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Texas Instruments TL-SCSI285PWRE4
- Part No.:
- TL-SCSI285PWRE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
TL-SCSI285PWRE4.pdf
- Description:
- IC REG LIN 2.85V 500MA 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,843
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Product details
Overview
TL-SCSI285PWRE4 from Texas Instruments is a fixed-output, low-dropout linear regulator engineered exclusively for SCSI Alternative 2 active termination, delivering a tightly regulated 2.85 V ±1% (at TJ = 25°C), supporting up to 500 mA output current in the TSSOP-20 (PW) package, with 0.7 V maximum dropout at 500 mA and integrated thermal/overcurrent/overvoltage protection.
For engineers reviewing the TL-SCSI285PWRE4 datasheet, TL-SCSI285PWRE4 pinout, TL-SCSI285PWRE4 application, or TL-SCSI285PWRE4 equivalent, key selection considerations include its SCSI-specific 2.85-V output compliance, 20-pin TSSOP thermal performance (θJA = 83°C/W), active termination power efficiency versus passive resistor networks, and compatibility with 110-Ω line impedance matching.
Technical Context
The TL-SCSI285PWRE4 implements a monolithic LDO architecture optimized for stable DC biasing of SCSI termination networks under dynamic bus loading. Its internal reference and error amplifier maintain output regulation across input voltages from 3.55 V to 5.5 V and junction temperatures from 0°C to 125°C.
Designed for direct integration into SCSI backplanes and host adapters, it replaces discrete resistor-based termination by sourcing precise current through series-connected 110-Ω resistors, eliminating signal reflections while reducing continuous power draw versus passive schemes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.85 V ±1% at TJ = 25°C; ensures tight line-driver current tolerance per SCSI Alternative 2 spec, increasing noise margin. |
| Dropout Voltage | 0.7 V max at 500 mA; enables operation with low TERMPWR headroom, improving isolation in battery-powered or margin-constrained systems. |
| Output Current | 500 mA max (PW package); supports full 8-bit SCSI bus termination (18 asserted lines) with 26–49 mA bias current. |
| Input Voltage Range | 3.55 V to 5.5 V; compatible with standard 5-V logic supplies while tolerating brownout conditions down to 3.55 V. |
| Thermal Protection | Internal thermal-overload shutdown; prevents damage during sustained overload or poor PCB heatsinking in TSSOP-20 package. |
| Ripple Rejection | –62 dB at 120 Hz; suppresses supply ripple from noisy switching regulators or shared rail sources feeding SCSI subsystems. |
| Output Noise | 500 µV RMS (10 Hz–100 kHz); minimizes induced jitter on SCSI differential signaling paths. |
Pinout & Package
TSSOP-20 (PW) package with exposed thermal pad; 8.0 mm × 6.95 mm footprint; moisture sensitivity level 1 (260°C reflow compatible); RoHS-compliant, green (no Sb/Br) finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3, 4, 6, 7, 9, 10, 12, 13, 15, 16, 18, 19, 20 | GND | Multiple ground terminals tied internally; must be connected to low-impedance system ground plane for thermal dissipation and noise control. |
| 2 | INPUT | Main unregulated input (3.55–5.5 V); requires 0.1-µF ceramic bypass capacitor close to pin. |
| 5, 8, 11, 14, 17 | OUTPUT | Regulated 2.85-V output; drives 110-Ω termination resistors; requires 22-µF tantalum output capacitor with ≤1.5 Ω ESR. |
Key Features
| Feature | Design Value |
|---|---|
| SCSI Alternative 2 Compliance | Fixed 2.85-V output meets ANSI X3.131-1994 termination voltage requirement without external trimming. |
| Low-Dropout Operation | 0.7-V dropout at 500 mA enables use with degraded TERMPWR rails, extending system uptime during supply sag. |
| Integrated Protection | Combines overcurrent limiting, thermal shutdown, and overvoltage clamp-eliminates need for discrete protection components. |
| ESD Robustness | Incorporates on-chip ESD protection per JEDEC JS-001; withstands ≥2 kV HBM, critical for hot-plug SCSI environments. |
| Stability Assurance | Validated with 22-µF tantalum output cap (ESR 1.5 Ω); supports stable operation across –40°C to +125°C junction range. |
Applications
| SCSI Host Adapter Termination | SCSI Peripheral Device Backplane |
|---|---|
|
Use Scenario: Integrated into motherboard-level SCSI host adapters to provide active termination for internal bus connections. IC Role / Device Role / Timing Role: Supplies regulated 2.85-V bias to parallel SCSI termination network, replacing 220-Ω/330-Ω passive resistor pairs. Use Value: Reduces continuous power consumption by >60% versus passive termination while maintaining signal integrity across 5-MB/s asynchronous transfers. |
Use Scenario: Mounted on SCSI peripheral device PCBs (e.g., tape drives, scanners) to enable self-terminating behavior when last in chain. IC Role / Device Role / Timing Role: Acts as programmable termination voltage source synchronized to bus activity via bias current scaling (3–62 mA). Use Value: Eliminates manual terminator jumper configuration; supports automatic detection of end-of-chain position via current-sense feedback. |
| Battery-Powered SCSI Docking Station | Industrial SCSI Data Acquisition Module |
|
Use Scenario: Used in portable SCSI docking stations where TERMPWR is derived from Li-ion battery (3.3–4.2 V range). IC Role / Device Role / Timing Role: Low-dropout regulator sustaining 2.85-V termination voltage despite battery discharge, enabling reliable hot-swap operation. Use Value: Maintains >30 dB noise margin at 4.0-V input (0.7-V dropout), preventing false ACK/REQ assertion during voltage droop. |
Use Scenario: Embedded in ruggedized data acquisition systems operating in extended temperature environments (–20°C to +70°C ambient). IC Role / Device Role / Timing Role: Provides thermally robust termination supply with internal thermal shutdown activating at TJ ≥ 150°C. Use Value: Ensures uninterrupted SCSI communication during prolonged high-load acquisition cycles without derating or forced airflow. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SCSI active termination applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL-SCSI285KCSE3 | TO-220-3 package; higher thermal mass (θJA = 22°C/W); 620-mA output rating; leaded, Pb-free finish. | Requires heatsink mounting; suited for high-power, fixed-installation SCSI controllers with ample board space. | Select when thermal budget exceeds TSSOP limits or legacy through-hole assembly is required. |
| TL-SCSI285PWRG4 | Identical TSSOP-20 (PW) package and electrical specs; green (RoHS & no Sb/Br) finish; same MSL-1 rating. | No functional difference; differs only in material composition compliance (Sb/Br content). | Choose TL-SCSI285PWRE4 for standard green compliance; TL-SCSI285PWRG4 if stricter halogen-free requirements apply. |
Compared with TL-SCSI285KCSE3, TL-SCSI285PWRE4 offers superior board-area efficiency and surface-mount compatibility but requires careful thermal layout due to higher θJA; versus TL-SCSI285PWRG4, it provides identical performance with equivalent environmental compliance for mainstream industrial use.
Availability
TL-SCSI285PWRE4 is available at Aetrix Electronics and suitable for SCSI host adapter design, industrial data acquisition modules, battery-powered docking stations, and ruggedized peripheral backplanes requiring stable component supply and long-term obsolescence management.
Supply support for TL-SCSI285PWRE4 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 company specializing in analog, embedded processing, and connectivity technologies, with over 90 years of innovation in power management and interface solutions.
The TL-SCSI285 product line was developed to replace passive SCSI termination networks with integrated, low-dropout regulators-enabling lower power, higher noise immunity, and simplified board layout in small computer systems interface implementations.
FAQ
What is the maximum output current supported by the TL-SCSI285PWRE4?
The TL-SCSI285PWRE4 supports up to 500 mA output current in the TSSOP-20 (PW) package, as specified in the recommended operating conditions. This rating accounts for thermal limitations of the PW package (θJA = 83°C/W); exceeding 500 mA risks thermal shutdown under typical PCB copper area assumptions. The TL-SCSI285PWRE4 datasheet confirms this limit applies across the full 0°C to 125°C junction temperature range.
Does the TL-SCSI285PWRE4 require external capacitors, and what values are recommended?
Yes, the TL-SCSI285PWRE4 requires both input and output capacitors for stability and transient response. A 0.1-µF ceramic capacitor must be placed adjacent to the INPUT pin, and a 22.0-µF tantalum capacitor with ≤1.5 Ω ESR is mandatory on the OUTPUT pins. These values are validated in the TL-SCSI285PWRE4 datasheet Figures 2 and 3 for stable operation across load currents up to 500 mA and temperatures from 0°C to 125°C.
How does the TL-SCSI285PWRE4 implement SCSI Alternative 2 active termination?
The TL-SCSI285PWRE4 implements SCSI Alternative 2 active termination by delivering a precise 2.85-V output that biases 110-Ω resistors connected between each SCSI signal line and ground. This matches the characteristic impedance of standard SCSI cables, eliminating reflections without the 220-Ω/330-Ω resistor pairs used in passive schemes. The TL-SCSI285PWRE4's ±1% output tolerance ensures consistent line-driver current, directly improving noise margin per ANSI X3.131-1994.
Is the TL-SCSI285PWRE4 pin-compatible with other variants like TL-SCSI285PWR or TL-SCSI285PWRG4?
Yes, the TL-SCSI285PWRE4 is pin-compatible with TL-SCSI285PWR and TL-SCSI285PWRG4-same TSSOP-20 (PW) package, identical pinout (2×10 grid), and identical electrical specifications. The differences are limited to material composition (E4 = green, RoHS & no Sb/Br; G4 = same compliance; base PWR = unspecified finish) and packaging tape/reel markings. No PCB layout changes are needed when substituting among these variants.
What protection features are built into the TL-SCSI285PWRE4?
The TL-SCSI285PWRE4 integrates three critical protection functions: internal overcurrent-limiting circuitry that folds back output current during short-circuit events; thermal-overload protection that disables output when junction temperature exceeds safe limits; and overvoltage protection that clamps input transients above 7.5 V. These features are documented in the absolute maximum ratings and electrical characteristics tables of the TL-SCSI285PWRE4 datasheet and require no external components to function.
TL-SCSI285PWRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.85V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.8V @ 620mA
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- -
- Current - Supply (Max):
- -
- PSRR:
- 62dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Over Voltage
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
TL-SCSI285PWRE4 FAQ
1.How can I place an order for TL-SCSI285PWRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TL-SCSI285PWRE4 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 TL-SCSI285PWRE4 reliable?
The price and inventory of TL-SCSI285PWRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL-SCSI285PWRE4 is usually 5 days.
3.What payment methods are accepted for TL-SCSI285PWRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL-SCSI285PWRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL-SCSI285PWRE4?
TL-SCSI285PWRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL-SCSI285PWRE4 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 TL-SCSI285PWRE4?
For technical support, including TL-SCSI285PWRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL-SCSI285PWRE4 requirements.
6.How does Aetrix verify that TL-SCSI285PWRE4 is sourced from the original manufacturer or authorized distributors?
All TL-SCSI285PWRE4 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 TL-SCSI285PWRE4 meets industry standards.
7.What is the process for return or replacement of TL-SCSI285PWRE4?
All TL-SCSI285PWRE4 units undergo pre-shipment inspection (PSI). If there is an issue with TL-SCSI285PWRE4, 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 TL-SCSI285PWRE4 part is unused and in its original packaging.
Return procedure for TL-SCSI285PWRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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