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Texas Instruments TPS2377DR-1G4
- Part No.:
- TPS2377DR-1G4
- Manufacturer:
- Texas Instruments
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
TPS2377DR-1G4.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,670
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Product details
Overview
TPS2377DR-1G4 from Texas Instruments is an IEEE 802.3af-compliant Powered Device (PD) controller IC for PoE applications, integrating a 0.58-Ω 100-V low-side MOSFET switch, fixed legacy UVLO thresholds (30.5 V turn-on / 35.1 V turn-off), 450-mA operational current limit, and programmable inrush current control via external ILIM resistor. It operates across –40°C to 85°C and supports VoIP phones, WLAN access points, and security cameras.
For engineers reviewing the TPS2377DR-1G4 datasheet, TPS2377DR-1G4 pinout, TPS2377DR-1G4 application, or TPS2377DR-1G4 equivalent, key selection considerations include its legacy UVLO behavior, open-drain PG reporting, 8-pin SOIC package compatibility, and classification resistor–based power class assignment per IEEE 802.3af Class 0–4.
Technical Context
The TPS2377DR-1G4 implements detection, classification, and undervoltage lockout using dedicated comparators with hysteresis-specifically configured for legacy PoE systems with lower input voltage margins. Its DET pin enables 24.9-kΩ detection signature generation, while CLASS pin supports classification currents from 2.2 mA to 41.2 mA depending on external resistor value (255 Ω to 4420 Ω).
It features a true open-drain PG output referenced to RTN, thermal shutdown at 135°C with 20°C hysteresis, and internal pass device with 0.58-Ω typical rDS(on). The UVLO thresholds are fixed (30.5 V rising / 35.1 V falling), differing from TPS2375's 802.3af-compliant thresholds and TPS2376's adjustable UVLO architecture.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UVLO Turn-On Threshold | 30.5 V (rising); enables PD power-up when PSE voltage exceeds this level, optimized for legacy PoE systems with marginal input voltage |
| UVLO Turn-Off Threshold | 35.1 V (falling); maintains operation until input drops below this point, providing 4.5 V hysteresis to prevent oscillation during cable voltage sag |
| Operational Current Limit | 450 mA (typical); clamps RTN current during normal operation to comply with IEEE 802.3af PSE current monitoring requirements |
| Inrush Current Control | Programmable via ILIM pin (62.5–500 kΩ); sets startup surge limit to prevent PSE dropout during bulk capacitor charging |
| Pass Device rDS(on) | 0.58 Ω (typical at 300 mA); minimizes conduction loss and self-heating in low-side switching path for DC/DC converter input |
| Power-Good Output | Open-drain PG referenced to RTN; asserts high-impedance state only after successful classification and stable RTN voltage >9.5 V |
| Operating Temperature | –40°C to +85°C; validated for industrial-grade deployment in uncontrolled ambient environments such as outdoor AP enclosures |
Pinout & Package
TPS2377DR-1G4 is housed in an 8-pin SOIC (D) package with exposed pad for thermal enhancement. Pin numbering follows standard SOIC top-view orientation (pin 1 at top-left corner, counterclockwise).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Inrush current programming input | Connects to VSS via resistor (178 kΩ typical) to set startup surge limit; open or shorted condition disables inrush control |
| CLASS (Pin 2) | Classification current source | Sinks current through external resistor (e.g., 357 Ω for Class 3) during 13–21 V window to signal PD power class to PSE |
| DET (Pin 3) | Detection signature generator | Pulls R(DET)=24.9 kΩ to VSS during 1.4–11.3 V range to present 25-kΩ incremental resistance to PSE |
| VSS (Pin 4) | Input return reference | Local ground for controller bias circuits; connects to negative side of input diode bridge before RTN switching node |
| RTN (Pin 5) | Switched load return | Low-side output terminal feeding downstream DC/DC converter; carries full load current up to 450 mA |
| PG (Pin 6) | Power-good status indicator | Open-drain output pulled to RTN internally; requires external pullup to VDD or logic rail for active-high signaling |
| N/C (Pin 7) | No connection | Unbonded pin; must remain floating-no routing or PCB trace allowed |
| VDD (Pin 8) | Positive input supply | Connects directly to rectified PSE output; supplies controller bias and serves as voltage monitoring point for UVLO and classification |
Key Features
| Feature | Design Value |
|---|---|
| Legacy UVLO thresholds | 30.5 V turn-on / 35.1 V turn-off enables reliable startup with older PSEs delivering <44 V nominal output |
| Integrated 100-V low-side switch | 0.58-Ω rDS(on) reduces conduction loss and eliminates need for external MOSFET in PoE front-end designs |
| Programmable inrush limiting | External ILIM resistor allows precise control of startup surge to match bulk capacitance and avoid PSE current-limit tripping |
| IEEE 802.3af compliance | Fully implements detection (25-kΩ signature), classification (Class 0–4), and maintain-power-signature (MPS) timing per standard |
| 15-kV system-level ESD protection | Withstands contact/air discharge per EN61000-4-2 at RJ-45 interface without external TVS, simplifying front-end BOM |
Applications
| VoIP Phones | WLAN Access Points |
|---|---|
Use Scenario: Power delivery over existing Cat5e Ethernet cabling to desk-mounted IP handsets with integrated audio codec and Ethernet PHY. IC Role / Device Role / Timing Role: TPS2377DR-1G4 acts as primary PD controller, managing detection/classification handshake, enabling 48-V-to-3.3/5-V DC/DC conversion, and asserting PG to release processor reset. Use Value: Enables single-cable deployment without local AC adapter; legacy UVLO ensures compatibility with installed base of Cisco Catalyst switches pre-dating 802.3at. | Use Scenario: Indoor/outdoor wireless infrastructure requiring PoE-powered 2.4/5 GHz radios, MAC processors, and antenna amplifiers. IC Role / Device Role / Timing Role: TPS2377DR-1G4 controls power sequencing to RF front-end and baseband SoC, monitors RTN current for fault detection, and signals stable rail via PG to enable Wi-Fi firmware boot. Use Value: Programmable inrush prevents brownout during capacitor charging across long cable runs; 100-V rating accommodates worst-case PSE overshoot in noisy electrical environments. |
| Security Cameras | POS Terminals |
Use Scenario: Outdoor PTZ cameras with motorized pan/tilt, IR illumination, and video streaming over Ethernet. IC Role / Device Role / Timing Role: TPS2377DR-1G4 provides isolated power switching, thermal shutdown protection during extended IR operation, and PG-driven enable for image sensor and encoder subsystems. Use Value: Fixed 450-mA current limit ensures PSE stays within safe operating area during motor stall events; SOIC package supports cost-effective reflow assembly. | Use Scenario: Retail point-of-sale terminals integrating barcode scanners, receipt printers, and touch displays powered via PoE. IC Role / Device Role / Timing Role: TPS2377DR-1G4 manages multi-rail power delivery (5 V for USB peripherals, 12 V for printer head), coordinates classification for Class 4 (255 Ω) to secure full 12.95 W at PD input. Use Value: CLASS pin resistor selection directly maps to IEEE-defined power classes, eliminating software configuration and ensuring interoperability with Aruba and HPE PSEs. |
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 | Fixed 802.3af-compliant UVLO (39.3 V turn-on / 30.5 V turn-off); higher hysteresis; identical pinout and feature set otherwise | Designed for new deployments with IEEE-compliant PSEs; unsuitable for legacy systems with slow-rising or low-voltage PSE outputs | Select TPS2375D when designing for modern switches (e.g., Cisco IE-3000, Juniper EX2200) requiring strict 802.3af adherence |
| TPS2376D | Adjustable UVLO via external resistor divider on UVLO pin; adds pin 7 functionality not present on TPS2377DR-1G4 | Supports custom UVLO thresholds for hybrid or proprietary PoE implementations; requires additional PCB routing and component | Choose TPS2376D only when UVLO tuning is mandatory-e.g., integration with non-standard midspan injectors or battery-backed PSEs |
Compared with TPS2377DR-1G4, TPS2375D offers stricter 802.3af compliance but risks startup failure on aging infrastructure, while TPS2376D adds design flexibility at the cost of layout complexity and BOM increase-TPS2377DR-1G4 remains optimal for field-replacement and brownfield PoE upgrades.
Availability
TPS2377DR-1G4 is available at Aetrix Electronics and suitable for VoIP phone manufacturing, WLAN access point production, and security camera OEM programs requiring stable component supply with guaranteed long-term availability.
Supply support for TPS2377DR-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 solutions, with decades of leadership in power management and industrial interface ICs.
The TPS237x family was designed specifically for IEEE 802.3af Powered Device control, targeting cost-sensitive, space-constrained PoE endpoints requiring integrated detection, classification, and power-switching functionality.
FAQ
What is the UVLO behavior of the TPS2377DR-1G4 compared to other TPS237x variants?
The TPS2377DR-1G4 uses fixed legacy UVLO thresholds-30.5 V turn-on and 35.1 V turn-off-with 4.5 V hysteresis. This differs from TPS2375D's 802.3af-compliant thresholds (39.3 V / 30.5 V) and TPS2376D's adjustable UVLO. The TPS2377DR-1G4 UVLO is optimized for compatibility with older PSEs that deliver lower or slower-rising input voltages, making it ideal for brownfield deployments where PSE voltage margin is constrained.
How does the TPS2377DR-1G4 implement IEEE 802.3af detection and classification?
The TPS2377DR-1G4 implements detection by pulling the DET pin low through an external 24.9-kΩ resistor to generate a 25-kΩ incremental resistance signature between 1.4 V and 11.3 V. For classification, it sources current from the CLASS pin through a precision resistor (e.g., 357 Ω for Class 3) when VDD is between 13 V and 21 V. The resulting current (27.1–41.2 mA) identifies the PD's power class to the PSE. Both functions are fully autonomous and require no microcontroller intervention.
Can the TPS2377DR-1G4 be used in Class 4 PoE applications?
Yes, the TPS2377DR-1G4 supports Class 4 operation using a 255-Ω classification resistor, which draws 38.0–41.2 mA during classification-within the IEEE 802.3af Class 4 specification (36–44 mA). Its 450-mA operational current limit and 100-V pass device rating ensure safe delivery of up to 12.95 W at the PD input, matching the maximum power budget defined for Class 4 under the standard.
What is the purpose of the N/C pin on the TPS2377DR-1G4?
Pin 7 on the TPS2377DR-1G4 is designated N/C (No Connection) and is internally unbonded. It must remain unconnected-no PCB trace, solder mask opening, or component attachment is permitted. Unlike the TPS2376D, which uses Pin 7 for UVLO resistor-divider input, the TPS2377DR-1G4 has no internal connection to this pin, and routing to it may cause parasitic coupling or ESD susceptibility.
Does the TPS2377DR-1G4 require an external pull-up resistor on the PG pin?
Yes, the PG pin on the TPS2377DR-1G4 is an open-drain output referenced to RTN and requires an external pull-up resistor (typically 10 kΩ to VDD or system logic rail) to generate a valid active-high power-good signal. Without this pull-up, PG remains floating during normal operation and cannot reliably drive microcontroller reset release or DC/DC enable logic. The internal pull-down only activates during fault or pre-classification states.
TPS2377DR-1G4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
TPS2377DR-1G4 FAQ
1.How can I place an order for TPS2377DR-1G4 through Aetrix?
Please submit a Request for Quotation (RFQ) for TPS2377DR-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 TPS2377DR-1G4 reliable?
The price and inventory of TPS2377DR-1G4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TPS2377DR-1G4 is usually 5 days.
3.What payment methods are accepted for TPS2377DR-1G4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TPS2377DR-1G4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TPS2377DR-1G4?
TPS2377DR-1G4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TPS2377DR-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 TPS2377DR-1G4?
For technical support, including TPS2377DR-1G4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TPS2377DR-1G4 requirements.
6.How does Aetrix verify that TPS2377DR-1G4 is sourced from the original manufacturer or authorized distributors?
All TPS2377DR-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 TPS2377DR-1G4 meets industry standards.
7.What is the process for return or replacement of TPS2377DR-1G4?
All TPS2377DR-1G4 units undergo pre-shipment inspection (PSI). If there is an issue with TPS2377DR-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 TPS2377DR-1G4 part is unused and in its original packaging.
Return procedure for TPS2377DR-1G4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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