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STMicroelectronics ST5R28MTR
- Part No.:
- ST5R28MTR
- Manufacturer:
- STMicroelectronics
- Package:
- SC-74A, SOT-753
- Datasheet:
-
ST5R28MTR.pdf
- Description:
- IC REG BOOST 2.8V 100MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,216
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Product details
Overview
ST5R28MTR from STMicroelectronics is a micropower VFM step-up DC/DC converter optimized for battery-powered systems requiring ultra-low quiescent current (16 µA), regulated 2.8 V output, and start-up from as low as 0.8 V input. It integrates a 850 mΩ internal switch, operates at 150 kHz max switching frequency, and delivers up to 100 mA output current in SOT23-5L package. Typical use includes low-voltage portable devices such as wireless handsets and palmtop computers.
For engineers reviewing the ST5R28MTR datasheet, ST5R28MTR pinout, ST5R28MTR application, or ST5R28MTR equivalent, key selection criteria include verified start-up voltage (0.8–1.2 V), output accuracy (±5%), hold-on voltage (0.6 V), efficiency at 50 mA (82% typ.), and SOT23-5L thermal resistance (63 °C/W).
Technical Context
The ST5R28MTR employs a Voltage-Frequency Modulation (VFM) control architecture with fixed 5 µs on-time and variable off-time governed by error amplifier feedback against an internal bandgap reference. This enables ultra-low supply current under light loads while maintaining regulation across 0–100 mA output range.
Its LX pin drives an external inductor-diode-capacitor network; internal switch RDSON (850 mΩ) and overcurrent limiting ensure safe operation during transient load steps. Bootstrapping allows sustained operation down to 0.6 V input at 1 mA load, independent of diode forward voltage after startup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.8 V ±5% - tightly regulated rail for 2.8 V logic or analog subsystems |
| Supply Current (no load) | 16 µA - enables multi-year battery life in standby-mode devices |
| Start-up Voltage | 0.8–1.2 V - supports single-cell alkaline or NiMH battery startup |
| Hold-on Voltage | 0.6 V - sustains regulation even as battery depletes below 0.8 V |
| Max Oscillator Frequency | 150 kHz - balances EMI control and inductor size for compact designs |
| Internal Switch RDSON | 850 mΩ - limits conduction loss at 100 mA, enabling >82% efficiency |
| Efficiency (IOUT = 50 mA) | 82% typ. - reduces thermal stress and extends runtime in space-constrained layouts |
Pinout & Package
SOT23-5L package: 5-pin surface-mount, 1.45 mm height, 3.0 mm × 1.75 mm footprint, thermal resistance Rthj-case = 63 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Supply | Accepts 0.6–5.5 V; also powers internal circuitry post-startup |
| GND | Ground Reference | Common return for LX switch current and control logic; requires low-impedance plane |
| LX | Switch Node | Drives external inductor; peak current internally limited to ~150 mA |
| VOUT | Regulated Output | Provides 2.8 V output; also serves as internal supply rail for bias circuits |
| NC | No Connect | Internally unconnected; must be left floating or tied to GND per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| VFM Control Architecture | Enables 16 µA quiescent current at no load while maintaining regulation across full load range |
| Bootstrapped Operation | Permits continuous regulation down to 0.6 V input at 1 mA, decoupling hold-on from diode VF |
| Integrated Power Switch | 850 mΩ RDSON reduces external component count and improves efficiency vs discrete FET solutions |
| Minimal External Components | Requires only one inductor (47 µH), one Schottky diode, and two capacitors for full functionality |
| High Switching Frequency | 150 kHz max enables use of small, low-cost inductors without compromising ripple or stability |
Applications
| Wireless Handset Power Rail | Pager Display Backlight Driver |
|---|---|
Use Scenario: Powering 2.8 V RF front-end and baseband ICs in GSM/DECT handsets operating from single-cell alkaline or NiMH batteries. IC Role / Device Role / Timing Role: Primary step-up regulator supplying stable 2.8 V rail; manages dynamic load transients during TX bursts. Use Value: Ultra-low 16 µA quiescent current extends standby time; 0.8 V start-up ensures operation until battery reaches end-of-life. |
Use Scenario: Driving white LED backlight for monochrome LCD in pagers with tight space constraints and long battery life requirements. IC Role / Device Role / Timing Role: Constant-voltage boost source feeding LED current regulator; operates in discontinuous mode at low duty cycle. Use Value: 0.6 V hold-on voltage enables full backlight functionality even when battery drops below 0.8 V; minimal BOM reduces PCB area. |
| Palmtop Computer Core Logic | Low-Power Camera Sensor Bias |
Use Scenario: Generating clean 2.8 V supply for ARM7-based microcontroller core and SRAM in handheld PDAs powered by two AA cells. IC Role / Device Role / Timing Role: Main system power converter; interfaces with battery fuel gauge and low-battery shutdown logic. Use Value: 82% efficiency at 50 mA minimizes heat in sealed enclosure; SOT23-5L footprint saves board space vs larger packages. |
Use Scenario: Providing regulated 2.8 V bias for CMOS image sensor analog front-end in compact digital cameras. IC Role / Device Role / Timing Role: Low-noise, low-ripple voltage source; isolated from digital switching noise via dedicated ground plane. Use Value: Low 16 µA supply current preserves battery between shots; high PSRR suppresses switching artifacts in analog signal path. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX680ESA+ | Charge-pump topology; fixed 5 V output; no inductor required; ISUPPLY = 120 µA | Lower output current (100 mA vs 100 mA), but higher quiescent current and no adjustable output | Select for ultra-small footprints where inductor avoidance outweighs efficiency loss |
| TPS61022DSQR | PFM/PWM hybrid; 2.8 V output option; ISUPPLY = 2.5 µA; higher efficiency (90% @ 50 mA) | Wider input range (0.3–5.5 V); requires different compensation network and layout | Select for longest battery life in new designs where layout redesign is acceptable |
Compared with MAX680ESA+ and TPS61022DSQR, the ST5R28MTR offers superior start-up capability (0.8 V) and proven reliability in legacy portable designs, while trading off some efficiency and quiescent current for robustness and minimal external component count.
Availability
ST5R28MTR is available at Aetrix Electronics and suitable for wireless handsets, pagers, palmtop computers, and low-power camera modules requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for ST5R28MTR 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, MCU, power, and sensor solutions for automotive, industrial, and consumer markets.
The ST5R00 series was developed specifically for ultra-low-power, single-cell battery applications demanding micropower operation, wide input voltage tolerance, and minimal external components - targeting portable electronics with stringent size and runtime constraints.
FAQ
What is the minimum input voltage required for ST5R28MTR to start up?
The ST5R28MTR starts up when the input voltage exceeds 0.8 V (typical) under 1 mA load, measured as VIN minus the forward voltage of the external Schottky diode. This value is confirmed in Table 5 of the datasheet and validated across temperature; it does not depend on output load beyond 1 mA.
Can ST5R28MTR operate with input voltage higher than its output voltage?
Yes - if VIN exceeds 2.8 V, the output follows VIN minus diode drop, but neither VIN nor VOUT may exceed 5.5 V absolute maximum rating. The device remains functional as a pass-through regulator above VOUT, provided internal power dissipation stays within 170 mW limit at 25°C ambient.
Why does ST5R28MTR specify different supply current values across the ST5Rxx family?
Supply current increases slightly (16 → 18 µA) across the ST5Rxx series due to higher internal supply voltage at elevated VOUT settings, which raises bias currents in the error amplifier and oscillator. ST5R28MTR's 16 µA value is measured at VIN with no load and is confirmed in Table 5 under "ISUPPLY" test condition.
Is the NC pin on ST5R28MTR required to be grounded?
No - the NC pin is internally unconnected and must remain floating or be tied to GND only for mechanical stability or EMI reduction per layout best practices. Datasheet Figure 2 and Mechanical Data section confirm no electrical function; grounding it has no effect on regulation or efficiency.
ST5R28MTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 0.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 100mA
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -25°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
ST5R28MTR FAQ
1.How can I place an order for ST5R28MTR through Aetrix?
Please submit a Request for Quotation (RFQ) for ST5R28MTR 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 ST5R28MTR reliable?
The price and inventory of ST5R28MTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST5R28MTR is usually 5 days.
3.What payment methods are accepted for ST5R28MTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST5R28MTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ST5R28MTR?
ST5R28MTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ST5R28MTR 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 ST5R28MTR?
For technical support, including ST5R28MTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST5R28MTR requirements.
6.How does Aetrix verify that ST5R28MTR is sourced from the original manufacturer or authorized distributors?
All ST5R28MTR 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 ST5R28MTR meets industry standards.
7.What is the process for return or replacement of ST5R28MTR?
All ST5R28MTR units undergo pre-shipment inspection (PSI). If there is an issue with ST5R28MTR, 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 ST5R28MTR part is unused and in its original packaging.
Return procedure for ST5R28MTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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