of stack, current-sense resistor, and bypass caps |
| BATLO (8) | Current sense input | Measures voltage drop across external shunt to detect discharge overcurrent |
| CHGEN (9) | Charge enable input | Must be pulled high to DVDD/AVDD to permit charging; weak internal pulldown holds off by default |
| CDLY1 (10) | First-tier delay output | Drives external capacitor to set blanking time before hiccup-mode initiation |
| DVDD (16) | Digital supply output | 7.3 V regulated output; requires 0.1 µF bypass cap to AN4 for stable logic operation |
| AVDD (15) | Analog supply output | 7.3 V regulated output; requires 0.1 µF bypass cap to AN4 for precision reference stability |
| CHG (12) | Charge control output | Drives N-channel level shifter to turn off P-channel charge FET during overvoltage |
| DCHG (13) | Discharge control output | Directly drives gate of P-channel discharge FET; high = block discharge |
| CDLY2 (14) | Second-tier delay output | Extends blanking time for higher-current faults; sets ultra-fast response to hard shorts |
Key Features
| Feature | Design Value |
|---|---|
| Two-tier overcurrent protection | Programmable first-tier (150 mV / 6 A) and second-tier (375 mV / 15 A) thresholds enable robust surge handling and short-circuit immunity |
| Smart discharge during overcharge | Re-enables charge-FET for discharge-only conduction when BATLO >15 mV, reducing body-diode loss from ~1 W to ~20 mW |
| Flying-capacitor cell monitoring | Eliminates need for isolated supplies or complex level-shifting circuitry across multi-cell stacks |
| Loss-of-sense wire detection | Internal current sources flag open AN1/AN2/AN3 connections as overvoltage, preventing unsafe charging |
| Low-power sleep mode | 3.5 µA consumption with automatic wake-on-charge detection via WU pin voltage rise |
Applications
| Power Tool Battery Packs | Medical Portable Monitors |
|---|---|
|
Use Scenario: 4S Li-ion packs powering cordless drills with high peak discharge currents and strict safety compliance. IC Role / Device Role / Timing Role: Primary cell-balancing-agnostic protector managing independent charge/discharge FETs and detecting overcurrent within 10 ms. Use Value: Two-tier overcurrent prevents nuisance tripping during motor startup surges while delivering sub-200 µs response to true shorts. |
Use Scenario: 3S medical battery packs in portable ECG or infusion pumps requiring long shelf life and fail-safe undervoltage shutdown. IC Role / Device Role / Timing Role: Low-quiescent protector entering 3.5 µA sleep mode upon cell undervoltage and waking only on valid charger detection. Use Value: Sleep current minimizes self-discharge during storage; smart discharge preserves runtime during overcharge recovery. |
| Electric Scooter Battery Modules | Industrial Handheld Scanners |
|
Use Scenario: 4S battery modules in shared mobility scooters exposed to vibration-induced cell-sense disconnection. IC Role / Device Role / Timing Role: Open-wire detector using weak internal current sources to identify broken ANx connections and disable charging. Use Value: Prevents thermal runaway by halting charge when cell tap wires detach - a common field failure mode. |
Use Scenario: Compact 3S Li-ion packs in warehouse barcode scanners with tight PCB space and high reliability requirements. IC Role / Device Role / Timing Role: Single-chip protector replacing discrete solutions, integrating precision voltage references and hiccup-mode recovery. Use Value: SSOP-16 footprint reduces board area vs. multi-IC alternatives; 4.25 V overvoltage threshold matches common 3S Li-ion chemistry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar lithium-ion battery pack protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ77PL900DR | Integrated 4S analog front-end with built-in FET drivers; supports daisy-chain communication; higher BOM cost | Requires microcontroller interface; suited for systems needing telemetry and firmware updates | Choose BQ77PL900DR if system-level communication and diagnostics are required; UCC3957M-2 remains optimal for standalone, cost-sensitive protection. |
| MP2617GJ-Z | Single-chip solution with integrated charge/discharge FETs; fixed 4.2 V overvoltage; no CLCNT configuration pin | Limited to 4S only; lacks smart discharge and programmable overcurrent tiers | Choose MP2617GJ-Z for simplified 4S designs where external FET control and hiccup tuning are unnecessary. |
Compared with BQ77PL900DR and MP2617GJ-Z, the UCC3957M-2 uniquely delivers configurable 3S/4S operation, dual-blanking overcurrent protection, and smart discharge - all in a minimal external-component, FET-driver-only architecture ideal for cost-constrained, high-reliability battery packs.
Availability
UCC3957M-2 is available at Aetrix Electronics and suitable for power tool battery packs, medical portable monitors, electric scooter modules, industrial handheld scanners, and other applications requiring stable component supply with long lifecycle support.
Supply support for UCC3957M-2 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 expertise in battery management ICs.
The UCC3957 family was designed specifically for high-reliability, discrete-FET-based lithium-ion pack protection - emphasizing low quiescent current, robust fault handling, and flexible cell-count configuration without microcontroller dependency.
FAQ
What is the overvoltage threshold for UCC3957M-2?
The UCC3957M-2 has a nominal overvoltage threshold of 4.25 V, with a specified range of 4.20 V to 4.30 V at 25°C. This value is factory-trimmed and applies to each monitored cell individually. The UCC3957M-2 variant is distinct from UCC3957M-1 (4.20 V), UCC3957M-3 (4.30 V), and UCC3957M-4 (4.35 V), enabling precise matching to specific Li-ion cell chemistry requirements.
How does UCC3957M-2 enter and exit sleep mode?
The UCC3957M-2 enters sleep mode automatically when any cell voltage drops below the undervoltage threshold (2.5–2.7 V), reducing supply current to 3.5 µA typical. It exits sleep mode only when the WU pin voltage rises more than 50 mV above VDD - a condition met when a charger is connected and the N-channel level shifter pulls WU high. This ensures reliable wake-up without false triggers from noise or leakage.
What is the purpose of the CLCNT pin on UCC3957M-2?
The CLCNT pin on UCC3957M-2 configures the device for either three-cell or four-cell operation: tying CLCNT to DVDD/AVDD selects 3S mode, while grounding it to AN4 selects 4S mode. An internal pull-down ensures default 4S operation if left unconnected. This eliminates external configuration resistors and allows single-PCB reuse across both configurations.
Does UCC3957M-2 support smart discharge, and how does it work?
Yes, UCC3957M-2 implements smart discharge: when a cell exceeds the overvoltage threshold and the charge FET is turned off, the IC monitors BATLO voltage. If the drop exceeds 15 mV (e.g., 0.6 A through a 0.025 Ω shunt), the CHG output re-enables the charge FET for discharge-only conduction - bypassing the high-loss body diode and cutting power dissipation by >95% compared to standard operation.
What package type and environmental rating does UCC3957M-2 use?
UCC3957M-2 is supplied in a 16-pin SSOP (DBQ) package with 0.65 mm lead pitch, green RoHS-compliant finish (no Sb/Br), and JEDEC MSL Level-2 rating (260°C peak reflow, 1-year floor life). Tape-and-reel packaging is available as UCC3957MTR-2 (2500 units/reel), and the device operates from –20°C to +70°C ambient temperature.
UCC3957M-2 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Battery Protection
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 3 ~ 4
- Fault Protection:
- Over Current, Over/Under Voltage
- Interface:
- -
- Operating Temperature:
- -20°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
UCC3957M-2 FAQ
1.How can I place an order for UCC3957M-2 through Aetrix?
Please submit a Request for Quotation (RFQ) for UCC3957M-2 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 UCC3957M-2 reliable?
The price and inventory of UCC3957M-2 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UCC3957M-2 is usually 5 days.
3.What payment methods are accepted for UCC3957M-2?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UCC3957M-2 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UCC3957M-2?
UCC3957M-2 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UCC3957M-2 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 UCC3957M-2?
For technical support, including UCC3957M-2 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UCC3957M-2 requirements.
6.How does Aetrix verify that UCC3957M-2 is sourced from the original manufacturer or authorized distributors?
All UCC3957M-2 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 UCC3957M-2 meets industry standards.
7.What is the process for return or replacement of UCC3957M-2?
All UCC3957M-2 units undergo pre-shipment inspection (PSI). If there is an issue with UCC3957M-2, 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 UCC3957M-2 part is unused and in its original packaging.
Return procedure for UCC3957M-2:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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