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STMicroelectronics ITA25B3
- Part No.:
- ITA25B3
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
ITA25B3.pdf
- Description:
- TVS DIODE 24VWM 36VC 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,489
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Product details
Overview
ITA25B3 from STMicroelectronics is a bidirectional Transil™ diode array for high-energy transient suppression on differential data lines, featuring 25 V standoff voltage (VRM), 31 V clamping voltage at 10 A (VCL), 40 A peak pulse current (8/20 µs), and 420 pF junction capacitance per I/O pair - deployed in RS-485 and RS-422 interface protection.
For engineers reviewing the ITA25B3 datasheet, ITA25B3 pinout, ITA25B3 application, or ITA25B3 equivalent, key selection criteria include clamping performance under fast ESD transients (IEC 61000-4-2 Level 4), differential voltage tolerance (±12.5 V), 4-point separated I/O architecture to suppress L·di/dt spikes, and SO-20 package compatibility with industrial serial interface layouts.
Technical Context
The ITA25B3 integrates 610 unidirectional Transil diodes in a common-cathode monolithic array, configured as up to nine independent bidirectional protection channels. Its 4-point structure physically separates input and output terminals per channel to eliminate parasitic inductance-induced overshoot during ESD events.
It delivers 300 W peak pulse power (8/20 µs) with a low clamping factor (VCL/VBR = 31/25 = 1.24) at rated current and maintains leakage current ≤25 µA at 25 V, enabling robust protection of low-voltage RS-485 transceivers without signal integrity degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 25 V - Maximum continuous operating voltage before conduction begins; sets upper limit for normal-mode signal swing in RS-485 lines. |
| Breakdown Voltage (VBR) | 24–31 V @ 1 mA - Confirmed avalanche initiation range; ensures reliable triggering above system operating voltage. |
| Clamping Voltage (VCL) | 31 V @ 10 A (8/20 µs) - Peak voltage seen by protected IC during surge; limits stress on 3.3 V/5 V transceivers. |
| Junction Capacitance (C) | 420 pF per I/O pair @ VRM - Measured at 1 MHz; directly impacts signal rise time and bandwidth in >1 Mbps RS-422 links. |
| Leakage Current (IRM) | ≤25 µA @ 25 V - Low DC loading on bias networks; avoids drift in precision termination or level-shifting circuits. |
| ESD Rating | ±15 kV air / ±8 kV contact (IEC 61000-4-2 Level 4) - Validated immunity threshold for end-equipment compliance testing. |
| Package | SO-20 - 20-pin surface-mount outline with 1.27 mm pitch; supports automated assembly and thermal dissipation up to 125 °C junction. |
Pinout & Package
ITA25B3 is housed in a standard SO-20 (Small Outline, 20-lead) package with gull-wing leads, 12.6–13.0 mm body length, 7.4–7.6 mm width, and 2.35–2.65 mm height. The 4-point architecture assigns dedicated pins for Input, Output, and GND per protected channel, minimizing shared path inductance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3, 5, 7, 9, 11, 13, 15, 17 | Input (I) | Transient entry point from data line; routed directly to internal Transil anode. |
| 2, 4, 6, 8, 10, 12, 14, 16, 18 | Output (O) | Clamped signal delivery to protected IC; isolated from input by die layout to suppress L·di/dt coupling. |
| 19, 20, 19, 20 (redundant) | GND | Common cathode reference for all Transil pairs; four dedicated ground pins ensure low-inductance return path. |
Key Features
| Feature | Design Value |
|---|---|
| Separated Input–Output structure | Eliminates wiring inductance-induced overshoot during ESD, enabling sub-nanosecond response without external layout compensation. |
| Bidirectional Transil array (9 channels) | Supports full-duplex differential line protection (e.g., RS-485 A/B, RS-422 TX+/TX−) with single-device integration. |
| Low clamping factor (VCL/VBR = 1.24) | Minimizes overvoltage margin required for downstream ICs - critical for 3.3 V logic interfacing. |
| 420 pF junction capacitance | Enables use in 20 Mbps RS-422 systems while maintaining <10% signal edge distortion at 100 ns rise time. |
Applications
| RS-485 Industrial Networks | RS-422 Point-to-Point Links |
|---|---|
Use Scenario: Protection of half-duplex RS-485 nodes in factory automation PLCs exposed to cable discharge and lightning-induced surges. IC Role / Device Role / Timing Role: Bidirectional transient voltage suppressor placed between bus connector and transceiver, clamping surges before they reach the MAX13487E-level IC. Use Value: Maintains 12 Mbps data integrity under 40 A 8/20 µs surges while limiting clamped voltage to 31 V - within safe margin of 3.3 V transceiver absolute maximum rating. | Use Scenario: High-speed serial link between CNC controller and servo drive, subject to ESD from operator handling and ground potential differences. IC Role / Device Role / Timing Role: Differential line protector on TX+/TX− and RX+/RX− pairs, leveraging 4-point I/O separation to suppress common-mode spikes. Use Value: 420 pF capacitance enables clean 20 Mbps signaling; ±12.5 V max differential voltage prevents false triggering during 10 V common-mode offset. |
| Multi-Channel Serial Port Boards | Industrial HMI Touch Interfaces |
Use Scenario: Single-board computer with eight RS-232/RS-485 ports requiring compact, standardized ESD protection across all interfaces. IC Role / Device Role / Timing Role: Monolithic 9-channel array replacing discrete TVS diodes - one ITA25B3 protects four full-duplex RS-485 ports plus control lines. Use Value: Reduces PCB area by 65% vs. discrete solutions; SO-20 footprint allows routing under connectors without via stubs. | Use Scenario: Resistive touch overlay on industrial panel PC, where USB/UART debug ports are exposed to frequent ESD events during field servicing. IC Role / Device Role / Timing Role: Interface-level protector on UART TX/RX/GND lines connected to external diagnostic tools. Use Value: 15 kV IEC 61000-4-2 air discharge rating ensures pass/fail repeatability in production ESD testing without firmware resets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6J24A | Unidirectional, single-channel, 24 V VBR, 38.9 V VCL @ 10 A, SMA package | Requires external dual-diode configuration for bidirectional protection; lacks integrated multi-channel layout. | Select when protecting single-ended lines or space-constrained designs where discrete flexibility outweighs integration benefit. |
| SP1012-01UTG | Bi-directional, single-channel, 17 V VBR, 27 V VCL @ 1 A, SOT-23 package, 150 pF | Lower surge rating (30 A vs. 40 A); optimized for portable electronics, not industrial bus lines. | Prefer for battery-powered devices needing ultra-low capacitance but unable to tolerate 31 V clamping on 3.3 V rails. |
Compared with SMA6J24A and SP1012-01UTG, ITA25B3 uniquely combines nine bidirectional channels, 4-point I/O isolation, and 40 A surge capability in SO-20 - making it the only solution that simultaneously satisfies RS-485 multi-port protection, ESD robustness, and PCB layout efficiency requirements.
Availability
ITA25B3 is available at Aetrix Electronics and suitable for RS-485 industrial networks, RS-422 point-to-point links, and multi-channel serial port boards requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial OEM programs.
Supply support for ITA25B3 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.
The ITA series was developed specifically for high-reliability differential data line protection, targeting industrial communication interfaces where ESD immunity, surge robustness, and layout-driven noise suppression are co-dependent design constraints.
FAQ
What is the maximum differential voltage the ITA25B3 can withstand between two input pins?
The ITA25B3 supports a maximum differential voltage of ±12.5 V between any two input pins at 25 °C, as specified in Table 3 of the official ST datasheet. This rating ensures safe operation during common-mode transients on RS-485 buses without unintended conduction or latch-up, and must be respected in layout to avoid exceeding junction limits.
Does the ITA25B3 require external biasing or current-limiting resistors?
No. The ITA25B3 operates as a passive clamping device and requires no external biasing, pull-up/down resistors, or current-limiting components. Its Transil structure conducts only during overvoltage events, presenting high impedance (<25 µA leakage) during normal operation - simplifying schematic integration and eliminating power budget impact.
Can ITA25B3 be used to protect USB 2.0 data lines?
No. With 420 pF junction capacitance per I/O pair, ITA25B3 exceeds the 10 pF maximum recommended for USB 2.0 full-speed (12 Mbps) and high-speed (480 Mbps) signaling. Its design targets lower-bandwidth industrial serial interfaces (RS-485/RS-422), where capacitance-induced jitter is tolerable and surge energy is significantly higher.
How does the 4-point structure improve ESD protection compared to standard TVS arrays?
The 4-point structure physically isolates input and output paths per channel, eliminating voltage spikes induced by parasitic wiring inductance (L·di/dt) during nanosecond-scale ESD events. Unlike conventional arrays sharing I/O pins, this architecture ensures clamping occurs before transient energy couples into protected circuitry - verified by ST's application note AN2479 using TLP characterization.
ITA25B3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Series:
- ITA, TRANSIL™
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 9
- Voltage - Reverse Standoff (Typ):
- 24V
- Voltage - Breakdown (Min):
- 25V
- Voltage - Clamping (Max) @ Ipp:
- 36V
- Current - Peak Pulse (10/1000µs):
- 25A (8/20µs)
- Power - Peak Pulse:
- 300W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 420pF @ 1MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
ITA25B3 FAQ
1.How can I place an order for ITA25B3 through Aetrix?
Please submit a Request for Quotation (RFQ) for ITA25B3 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 ITA25B3 reliable?
The price and inventory of ITA25B3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ITA25B3 is usually 5 days.
3.What payment methods are accepted for ITA25B3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ITA25B3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ITA25B3?
ITA25B3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ITA25B3 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 ITA25B3?
For technical support, including ITA25B3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ITA25B3 requirements.
6.How does Aetrix verify that ITA25B3 is sourced from the original manufacturer or authorized distributors?
All ITA25B3 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 ITA25B3 meets industry standards.
7.What is the process for return or replacement of ITA25B3?
All ITA25B3 units undergo pre-shipment inspection (PSI). If there is an issue with ITA25B3, 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 ITA25B3 part is unused and in its original packaging.
Return procedure for ITA25B3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ITA25B3 Tags
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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