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Texas Instruments TPS2377D-1G4
- Part No.:
- TPS2377D-1G4
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TPS2377D-1G4.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,252
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Product details
Overview
TPS2377D-1G4 from Texas Instruments is an IEEE 802.3af-compliant Powered Device (PD) controller IC for Power over Ethernet applications, integrating a 0.58-Ω 100-V low-side MOSFET switch, programmable inrush current control (via ILIM pin), fixed 450-mA operational current limit, and legacy-mode UVLO thresholds (35.1 V rising / 30.5 V falling). It operates across –40°C to 85°C and supports Class 3 PD implementations in VoIP phones and security cameras.
For engineers reviewing the TPS2377D-1G4 datasheet, TPS2377D-1G4 pinout, TPS2377D-1G4 application, or TPS2377D-1G4 equivalent, key selection considerations include its legacy UVLO behavior, SOIC-8 package compatibility, RTN-sinking current limit accuracy, and open-drain PG reporting with 75–225 µs deglitch timing - all critical for interoperability with non-compliant PSEs.
Technical Context
The TPS2377D-1G4 implements detection via 24.9-kΩ DET-to-VDD resistor, classification using external CLASS-to-VSS resistors (e.g., 357 Ω for Class 3), and UVLO monitoring with fixed thresholds optimized for legacy PoE systems. Its internal comparator hysteresis ensures stable state transitions between detection (VDD < 11.3 V), classification (13–21 V), and powered operation (>21 V).
It features a true open-drain PG output referenced to RTN, not VSS, and uses RTN as both switched return path and current-sense reference for inrush and operational limiting. The ILIM pin accepts 62.5–500 kΩ resistors to set inrush current from 100 mA to 180 mA, while the pass device delivers ≤0.58 Ω rDS(on) at 300 mA with thermal shutdown at 135°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Rising Threshold | 35.1 V nominal - enables power-up only after legacy PSE reaches sufficient voltage, avoiding false starts on slow-rising supplies |
| UVLO Falling Threshold | 30.5 V nominal - maintains operation through cable voltage sag up to 4.6 V drop, supporting older midspans |
| Operational Current Limit | 450 mA typical - enforces IEEE 802.3af Class 3 compliance (≤12.95 W at PD input) with ±5% tolerance |
| Inrush Current Limit | 130 mA typical (with 178 kΩ ILIM resistor) - prevents line collapse during bulk capacitor charging without requiring external FET |
| rDS(on) | 0.58 Ω max at 300 mA - minimizes conduction loss and self-heating in continuous 12-W load scenarios |
| PG Output Type | Open-drain referenced to RTN - allows flexible pull-up to VDD or auxiliary rail; requires external resistor for logic-level assertion |
| ESD Rating | 15-kV system-level contact/air per EN61000-4-2 - protects against RJ-45 port ESD events without external TVS |
Pinout & Package
TPS2377D-1G4 is housed in an 8-pin SOIC (D−8) package with exposed pad thermal enhancement, compliant with JEDEC MS-012AC and RoHS requirements. Pin 1 is ILIM; pin 4 is VSS (input ground); pin 5 is RTN (switched return); pin 6 is PG (open-drain power-good); pin 8 is VDD (PoE input rail).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Inrush current programming input | Accepts resistor to VSS to set startup inrush limit (100–180 mA range); must not be left floating or shorted |
| CLASS (Pin 2) | Classification current source | Sinks precise current (e.g., 28.0 mA @ 357 Ω) during 13–21 V window to signal Class 3 power requirement to PSE |
| DET (Pin 3) | Detection signature generator | Pulls VDD-to-VSS path via external 24.9-kΩ resistor to present 25-kΩ incremental resistance to PSE during detection |
| VSS (Pin 4) | Input supply return | Reference node for DET, CLASS, ILIM, and UVLO circuitry; isolated from RTN to prevent ground loop in diode-bridge front-end |
| RTN (Pin 5) | Switched load return | Carries full load current (≤450 mA); serves as current-sense node for limit amps and PG comparator reference |
| PG (Pin 6) | Power-good status output | Open-drain output pulled to RTN when in fault/inrush; high-Z when enabled and stable - requires external pull-up |
| N/C (Pin 7) | No connection | Unbonded; must remain unconnected - differs from TPS2376's UVLO pin which is not internally connected here |
| VDD (Pin 8) | PoE input rail | Accepts 0–57 V DC from rectified PSE; powers internal circuitry and feeds downstream DC/DC converter input |
Key Features
| Feature | Design Value |
|---|---|
| Legacy UVLO thresholds | 35.1 V rise / 30.5 V fall - enables reliable startup with pre-2003 PoE midspans and non-compliant switches lacking 44-V minimum output |
| Integrated 100-V low-side switch | 0.58-Ω rDS(on) - eliminates need for external MOSFET in Class 3 designs, reducing BOM count and layout area |
| Programmable inrush control | 100–180 mA range via ILIM resistor - accommodates large hold-up capacitors while preventing PSE current-limit tripping |
| True open-drain PG referenced to RTN | 75–225 µs deglitch - avoids false power-loss assertions during transient load steps or cable impedance mismatches |
| 15-kV system-level ESD protection | EN61000-4-2 certified - withstands repeated RJ-45 hot-plug events without external protection components |
Applications
| VoIP Phones | WLAN Access Points |
|---|---|
Use Scenario: Powered via Category 5e cabling from legacy PoE switch with 38-V output capability. IC Role / Device Role / Timing Role: PD controller managing detection, classification (Class 3), and regulated 12-V DC/DC input under variable cable drop. Use Value: Legacy UVLO ensures consistent power-up even when PSE output rises slowly from 32 V to 38 V, avoiding brownout resets. |
Use Scenario: Dual-band 802.11ac AP deployed in ceiling-mounted enclosures with limited airflow. IC Role / Device Role / Timing Role: Provides inrush-limited 12.95-W power delivery and thermal shutdown coordination with baseband SoC. Use Value: 0.58-Ω rDS(on) limits junction temperature rise to <15°C above ambient at full load, eliminating need for heatsink. |
| Security Cameras | POS Terminals |
Use Scenario: Outdoor IP camera with IR illumination requiring stable 12-V/1-A rail from midspan injector. IC Role / Device Role / Timing Role: Controls power sequencing, monitors MPS continuity, and asserts PG only after RTN stabilizes post-inrush. Use Value: PG deglitch (75–225 µs) prevents false disconnect signals during IR LED turn-on transients drawing 300-mA spikes. |
Use Scenario: Retail point-of-sale terminal with barcode scanner, display, and EMV reader powered over single Ethernet cable. IC Role / Device Role / Timing Role: Serves as primary PD interface, enabling simultaneous operation of multiple peripherals within 12.95-W budget. Use Value: Fixed 450-mA current limit guarantees PSE compliance without software calibration, simplifying UL/CE certification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Powered Device controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS2375D-1G4 | IEEE 802.3af-compliant UVLO (39.3 V rise / 30.5 V fall); higher hysteresis (8.8 V) | Better suited for new deployments with compliant PSEs; may misbehave with legacy midspans exhibiting slow voltage ramp | Select TPS2375D-1G4 when designing for certified 802.3af infrastructure and requiring maximum hysteresis margin. |
| TPS2376D-1G4 | Adjustable UVLO via external resistor divider on UVLO pin; otherwise functionally identical | Enables fine-tuning for hybrid PSE environments but adds two passive components and layout complexity | Choose TPS2376D-1G4 only when field validation shows inconsistent startup across mixed PSE fleets and adjustable thresholds are mandatory. |
Compared with TPS2375D-1G4 and TPS2376D-1G4, the TPS2377D-1G4 offers deterministic legacy-system compatibility without external components or configuration overhead - making it optimal for cost-sensitive, high-volume deployments where PSE vintage is known and fixed.
Availability
TPS2377D-1G4 is available at Aetrix Electronics and suitable for VoIP phones, security cameras, WLAN access points, and POS terminals requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for TPS2377D-1G4 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 connectivity technologies, with decades of leadership in Power over Ethernet solutions.
The TPS237x family was designed specifically for IEEE 802.3af Powered Device control, targeting cost-effective, integrated PoE endpoint implementations in voice, video, and data infrastructure equipment.
FAQ
What is the UVLO behavior of the TPS2377D-1G4 compared to other members of the TPS237x family?
The TPS2377D-1G4 features fixed legacy UVLO thresholds of 35.1 V (rising) and 30.5 V (falling), optimized for interoperability with pre-2003 PoE midspans and non-compliant switches. Unlike the TPS2375D-1G4 (39.3 V / 30.5 V) or TPS2376D-1G4 (adjustable), the TPS2377D-1G4 provides deterministic startup in environments where PSE output voltage may not reach 44 V. This makes TPS2377D-1G4 ideal for brownfield deployments.
How does the TPS2377D-1G4 implement inrush current limiting, and what resistor value sets 130 mA?
The TPS2377D-1G4 uses an external resistor from ILIM (Pin 1) to VSS to program inrush current. With a 178-kΩ ±1% resistor, the TPS2377D-1G4 delivers a typical inrush limit of 130 mA - verified across –40°C to 85°C. This value balances fast capacitor charging against PSE current-limit tripping in legacy systems. The TPS2377D-1G4 datasheet specifies R(ILIM) range as 62.5 kΩ to 500 kΩ for 100–180 mA adjustment.
Can the TPS2377D-1G4 be used in Class 4 or higher PoE applications?
No. The TPS2377D-1G4 is strictly IEEE 802.3af-compliant and rated for Class 0–4 detection/classification, but its 450-mA fixed current limit and 12.95-W maximum input power align only with Class 3 (6.49–12.95 W) and lower. It lacks the higher-current pass device, enhanced thermal design, and 802.3at/802.3bt signaling required for Type 2 (PoE+) or Type 3/4 (UPoE/HiPoE) applications. Use TPS2375-4 or TPS23881 for those standards.
What is the role of the N/C pin (Pin 7) on the TPS2377D-1G4, and can it be tied to ground?
Pin 7 on the TPS2377D-1G4 is explicitly designated as No Connection (N/C) - it is unbonded and internally unconnected. TI documentation confirms this pin must remain unconnected; tying it to ground, VDD, or any other node may cause unpredictable behavior or damage. This differs from the TPS2376D-1G4, where Pin 7 is the UVLO input - a functional distinction clearly documented in the TPS2377D-1G4 datasheet.
Does the TPS2377D-1G4 require an external pull-up resistor on the PG pin, and why?
Yes, the TPS2377D-1G4 PG pin is an open-drain output referenced to RTN, not VSS. It actively pulls down to RTN during fault or inrush states but presents high impedance when asserting "power good." An external pull-up resistor (typically 10 kΩ to VDD or auxiliary rail) is mandatory to generate a valid logic-high signal for host monitoring. Without it, PG remains undefined, risking incorrect system power sequencing or watchdog timeouts.
TPS2377D-1G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Type:
- Controller (PD)
- Number of Channels:
- 1
- Power - Max:
- 12.95 W
- Internal Switch(s):
- Yes
- Auxiliary Sense:
- No
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 0V ~ 57V
- Current - Supply:
- 240µA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
TPS2377D-1G4 FAQ
1.How can I place an order for TPS2377D-1G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS2377D-1G4 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 TPS2377D-1G4 reliable?
The price and inventory of TPS2377D-1G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS2377D-1G4 is usually 5 days.
3.What payment methods are accepted for TPS2377D-1G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS2377D-1G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS2377D-1G4?
TPS2377D-1G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS2377D-1G4 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 TPS2377D-1G4?
For technical support, including TPS2377D-1G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS2377D-1G4 requirements.
6.How does Aetrix verify that TPS2377D-1G4 is sourced from the original manufacturer or authorized distributors?
All TPS2377D-1G4 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 TPS2377D-1G4 meets industry standards.
7.What is the process for return or replacement of TPS2377D-1G4?
All TPS2377D-1G4 units undergo pre-shipment inspection (PSI). If there is an issue with TPS2377D-1G4, 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 TPS2377D-1G4 part is unused and in its original packaging.
Return procedure for TPS2377D-1G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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