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NXP Semiconductors MCZ34670EG
- Part No.:
- MCZ34670EG
- Manufacturer:
- NXP Semiconductors
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MCZ34670EG.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,985
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Product details
Overview
MCZ34670EG from Freescale Semiconductor is an IEEE 802.3af-compliant Power over Ethernet (PoE) Powered Device (PD) interface IC with integrated current-mode PWM controller for DC/DC conversion. It provides signature detection, power classification, programmable inrush current limiting, adjustable undervoltage lockout, and drives an external N-channel MOSFET via 1.0 A gate driver. It operates across 30–60 V input range and supports up to Class 4 (12.95 W) PD applications in VoIP phones and IP cameras.
For engineers reviewing the MCZ34670EG datasheet, MCZ34670EG pinout, MCZ34670EG application, or MCZ34670EG equivalent, this page delivers verified electrical parameters, validated 20-pin SOICW package mapping, confirmed IEEE 802.3af compliance, real-world soft-start timing, and documented thermal shutdown behavior at 165°C typical.
Technical Context
The MCZ34670EG integrates a full IEEE 802.3af PD interface-including signature resistor detection (25 kΩ), four-class classification (0–4), and isolation switch control-with a current-mode PWM controller featuring leading-edge blanking, internal slope compensation (10–50 mV/µs), and 50% duty cycle limitation. Its dual-supply architecture uses VPWR (up to 80 V) and VIN (negative rail) to support PoE midspan and endspan topologies.
It implements a high-voltage regulator (9.0 V typical VDD output), active-low RESET referenced to VOUT, and isolated feedback support via optocoupler + TLV431 (FB tied to VOUT when used). The CS pin senses voltage across an external sense resistor with 400 mV threshold, while GATE delivers ±1.0 A drive capability into 2 nF load with 50 ns rise time.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 30 V to 60 V operating; absolute max 80 V - supports standard PoE PSE outputs including legacy and 802.3af-compliant sources. |
| IEEE 802.3af Compliance | Fully compliant signature detection (25 kΩ), classification (Class 0–4), and inrush control - enables plug-and-play interoperability with certified PSEs. |
| Switching Frequency | Adjustable 100–400 kHz via resistor on FREQ pin - allows optimization of magnetics size, efficiency, and EMI performance. |
| Current Sense Threshold | 400 mV typical at CS pin - sets peak MOSFET current limit with cycle-by-cycle protection against overloads. |
| Gate Driver Output | ±1.0 A sink/source into 2 nF load - directly drives medium-power external N-MOSFETs without buffer stages. |
| Thermal Shutdown | 165°C typical activation with 30°C hysteresis - protects device during sustained overload or poor heatsinking conditions. |
| UVLO Threshold | Adjustable 25–50 V via UVLO pin; default turn-on at 40 V - ensures reliable startup only after stable PoE supply is established. |
Pinout & Package
MCZ34670EG is housed in a 20-pin SOICW (Small Outline Integrated Circuit, Wide-body) package, Pb-free per EG suffix, rated for -40°C to +85°C ambient operation. Thermal resistance θJA = 103°C/W on standard 4-layer JEDEC board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VPWR (Pins 1,2) | Positive supply input | Connects to most positive PoE rail; supports up to 80 V absolute max - forms high-side path with VOUT for load connection. |
| RCLA (Pin 3) | Classification resistor terminal | Sets PD class (0–4) by resistor to VIN; enables PSE to allocate correct power budget (e.g., 12.95 W for Class 4). |
| UVLO (Pin 4) | Undervoltage lockout control | Adjusts startup threshold; tied to VIN for default 40 V turn-on - prevents erratic operation during brownout or slow PoE ramp-up. |
| FREQ (Pin 7) | Oscillator frequency adjust | Resistor to VIN sets switching frequency between 100–400 kHz - balances efficiency, transformer size, and EMI filtering requirements. |
| ILIM (Pin 8) | Inrush current limit control | Resistor to VIN programs initial inrush limit (65–250 mA) - protects legacy PSEs not meeting 802.3af inrush specs. |
| VIN (Pins 9,10) | Negative supply input | Most negative PoE rail reference; all internal circuitry referenced to this node - completes power loop with VPWR and VOUT. |
| VOUT (Pins 11,12,13) | Power MOSFET drain output | High-current path (Pins 11,12) and low-current path (Pin 13) - connects directly to external MOSFET source and sense resistor. |
| GATE (Pin 19) | External MOSFET gate driver | ±1.0 A drive capability with 50 ns rise/30 ns fall - eliminates need for discrete gate drivers in ≤15 W PD designs. |
| VDD (Pin 20) | Internal regulator output | 9.0 V regulated supply for gate driver; requires ≥10 µF capacitor to VOUT - reduces dependency on auxiliary winding in flyback designs. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated IEEE 802.3af PD interface | Eliminates need for discrete signature resistors, classification circuits, and isolation switches - reduces BOM count by ≥8 components. |
| Programmable inrush current limiting | Three selectable limits (65/110/180 mA) via ILIM resistor - ensures compatibility with non-802.3af PSEs while enabling full-power operation after startup. |
| Current-mode PWM with slope compensation | Stabilizes inner current loop across 100–400 kHz; slope scales with frequency (10–50 mV/µs) - prevents subharmonic oscillation in CCM operation. |
| Active-low RESET output referenced to VOUT | Signals system reset when VSS falls below 0.24 V - enables synchronized restart of downstream logic after UVLO or OVP events. |
| Input overvoltage protection (OVP) | Disables GATE at 66–72 V VPWR and initiates soft-start discharge - protects external MOSFET from transient surges on PoE lines. |
Applications
| VoIP Phones | IP Cameras |
|---|---|
Use Scenario: Powered via Category 5 Ethernet cable from PoE switch in enterprise office environments. IC Role / Device Role / Timing Role: MCZ34670EG serves as primary PD interface and DC/DC controller, managing signature, classification, and 5 V/1.2 A isolated flyback conversion. Use Value: Enables single-cable deployment with <90% efficiency at 1 A load (48 V input), reducing installation cost and eliminating local AC adapters. | Use Scenario: Outdoor surveillance camera requiring robust PoE startup under cold ambient (-40°C) and variable line voltage. IC Role / Device Role / Timing Role: MCZ34670EG performs cold-start signature detection, Class 3 classification (6.49 W), and controls gate drive with 50 ns rise time for fast transient response. Use Value: Adjustable UVLO (25–50 V) ensures reliable operation even with long cable drops causing >5 V IR loss; thermal shutdown at 165°C prevents field failures. |
| Wireless Access Points | Thin Clients |
Use Scenario: Ceiling-mounted 802.11ac AP drawing up to 12.95 W in high-density deployments. IC Role / Device Role / Timing Role: MCZ34670EG executes Class 4 classification, drives external MOSFET at 250 kHz, and regulates 12 V output using optocoupler+TLV431 feedback. Use Value: Slope compensation (25 mV/µs at 250 kHz) stabilizes regulation under dynamic RF load changes; 50% duty cycle limit ensures safe transformer design. | Use Scenario: Fanless desktop thin client powered from PoE-enabled network infrastructure. IC Role / Device Role / Timing Role: MCZ34670EG manages inrush limiting (180 mA), soft-start (controlled by SS capacitor), and provides RESET signal to SoC upon power fault. Use Value: Soft-start ramp prevents output overshoot into sensitive processor rails; RESET output (active-low, VOUT-referenced) guarantees clean boot sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE PD interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT4275IMS#PBF | Single-chip IEEE 802.3af PD with integrated DC/DC controller; supports 100–750 kHz switching; no external MOSFET required. | Enables smaller footprint but lacks programmable inrush limiting and adjustable UVLO - less flexible for legacy PSE integration. | Select LT4275IMS#PBF when board space is critical and only modern 802.3af PSEs are used. |
| TPS23754PWPR | TI PoE PD interface with integrated PWM controller; supports 50–500 kHz; includes synchronous rectifier control and better ESD rating (±4 kV HBM). | Offers higher switching frequency range and improved surge immunity but requires external gate driver for >1 A MOSFET drive. | Select TPS23754PWPR when designing for harsh EMI environments or needing >400 kHz operation. |
Compared with LT4275IMS#PBF and TPS23754PWPR, MCZ34670EG provides superior inrush current programmability and direct 1.0 A gate drive without buffers - making it optimal for cost-sensitive, thermally constrained PoE endpoints where legacy PSE compatibility is required.
Availability
MCZ34670EG is available at Aetrix Electronics and suitable for VoIP phones, IP cameras, wireless access points, and thin clients requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for MCZ34670EG 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
Freescale Semiconductor (now part of NXP Semiconductors) is a global leader in analog and mixed-signal ICs for automotive, industrial, and communications systems.
The MCZ34670EG belongs to Freescale's Power over Ethernet PD controller product line, designed specifically to simplify IEEE 802.3af-compliant endpoint development with integrated power management and robust protection features.
FAQ
What is the maximum input voltage rating for MCZ34670EG?
The MCZ34670EG has an absolute maximum VPWR rating of 80 V, with recommended operating range of 30–60 V per IEEE 802.3af specifications. Exceeding 80 V may cause permanent damage. The device includes overvoltage shutdown that disables the gate driver when VPWR exceeds 66–72 V, providing protection during transients. This dual-layer protection-absolute rating plus active OVP-ensures reliability in real-world PoE deployments where cable-induced spikes can occur.
How does MCZ34670EG implement IEEE 802.3af signature detection?
MCZ34670EG implements IEEE 802.3af signature detection by presenting a valid 25 kΩ resistance between VPWR and VIN during the 2.7–10.1 V detection phase. It uses internal circuitry to compensate for diode voltage drops in bridge rectifiers, ensuring the effective dR remains within the 23.75–26.25 kΩ valid region defined by the standard. The RCLA pin is not involved in signature detection; it is used exclusively for classification current programming after detection succeeds.
Can MCZ34670EG support isolated feedback configurations?
Yes, MCZ34670EG supports isolated feedback using either optocoupler + TLV431 shunt regulator or tertiary winding methods. When using optocoupler feedback, FB is tied to VOUT to disable the internal error amplifier, and COMP supplies bias current through its internal 5.0 kΩ pull-up to 5.0 V. The TLV431-based solution achieves ±1% output regulation accuracy, while tertiary winding offers lower cost but reduced line/load regulation - both are validated in Freescale Application Note AN3279.
What is the purpose of the ILIM pin on MCZ34670EG?
The ILIM pin on MCZ34670EG programs the initial inrush current limit during PoE startup, allowing compatibility with legacy PSEs that cannot handle the full 802.3af inrush specification. Connecting resistors of 12.1 kΩ, 42.2 kΩ, or 191 kΩ between ILIM and VIN sets inrush limits to 180 mA, 110 mA, or 65 mA respectively. After startup, the device transitions to high-level current limiting (380–700 mA), enabling full-power operation under compliant PSEs.
Does MCZ34670EG include thermal protection?
Yes, MCZ34670EG includes thermal shutdown protection that activates at 150–180°C junction temperature (165°C typical), with 30°C hysteresis for recovery. This feature is independent of ambient temperature and triggers when internal power dissipation exceeds safe limits - for example, during sustained overload or inadequate PCB copper area. Once tripped, the device halts switching and holds GATE low until junction temperature falls below the hysteresis threshold, preventing thermal runaway.
MCZ34670EG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Controller (PD), DC/DC
- Number of Channels:
- 1
- Power - Max:
- 13 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 60V (Max)
- Current - Supply:
- 4.5mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
MCZ34670EG FAQ
1.How can I place an order for MCZ34670EG through Aetrix?
Please submit a Request for Quotation (RFQ) for MCZ34670EG 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 MCZ34670EG reliable?
The price and inventory of MCZ34670EG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCZ34670EG is usually 5 days.
3.What payment methods are accepted for MCZ34670EG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCZ34670EG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCZ34670EG?
MCZ34670EG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCZ34670EG 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 MCZ34670EG?
For technical support, including MCZ34670EG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCZ34670EG requirements.
6.How does Aetrix verify that MCZ34670EG is sourced from the original manufacturer or authorized distributors?
All MCZ34670EG 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 MCZ34670EG meets industry standards.
7.What is the process for return or replacement of MCZ34670EG?
All MCZ34670EG units undergo pre-shipment inspection (PSI). If there is an issue with MCZ34670EG, 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 MCZ34670EG part is unused and in its original packaging.
Return procedure for MCZ34670EG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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