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Monolithic Power Systems Inc. MP8861GL-Z
- Part No.:
- MP8861GL-Z
- Manufacturer:
- Monolithic Power Systems Inc.
- Package:
- 14-PowerVFQFN
- Datasheet:
-
MP8861GL-Z.pdf
- Description:
- IC REG BUCK ADJ 6A 14QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,622
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Product details
Overview
MP8861GL-Z from Monolithic Power Systems is a synchronous step-down DC/DC converter delivering 6A continuous output current with I²C-based telemetry and programmability. It operates across a 2.85V–18V input range, supports 0.6V–5.5V adjustable output voltage via FB pin or 0.6V–1.108V fine-tuned reference via I²C (4mV steps), and integrates constant-on-time (COT) control for fast transient response in SSD power rails and distributed server supplies.
For engineers reviewing the MP8861GL-Z datasheet, MP8861GL-Z pinout, MP8861GL-Z application, or MP8861GL-Z equivalent, key selection considerations include I²C-configurable slew rate, ±1% reference accuracy, 5% I²C-monitored output voltage/current, hiccup-mode OCP, and QFN-14 (3mm×4mm) thermal performance with θJA = 48°C/W.
Technical Context
The MP8861GL-Z implements constant-on-time (COT) control with internal ramp compensation-enabling stable operation with ceramic output capacitors without external ESR dependency. Its dual-FET synchronous architecture uses integrated high-side (29 mΩ RDS(ON)) and low-side (14 mΩ RDS(ON)) MOSFETs, with dead-time control to prevent shoot-through.
I²C interface (up to 3.4 MHz) enables real-time configuration of output voltage, switching frequency (400–600 kHz default, adjustable via register D[5:4]), current limit (8.5 A valley limit), PFM/PWM mode, soft-start time, and power-good deglitch (30 μs). Four selectable I²C addresses (61H–67H) support multi-rail telemetry in dense PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.85V to 18V - supports 3.3V, 5V, 12V, and 15V intermediate bus architectures without external pre-regulation. |
| Output Current | 6A continuous - sustains full load at TJ ≤ 125°C with QFN-14 package and proper PCB copper area. |
| Reference Accuracy | ±1% at +25°C, ±1.5% over –40°C to +125°C - ensures tight VOUT regulation for DDR memory and FPGA core rails. |
| I²C Monitoring Accuracy | ±5% for VOUT and IOUT readings - enables system-level telemetry without external ADCs or current-sense amplifiers. |
| Switching Frequency | 400–600 kHz (default), adjustable via I²C register - balances efficiency, inductor size, and EMI in space-constrained applications. |
| Thermal Shutdown | 160°C with 20°C hysteresis - protects against sustained overload or poor heatsinking while allowing recovery without manual reset. |
| Power Good (PG) | Open-drain, 0.4V max @ 4mA sink - asserts only when VOUT is within ±10% of target (0.81–1.09×VREF UV/OV thresholds). |
Pinout & Package
MP8861GL-Z is housed in a thermally enhanced QFN-14 package (3mm × 4mm, 0.5mm pitch) with exposed thermal pad. Pin 14 (AGND) and Pin 8 (PGND) must be connected to a common ground plane using multiple vias to minimize thermal resistance (θJC = 11°C/W) and ensure stable regulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 BST | Bootstrap supply | Connect 0.1μF ceramic capacitor between BST and SW to bias high-side gate driver above VIN. |
| 2 SW | Switch node | High-current AC node; requires wide copper trace and minimized loop area to reduce EMI and voltage spikes. |
| 3 SCL | I²C clock input | HS-mode compatible (up to 3.4 MHz); internal pull-up not provided - external 2.2kΩ to VCC required. |
| 4 SDA | I²C data bidirectional | Open-drain; shares same pull-up as SCL; supports multi-master arbitration and repeated START. |
| 5 EN | Enable control | 1.5MΩ internal pull-down; accepts up to 18V - direct connection to VIN enables automatic startup. |
| 6 A0 | I²C address select | Voltage divider from VCC sets one of four I²C addresses (61H–67H); threshold voltages defined per datasheet. |
| 7 PG | Power good indicator | Open-drain output; de-asserted if VOUT falls below 0.85×VREF or exceeds 1.05×VREF (deglitched 30μs). |
| 8 PGND | Power ground reference | Primary return path for output current; must be tied directly to AGND and thermal pad with ≥4 vias. |
| 9 VIN | Main input supply | 2.85–18V input; decouple with ≥10μF X5R/X7R ceramic close to pin; wide trace minimizes IR drop. |
| 10 VOUT | Output voltage sense | Direct connection to load positive terminal - improves regulation accuracy under PCB trace resistance. |
| 11 FB | Feedback input | Connects to resistor divider from VOUT to GND; sets nominal VOUT = 0.6V × (1 + R1/R2); supports up to 5.5V. |
| 12 SS | Soft-start timing | Capacitor to GND sets ramp time; typical 1ms/μF; prevents inrush current and output overshoot at startup. |
| 13 VCC | Internal LDO output | 3.5V regulated supply for internal circuitry; requires 0.47μF ceramic decoupling; tracks VIN if <3.5V. |
| 14 AGND | Analog ground | Signal reference for FB, SS, A0, SCL/SDA; must be shorted to PGND on PCB to avoid ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated telemetry via I²C | Real-time readback of VOUT and IOUT with ±5% accuracy eliminates need for external monitoring ICs in server PMBus designs. |
| Programmable reference voltage | 0.6V–1.108V in 4mV steps allows precise core voltage tuning for ASICs/FPGAs without resistor changes. |
| Adjustable slew rate control | I²C-configurable dV/dt prevents excessive inrush during dynamic VOUT updates in adaptive voltage scaling (AVS) systems. |
| Hiccup-mode over-current protection | Auto-retry after fault clears - maintains system uptime during transient overloads (e.g., SSD write bursts) without latch-off. |
| Ceramic-capacitor optimized COT control | Internal ramp compensation enables use of low-ESR ceramic output caps - reduces BOM count, footprint, and output ripple vs. electrolytic solutions. |
Applications
| Solid-State Drive (SSD) Power Rail | Flat-Panel Display Logic Supply |
|---|---|
|
Use Scenario: Powers NAND flash controller and DRAM cache in M.2 and U.2 SSDs with dynamic load steps up to 6A. IC Role / Device Role / Timing Role: Primary synchronous buck regulator with I²C telemetry for health monitoring and firmware-controlled voltage scaling. Use Value: ±1% reference accuracy and 5% I²C current readback enable predictive wear-leveling algorithms and thermal throttling decisions. |
Use Scenario: Supplies 1.2V/3A logic rail for TCON (timing controller) and scaler ICs in 4K LCD/LED TVs. IC Role / Device Role / Timing Role: High-efficiency, low-noise step-down converter with soft-start and PG signaling for safe power sequencing. Use Value: Open-drain PG output synchronizes with display firmware boot sequence; COT control suppresses visible frame artifacts during brightness transitions. |
| Distributed Server Power System | Network Equipment Intermediate Bus |
|
Use Scenario: Provides 3.3V/6A intermediate bus for PCIe add-in cards and baseboard management controllers (BMC) in 1U servers. IC Role / Device Role / Timing Role: Digitally programmable point-of-load (POL) regulator supporting PMBus-compatible telemetry and dynamic reconfiguration. Use Value: Four I²C addresses allow up to four MP8861GL-Z units on one bus - simplifying inventory and enabling per-rail diagnostics in multi-POL systems. |
Use Scenario: Generates 5V/4A auxiliary supply for PHYs, SerDes, and fan controllers in enterprise switches and routers. IC Role / Device Role / Timing Role: Wide-input buck converter with 18V absolute max rating - withstands 12V bus transients and hot-swap events. Use Value: 160°C thermal shutdown with 20°C hysteresis ensures graceful degradation during airflow loss or dust-clogged heatsinks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS546B24A | Higher Vin (4.5–18V), 10A output, PMBus 1.3 compliant, but no integrated telemetry ADC - requires external current sense. | Targeted at high-end servers with strict PMBus compliance; lacks MP8861GL-Z's 2.85V start-up and ceramic-capacitor optimization. | Select when PMBus 1.3 protocol stack and >6A current are mandatory; avoid if low-Vin start-up (<3V) or minimal BOM count is critical. |
| RTQ2134B-QA | Automotive-grade AEC-Q100, 4.5–18V input, 4A output, I²C telemetry, but fixed 0.6V reference - no programmable VREF. | Designed for infotainment and ADAS domain controllers; lacks MP8861GL-Z's wide 2.85V–18V range and 6A capability. | Select for automotive environments requiring AEC-Q100 qualification; avoid for industrial SSD or consumer display applications needing sub-3V start-up. |
Compared with TPS546B24A and RTQ2134B-QA, MP8861GL-Z uniquely combines ultra-wide input range (2.85V–18V), 6A output, I²C-programmable reference (0.6V–1.108V), and ceramic-capacitor stability - making it optimal for cost-sensitive, space-constrained SSD and display power designs where flexibility and integration outweigh protocol strictness or automotive qualification.
Availability
MP8861GL-Z is available at Aetrix Electronics and suitable for solid-state drive (SSD) power rails, flat-panel display logic supplies, distributed server power systems, and network equipment intermediate buses requiring stable component supply, long-term lifecycle support, and consistent parametric performance.
Supply support for MP8861GL-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 MP8861 belongs to MPS's high-efficiency, digitally configurable DC/DC converter product line-engineered specifically for applications demanding telemetry, wide input range, and compact layout in storage, computing, and visual display systems.
FAQ
What is the minimum input voltage required for MP8861GL-Z to start switching?
The MP8861GL-Z has an input UVLO rising threshold of 2.65V (typical), with a guaranteed minimum of 2.45V. It begins switching once VIN exceeds this threshold and EN is asserted. The device supports full operation down to 2.85V, making it suitable for battery-backed or low-voltage intermediate bus applications where other 3V-rated converters would brown out.
Can MP8861GL-Z regulate output voltages above 1.108V?
Yes - while the I²C-programmable reference is limited to 0.6V–1.108V, the FB pin supports external resistor dividers to set VOUT up to 5.5V. For example, a 1.2V output is achieved by configuring R1/R2 such that VOUT = 0.6V × (1 + R1/R2) = 1.2V. This analog feedback path remains fully functional alongside I²C telemetry.
How does the MP8861GL-Z handle pre-biased outputs during startup?
When the output is pre-biased (e.g., back-fed from another rail), the MP8861GL-Z disables both high-side and low-side FETs until the internal soft-start voltage exceeds the sensed FB voltage. This prevents reverse current flow and potential damage to upstream sources, ensuring safe hot-plug and multi-rail sequencing in complex power systems.
What is the maximum I²C bus capacitance supported by MP8861GL-Z?
The MP8861GL-Z supports up to 400pF total bus capacitance on SDA/SCL lines, as verified in I²C electrical characteristics testing. At 400pF, rise/fall times remain within I²C HS-mode limits (≤300ns), enabling reliable communication across dense, multi-device boards without signal integrity compromises.
Does MP8861GL-Z support forced PWM mode under light load?
Yes - the I²C Mode bit (register 01, bit D0) controls light-load behavior: setting it to '1' forces continuous PWM operation regardless of load, eliminating audible noise and output voltage ripple associated with PFM skip mode. This is essential for noise-sensitive analog circuits or real-time systems requiring deterministic switching timing.
What thermal derating applies to the 6A output rating?
The 6A rating is specified at TA = +25°C with adequate PCB copper (≥4 cm² 2oz copper, 4+ thermal vias to inner ground plane). At +85°C ambient, output current derates to ~4.5A due to thermal limits (TJ max = 125°C, θJA = 48°C/W). Derating curves are provided in Figure 8 of the datasheet for precise system-level thermal modeling.
Is the BST capacitor required even when operating at low duty cycles?
Yes - the BST capacitor (0.1μF X7R ceramic) is mandatory for all operating conditions. It forms the floating supply for the high-side gate driver. Omitting it causes immediate failure of the HS-FET gate drive, resulting in no switching and potential thermal runaway due to uncontrolled LS-FET conduction.
MP8861GL-Z Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Monolithic Power Systems Inc.
- Series:
- -
- Package/Case:
- 14-PowerVFQFN
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.85V
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 5.5V
- Current - Output:
- 6A
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-QFN (3x4)
MP8861GL-Z FAQ
1.How can I place an order for MP8861GL-Z through Aetrix?
Please submit a Request for Quotation (RFQ) for MP8861GL-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 MP8861GL-Z reliable?
The price and inventory of MP8861GL-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP8861GL-Z is usually 5 days.
3.What payment methods are accepted for MP8861GL-Z?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP8861GL-Z transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MP8861GL-Z?
MP8861GL-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MP8861GL-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 MP8861GL-Z?
For technical support, including MP8861GL-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP8861GL-Z requirements.
6.How does Aetrix verify that MP8861GL-Z is sourced from the original manufacturer or authorized distributors?
All MP8861GL-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 MP8861GL-Z meets industry standards.
7.What is the process for return or replacement of MP8861GL-Z?
All MP8861GL-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP8861GL-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 MP8861GL-Z part is unused and in its original packaging.
Return procedure for MP8861GL-Z:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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