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Monolithic Power Systems Inc. MP8126DR-LF-Z
- Part No.:
- MP8126DR-LF-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Category:
- Special Purpose Regulators
- Package:
- 24-VFQFN Exposed Pad
- Datasheet:
-
MP8126DR-LF-Z.pdf
- Description:
- IC REG CONV LNB 1OUT 24QFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MP8126DR-LF-Z from Monolithic Power Systems is a DiSEqC 1.x–compliant LNB power supply and control-voltage regulator integrating a current-mode boost converter and tracking linear regulator. It delivers up to 550mA at selectable 13V/18V outputs with 1V line-drop compensation, 22kHz tone shaping, and POK monitoring - designed specifically for satellite set-top box RF front-end power delivery over coaxial cable.
For engineers reviewing the MP8126DR-LF-Z datasheet, MP8126DR-LF-Z pinout, MP8126DR-LF-Z application, or MP8126DR-LF-Z equivalent, key selection criteria include DiSEqC-compliant voltage switching, LNB-specific line-drop compensation, integrated 22kHz signal shaping, and thermal shutdown behavior under sustained overload.
Technical Context
The MP8126DR-LF-Z implements a two-stage regulation architecture: a fixed-frequency (342 kHz) peak-current-mode boost converter generates a dynamically tracked VBOOST voltage, enabling the downstream linear regulator to operate near minimum dropout (1.26V typical). This preserves low-noise RF integrity by isolating switching noise from the LNB output path.
Control logic directly supports DiSEqC 1.x functions: dual-polarity voltage selection (13V/18V), programmable line-drop compensation (+1V offset), and EXTM-pin–driven 22kHz tone generation with defined rise/fall time (8 μs) and duty cycle (50%). Overload protection combines dynamic current limiting (50ms on-time, 2s off-time) with thermal shutdown at 150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8V to 14V - matches standard satellite receiver DC bus rails; UVLO threshold at 7V ensures reliable startup. |
| Output Voltage Options | 13V/14V/18V/19V - selectable via 13V/18V and LINEDROP pins for LNB polarization and coax loss compensation. |
| Max Output Current | 550mA - sufficient for dual-LNB or high-gain single-LNB operation; current limit adjustable via ILIMIT resistor. |
| Boost Switching Frequency | 342 kHz - balances EMI filtering requirements and inductor size; pulse-skipping at light load improves efficiency. |
| Line-Drop Compensation | +1V offset when LINEDROP = HIGH - compensates for ≥1.5V IR drop on 50m+ coax runs without external sensing. |
| 22kHz Tone Accuracy | 20–24 kHz range with 0.4–0.8Vpp amplitude and 50% duty cycle - meets DiSEqC 1.x spectral mask and modulation fidelity requirements. |
| Thermal Shutdown | 150°C junction temperature with 20°C hysteresis - prevents permanent damage during sustained short-circuit or ambient overheating. |
Pinout & Package
MP8126DR-LF-Z is housed in a thermally enhanced 24-pin QFN package (4mm × 4mm, 0.5mm pitch) with exposed pad connected to PGND for optimal heat dissipation. Pin mapping follows JEDEC MO-220 VGGD standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 3, 9, 18 | NC | No internal connection; must remain unconnected per datasheet. |
| 2 | VDD | Main input supply (8–14V); powers internal bias circuits and gate drivers. |
| 4 | COMP | Boost regulator compensation node; connects to RC network (47nF/4.7kΩ/470pF) for loop stability. |
| 5 | EN | Active-high enable; controls full device startup/shutdown; requires pull-up if VIN > 6V. |
| 6 | LINEDROP | Logic input enabling +1V output offset to counteract coaxial cable voltage drop. |
| 7 | POK | Open-drain Power OK indicator; asserts LOW when VOUT deviates >±12% from nominal. |
| 8 | 13V/18V | Logic-selectable output voltage mode; HIGH = 18V/19V, LOW = 13V/14V for LNB polarization control. |
| 10 | EXTM | 22kHz tone input; internally shaped and modulated onto VOUT per DiSEqC 1.x timing and amplitude specs. |
| 11 | TCAP | Soft-start timing capacitor node; 7μA charging current sets output ramp rate (e.g., 100nF ≈ 14ms). |
| 12 | ILIMIT | Current limit programming pin; resistor to GND sets trip point (e.g., 10kΩ → ~770mA). |
| 13–14, 15–16 | VOUT / PGND | Main regulated output and dedicated power ground; separate from analog ground (SGND) to minimize noise coupling. |
| 17 | BST | Bootstrap supply for internal LDO driver; requires external capacitor between BST and VBOOST. |
| 19–20, 21 | VBOOST / SW / PGND | Boost stage output, switch node, and power ground - forms high-current path requiring tight layout. |
| 22 | SGND | Analog reference ground; isolated from PGND to prevent switching noise injection into feedback paths. |
| 23–24 | BYPASS | Internal regulator bypass; connects to 5V-rated ceramic capacitor for stable bias voltage. |
Key Features
| Feature | Design Value |
|---|---|
| DiSEqC 1.x Compliance | Integrated 22kHz tone shaper, 13V/18V polarization switching, and line-drop compensation meet EUTELSAT specification without external logic. |
| Two-Stage Low-Noise Regulation | Boost + tracking LDO architecture suppresses switching ripple on VOUT to <20mVpp, preserving LNB RF sensitivity. |
| Programmable Overcurrent Protection | Resistor-set current limit (600–1100mA range) with auto-retry (50ms ON / 2s OFF) enables robust fault recovery in field-deployed systems. |
| Coaxial Cable Loss Compensation | Dedicated LINEDROP pin adds precise +1V offset to VOUT, eliminating need for external voltage-sense feedback across long cable runs. |
| Thermal & Electrical Fault Coverage | Combined over-temperature shutdown (150°C), short-circuit protection, and POK monitoring provide full-system fault visibility for STB firmware. |
Applications
| Satellite Set-Top Box LNB Power | Dual-LNB Switching System |
|---|---|
Use Scenario: Powering a single Ku-band LNB in consumer satellite receivers using a single coaxial cable for both RF signal and DC power delivery. IC Role / Device Role / Timing Role: Provides regulated 13V/18V output and DiSEqC 22kHz tone modulation to select LNB polarization while compensating for cable IR drop. Use Value: Eliminates need for discrete boost + LDO + tone generator ICs, reducing BOM count and PCB area by >40% versus discrete solutions. | Use Scenario: Controlling two independent LNBs (e.g., universal LNB + legacy LNB) via DiSEqC 1.0/1.1 commands in multi-satellite reception systems. IC Role / Device Role / Timing Role: Generates synchronized 13V/18V switching and 22kHz tone bursts to address individual LNBs through a DiSEqC-compatible switch matrix. Use Value: Enables seamless switching between orbital positions without external microcontroller intervention or timing-critical firmware delays. |
| Professional Satellite Receiver Module | Low-Noise RF Front-End Supply |
Use Scenario: Powering high-gain LNB modules in commercial-grade satellite distribution amplifiers where thermal reliability and long-cable operation are critical. IC Role / Device Role / Timing Role: Delivers 550mA at 19V with active line-drop compensation and thermal foldback to sustain operation under 70°C ambient conditions. Use Value: Maintains LNB gain stability over 100m coax runs and prevents thermal shutdown during continuous high-load operation. | Use Scenario: Supplying ultra-low-noise analog circuitry in RF test equipment requiring clean, ripple-free bias voltage derived from noisy DC rails. IC Role / Device Role / Timing Role: Acts as a low-noise post-regulator following a switching pre-regulator, leveraging its tracking architecture to minimize dropout and thermal dissipation. Use Value: Achieves <20mVpp output ripple at full load - 5× lower than standard LDOs - preserving signal-to-noise ratio in sensitive RF measurement paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LNB power supply and control-voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP8124DR-LF-Z | Successor device with improved efficiency (up to 92%), lower quiescent current (3.5mA vs 5mA), and extended temperature range (−40°C to +125°C vs −40°C to +125°C same, but tighter parametric specs). | Same pinout and DiSEqC functionality; optimized for new designs requiring higher efficiency and lower standby power. | Select MP8124DR-LF-Z for new designs; MP8126DR-LF-Z remains viable for legacy replacement or cost-sensitive volume production where existing layout is fixed. |
| LM43603PWPR | Standalone 3.5A synchronous buck regulator (no LDO, no DiSEqC features); requires external tone generator, voltage selector, and line-drop compensation circuitry. | Not DiSEqC-compliant; suitable only for custom LNB power architectures where full feature integration is unnecessary or undesirable. | Choose only if system-level control logic already exists and discrete implementation offers better thermal or cost trade-offs for non-standard LNB configurations. |
Compared with MP8124DR-LF-Z, the MP8126DR-LF-Z provides identical DiSEqC functionality but with higher quiescent current and slightly reduced efficiency; versus LM43603PWPR, it delivers full LNB-specific integration at the cost of less flexibility in non-standard topologies.
Availability
MP8126DR-LF-Z is available at Aetrix Electronics and suitable for satellite set-top boxes, DiSEqC switching systems, and professional LNB distribution modules requiring stable component supply and long-term obsolescence management.
Supply support for MP8126DR-LF-Z 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
Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.
The MP8126 belongs to MPS's satellite communication power management product line, engineered specifically for DiSEqC-compliant LNB power delivery - emphasizing low-noise regulation, coaxial cable loss compensation, and integrated tone generation in compact packages.
FAQ
What is the purpose of the TCAP pin on MP8126DR-LF-Z?
The TCAP pin sets soft-start timing via an external capacitor. A 7μA internal current charges this capacitor, determining output voltage ramp rate. For example, a 100nF capacitor yields ~14ms rise time. Placement must be close to SGND and away from noisy nodes like SW to avoid coupling-induced startup instability.
How does the MP8126DR-LF-Z implement line-drop compensation?
When the LINEDROP pin is driven HIGH, the internal reference shifts to add exactly +1V to the nominal output voltage (e.g., 13V → 14V, 18V → 19V). This compensates for IR drop on long coaxial cables without requiring remote voltage sensing or feedback loops, maintaining LNB operating voltage within specification.
Can MP8126DR-LF-Z drive a 2A LNB?
No. The MP8126DR-LF-Z is rated for up to 550mA continuous output current. Attempting to drive a 2A LNB exceeds its current limit and will trigger dynamic overload protection (50ms on, then 2s shutdown). For higher-current LNBs, consider discrete boost + LDO solutions or higher-capacity regulators like MPQ8126 series variants.
What happens when the POK pin goes LOW?
The POK pin is an open-drain output that pulls LOW when VOUT deviates more than ±12% from its nominal value (e.g., <11.2V or >15.2V for 13V mode). This signals a fault condition - such as overvoltage, undervoltage, or severe load transient - allowing host MCU to initiate corrective action or user alert.
Is MP8126DR-LF-Z pin-compatible with MP8124DR-LF-Z?
Yes. MP8124DR-LF-Z maintains identical pinout, package dimensions, and functional pin assignments as MP8126DR-LF-Z. It is a direct drop-in replacement with improved electrical specs, making it suitable for design refreshes without PCB changes.
Why does MP8126DR-LF-Z use separate SGND and PGND pins?
Separate analog (SGND) and power (PGND) grounds isolate noise-sensitive feedback and bias circuitry from high-current switching paths. Routing PGND traces directly to the exposed pad and keeping SGND connections short and localized prevents switching transients from corrupting regulation accuracy or causing oscillation in the COMP loop.
What is the maximum allowable input voltage for MP8126DR-LF-Z?
The absolute maximum input voltage is 16V, but the recommended operating range is strictly 8V to 14V. Exceeding 14V risks violating the boost stage's safe operating area and may cause premature failure even if below 16V, as specified in the Absolute Maximum Ratings table.
MP8126DR-LF-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 24-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Applications:
- Converter, LNB
- Voltage - Input:
- 8V ~ 14V
- Number of Outputs:
- 1
- Voltage - Output:
- 13V, 14V, 18V, 19V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (4x4)
MP8126DR-LF-Z FAQ
1.How can I place an order for MP8126DR-LF-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP8126DR-LF-Z 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 MP8126DR-LF-Z reliable?
The price and inventory of MP8126DR-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP8126DR-LF-Z is usually 5 days.
3.What payment methods are accepted for MP8126DR-LF-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP8126DR-LF-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP8126DR-LF-Z?
MP8126DR-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP8126DR-LF-Z 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 MP8126DR-LF-Z?
For technical support, including MP8126DR-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP8126DR-LF-Z requirements.
6.How does Aetrix verify that MP8126DR-LF-Z is sourced from the original manufacturer or authorized distributors?
All MP8126DR-LF-Z 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 MP8126DR-LF-Z meets industry standards.
7.What is the process for return or replacement of MP8126DR-LF-Z?
All MP8126DR-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP8126DR-LF-Z, 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 MP8126DR-LF-Z part is unused and in its original packaging.
Return procedure for MP8126DR-LF-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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