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STMicroelectronics PM8903TR
- Part No.:
- PM8903TR
- Manufacturer:
- STMicroelectronics
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
PM8903TR.pdf
- Description:
- IC REG BUCK ADJ 3A 16VFQFPN
- Quantity:
- Payment:
- Shipping:
Inventory:3,417
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Product details
Overview
PM8903TR from STMicroelectronics is a monolithic synchronous step-down DC-DC switching regulator delivering up to 3 A continuous output current, operating from 2.8 V to 6 V input voltage (VIN), with adjustable output down to 0.6 V, ±1% output voltage accuracy, and 1.1 MHz fixed switching frequency. It integrates dual 35 mΩ nMOS power switches and supports interleaved synchronization for CPU/FPGA subsystem power rails.
For engineers reviewing the PM8903TR datasheet, PM8903TR pinout, PM8903TR application, or PM8903TR equivalent, key selection criteria include its thermally compensated lossless current sense, PSKIP light-load efficiency mode, embedded bootstrap diode, Power Good output, and VFQFPN16 3 × 3 mm compact package for space-constrained power delivery.
Technical Context
The PM8903TR implements voltage-mode control with an external compensation network (COMP/FB), enabling wide filter flexibility including all-MLCC designs. Its error amplifier delivers 120 dB DC gain and 14 MHz GBWP for fast transient response under dynamic load conditions typical in processor core supplies.
It features dual-threshold overcurrent protection (IOC1 = 4.6 A typ., IOC2 = 5.2 A typ.), precise OVP/UVP thresholds referenced to the 0.6 V internal bandgap (0.72 V / 0.48 V), and integrated soft-start (0.79 ms) with low-side-less startup to prevent negative output undershoot during pre-biased conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A continuous - supports high-current digital loads like FPGA I/O banks or DSP cores without external current sharing. |
| Input Voltage Range | 2.8 V to 6 V - compatible with single-cell Li-ion, USB PD, and intermediate bus architectures. |
| Output Voltage Accuracy | ±1% over line/load/temperature - ensures stable core voltage regulation across industrial temperature range (–25 °C to +125 °C). |
| Switching Frequency | 1.1 MHz typical - enables use of small, low-profile inductors (e.g., 0.47 µH) and reduces EMI fundamental frequency. |
| HS/LS RDS(on) | 35 mΩ each - minimizes conduction losses at full load; achieves >90% efficiency at 3 A with 3.3 VIN/1.5 VOUT. |
| Quiescent Current | <15 µA in shutdown - critical for battery-backed subsystems requiring ultra-low standby power. |
| Protection Features | OVP, UVP, OTP, OC (dual-level), UVLO on VIN/VCC - provides autonomous fault containment without external supervision circuitry. |
Pinout & Package
PM8903TR is housed in a thermally enhanced VFQFPN16 3 × 3 mm package with exposed thermal pad connected to PGND. The 16-pin layout supports high-current routing and efficient PCB heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN | Enable control input | Active-high logic input with 1.5 V turn-on threshold; internally pulled up to VCC; forces shutdown <15 µA IQ when pulled low. |
| 2 SYNCH | Synchronization interface | Configurable master/slave pin; enables 180° out-of-phase interleaving with second PM8903TR to reduce input ripple RMS current. |
| 3 PGOOD | Open-drain status output | Asserts low if FB voltage exits 0.45–0.75 V window or protection triggers; requires external pull-up for system monitoring. |
| 4 BOOT | Bootstrap supply node | Connects via 0.1 µF ceramic capacitor to PHASE; powers high-side gate driver; eliminates need for external bootstrap diode. |
| 5–7 PHASE | Power switch node | Common connection point for HS source and LS drain; directly interfaces with output inductor; carries full switching current. |
| 8 PSKIP/MS | Multi-function configuration pin | Resistor-to-GND sets PSKIP enable/disable, master/slave role, and switching frequency (0.8/1.0/1.1 MHz). |
| 9 COMP | Error amplifier output | Drives external RC+CP compensation network; determines loop stability and transient response bandwidth. |
| 10 FB | Feedback input | Inverting input of error amp; senses output via resistor divider; 100 nA internal bias prevents floating-induced OVP. |
| 11 GND | Analog ground reference | Reference for internal bandgap, error amp, and logic; must connect to clean signal ground plane, separate from PGND. |
| 12 VCC | Logic supply input | 2.9–5.5 V bias rail for control circuitry; requires ≥1 µF MLCC bypass to GND near pin. |
| 13–14 VIN | Main power input | 2.8–6 V input connected to HS drain; requires ≥10 µF MLCC bypass to PGND pins adjacent to package. |
| 15–16 PGND | Power ground return | Low-impedance return path for LS source and internal power stage; must tie to thermal pad and dedicated PGND plane. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 35 mΩ HS/LS MOSFETs | Eliminates external power switches and associated gate drivers, reducing BOM count and layout complexity for 3 A VR solutions. |
| Thermally compensated lossless current sense | Enables accurate overcurrent detection across –25 °C to +125 °C junction range without external sense resistors or calibration. |
| Pulse-skipping (PSKIP) mode | Boosts light-load efficiency by skipping switching cycles while maintaining regulation-critical for always-on subsystems. |
| Interleaving synchronization support | Allows two PM8903TRs to operate 180° out-of-phase, halving input capacitor RMS current and enabling smaller, lower-cost input filters. |
| Low-side-less soft-start | Prevents negative output voltage undershoot during startup into pre-biased rails-essential for hot-swap and multi-rail sequencing. |
Applications
| Mobile Application Processor Core Supply | FPGA I/O Bank Power |
|---|---|
|
Use Scenario: Powering ARM Cortex-A series CPU cores requiring tightly regulated 0.8–1.2 V at up to 3 A with fast load transients. IC Role / Device Role / Timing Role: Primary synchronous buck regulator providing core VDD; manages dynamic voltage scaling (DVS) via FB divider. Use Value: ±1% output accuracy and 14 MHz GBWP error amp ensure <50 mV droop under 2 A/µs load steps, meeting SoC AVS requirements. |
Use Scenario: Delivering configurable 1.2–3.3 V to FPGA I/O banks with independent voltage domains and sequencing constraints. IC Role / Device Role / Timing Role: Independent point-of-load regulator per bank; EN and PGOOD enable safe power-up/down sequencing. Use Value: Soft-start (0.79 ms) and soft-off with 100 Ω bleed resistor allow controlled ramp-up/ramp-down, preventing I/O latch-up or bus contention. |
| Distributed Telecom Subsystem Rail | Industrial PLC Digital I/O Module |
|
Use Scenario: Generating isolated 3.3 V or 5 V auxiliary rails from 48 V intermediate bus using discrete DC-DC stages. IC Role / Device Role / Timing Role: Secondary-stage buck converter downstream of primary isolation; operates from local 5–6 V intermediate rail. Use Value: 2.8–6 V input range and 1.1 MHz operation enable compact, high-density design with minimal magnetics footprint. |
Use Scenario: Powering microcontroller, CAN transceiver, and opto-isolated digital inputs/outputs in harsh industrial environments. IC Role / Device Role / Timing Role: Main 3.3 V system rail regulator; OTP, OVP, and UVP protections ensure fail-safe behavior during brownouts or sensor faults. Use Value: Full protection suite (including feedback disconnection detection) eliminates need for external supervisor ICs in safety-critical modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Texas Instruments TPS54332 | 3 A, 3.5–28 V input, 570 kHz fixed freq, no integrated bootstrap diode, requires external high-side driver support. | Lacks PSKIP mode and interleaving sync; lower light-load efficiency; larger solution size due to external components. | Choose for higher VIN applications (>6 V); avoid where board space or light-load efficiency is constrained. |
| Analog Devices ADP2384 | 4 A, 4.5–20 V input, 600 kHz/1.2 MHz selectable, no thermally compensated current sense, uses external sense resistor. | Higher current rating but less accurate OCP over temperature; lacks low-side-less startup and feedback disconnect protection. | Prefer for higher-output-current needs; not suitable for pre-biased startup or unattended industrial deployments. |
Compared with TPS54332 and ADP2384, PM8903TR offers superior integration (embedded bootstrap diode, lossless sensing), tighter output accuracy (±1%), and robust system-level protections-making it optimal for compact, high-reliability 3 A POL designs below 6 V input.
Availability
PM8903TR is available at Aetrix Electronics and suitable for mobile processor core supplies, FPGA I/O power, and distributed telecom subsystems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for PM8903TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, microcontroller, and sensor solutions for automotive, industrial, and consumer markets.
The PM8903TR belongs to ST's Power Management IC portfolio, engineered specifically for high-efficiency, space-constrained point-of-load regulation in portable and embedded systems demanding robust protection and seamless power sequencing.
FAQ
What is the minimum output voltage achievable with PM8903TR?
The PM8903TR supports output voltages down to 0.6 V, set by its internal precision 0.6 V reference and adjustable feedback divider. With proper resistor selection on the FB pin, outputs as low as 0.6 V are achievable with ±1% accuracy across temperature and load, making it suitable for modern low-voltage processor cores and ASICs.
How does the PSKIP/MS pin configure switching frequency?
The PSKIP/MS pin selects switching frequency via resistor-to-GND: 0 Ω → 1.1 MHz, 24 kΩ → 1.0 MHz, 180 kΩ → 0.8 MHz, or floating → 1.1 MHz default. This same pin also enables/disables pulse-skipping and defines master/slave status for interleaving-no additional configuration pins required.
Can PM8903TR safely start into a pre-biased output?
Yes. The PM8903TR implements low-side-less soft-start: during startup, the low-side MOSFET remains disabled until the first PWM pulse occurs, preventing reverse current flow and negative output undershoot-even when powering into a pre-charged rail. This is confirmed in Section 5.2.1 of the datasheet.
What thermal performance can be expected in a standard 4-layer PCB layout?
On the official ST demonstration board (4-layer, 2 oz copper, 1-in² thermal pad area), PM8903TR achieves RthJA = 30 °C/W. With proper thermal pad soldering to a dedicated PGND plane and 2–4 thermal vias, junction temperature stays below 125 °C at 3 A continuous load with 3.3 VIN/1.2 VOUT at 25 °C ambient.
PM8903TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.8V
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 6V
- Current - Output:
- 3A
- Frequency - Switching:
- 1.1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -25°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-VFQFPN (3x3)
PM8903TR FAQ
1.How can I place an order for PM8903TR through Aetrix?
Please submit a Request for Quotation (RFQ) for PM8903TR 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 PM8903TR reliable?
The price and inventory of PM8903TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PM8903TR is usually 5 days.
3.What payment methods are accepted for PM8903TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PM8903TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PM8903TR?
PM8903TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PM8903TR 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 PM8903TR?
For technical support, including PM8903TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PM8903TR requirements.
6.How does Aetrix verify that PM8903TR is sourced from the original manufacturer or authorized distributors?
All PM8903TR 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 PM8903TR meets industry standards.
7.What is the process for return or replacement of PM8903TR?
All PM8903TR units undergo pre-shipment inspection (PSI). If there is an issue with PM8903TR, 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 PM8903TR part is unused and in its original packaging.
Return procedure for PM8903TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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