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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

STMicroelectronics ST1PS02B1QTR

Name: ST1PS02B1QTR
Brand: STMicroelectronics
SKU: ST1PS02B1QTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ST1PS02B1QTR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 12-UFQFN

Datasheet:: ST1PS02B1QTR.pdf

Description:: IC REG BUCK ADJ 400MA 12TQFN

Quantity:: RFQ Add To RFQ list

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Inventory:5,995

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Product details

Overview

ST1PS02B1QTR from STMicroelectronics is a nano-quiescent (500 nA), synchronous step-down DC-DC converter in TQFN12 package, delivering up to 400 mA output current with 1.8–5.5 V input range and digitally selectable 1.8–2.5 V output (100 mV steps). It integrates Power Good flag, auxiliary load switch (Vout2), and 100% duty cycle operation for ultra-low-power wearable and energy-harvesting systems.

For engineers reviewing the ST1PS02B1QTR datasheet, ST1PS02B1QTR pinout, ST1PS02B1QTR application, or ST1PS02B1QTR equivalent, this page delivers verified technical context, validated pin functions, confirmed efficiency curves at microamp loads, and real-world selection guidance for battery-constrained IoT endpoints.

Technical Context

The ST1PS02B1QTR uses peak current control (PCC) architecture with seamless PFM/PWM transition, enabling stable regulation down to 10 µA load while maintaining 92% efficiency at 10 mA (VIN = 3.6 V, VOUT = 2.5 V). Its hysteretic comparator senses coil ripple current to sustain constant ripple across input and load variations.

It embeds three independent control paths: digital voltage selection (D0–D2) for dynamic VOUT scaling, AUX-controlled soft-started Vout2 load switch (100 mA max, 0.75 Ω typical R_AUX), and CL-pin-adjustable current limit (850 mA typ. default, down to 250 mA with external resistor).

Key Specifications

Parameter	Value and Actual Design Meaning
Quiescent Current	500 nA at VIN = 3.6 V (non-switching), enabling multi-year battery life in always-on wearables
Efficiency	92% at 10 mA load (VIN = 3.6 V, VOUT = 2.5 V), minimizing thermal rise in sealed enclosures
Output Voltage Range	1.8 V to 2.5 V in 100 mV steps via D0/D1/D2 pins - no external resistors required
Input Voltage Range	1.8 V to 5.5 V - supports single-cell Li-ion (2.7–4.2 V), coin cells, and energy harvesters
Output Current	Up to 400 mA continuous - sufficient for BLE SoCs, sensors, and low-power displays
Power Good Threshold	97.5% of selected VOUT - ensures reliable system boot before firmware initialization
Undervoltage Lockout	1.57 V (VIN falling, typ.) - prevents brownout operation during battery depletion
Auxiliary Output	Vout2 provides same regulated rail as VOUT (≤100 mA, 0.75 Ω R_AUX) - enables subsystem power gating

Pinout & Package

TQFN12 (2.0 × 1.7 × 0.55 mm) package with wettable flanks, ECOPACK® compliant, optimized for high-density PCB layouts in space-constrained wearables.

Pin/Terminal	Circuit Role	Design Meaning
AUX	Auxiliary output enable	Logic-high activates Vout2; internal soft-start prevents inrush on subsystem power-up
VIN	Main input supply	1.8–5.5 V input; requires 10 µF low-ESR ceramic bypass capacitor for ripple suppression
SW	Switch node	Connects to 2.2 µH inductor; carries high di/dt switching current - must be routed short and wide
GND	Power and signal ground	Common reference for all analog/digital blocks; thermal pad must be soldered to PCB ground plane
VOUT	Feedback sense input	Direct connection to inductor output node - critical for ±1.5% output accuracy and stability
Vout2	Auxiliary regulated output	Same voltage as VOUT minus R_AUX·I_LOAD; supports independent subsystem power control
PGOOD	Open-drain Power Good flag	High-impedance when VOUT ≥ 97.5% target - requires external pull-up for MCU reset or sequencing
CL	Current limit threshold	Pull-to-GND sets 850 mA default; resistor divider allows precise OCP tuning down to 250 mA
D0–D2	Digital voltage select inputs	Three-bit code selects 1.8–2.5 V in 100 mV steps; dynamically reconfigurable during operation
EN	Enable control	Active-high logic; must not float - ties to host MCU GPIO for full system power management

Key Features

Feature	Design Value
Nano-quiescent operation	500 nA IQ enables >10-year shelf life in coin-cell-powered trackers without shutdown circuitry
Digital VOUT selection	Hardware-configurable 1.8–2.5 V outputs eliminate feedback resistor networks and layout sensitivity
Integrated auxiliary load switch	Vout2 delivers same regulated rail with controlled ramp (400–700 µs) - replaces discrete MOSFET + driver
100% duty cycle mode	Direct VIN-to-VOUT conduction below dropout - extends usable battery range by ~150 mV
Embedded soft-start & discharge	Fixed 1.7 ms startup delay and GND-connected output discharge prevent voltage overshoot and backfeed
Adjustable overcurrent protection	CL pin supports resistor-based current limit tuning (250–850 mA) - matches diverse subsystem load profiles

Applications

Wearable Fitness Tracker

Bluetooth® Low Energy Sensor Node

Use Scenario: Continuous heart-rate monitoring with optical sensor, accelerometer, and BLE radio operating from a 3.7 V Li-ion cell.

IC Role / Device Role / Timing Role: Primary power regulator supplying 1.8 V to sensor hub and 2.5 V to BLE SoC, with dynamic voltage scaling during sleep/wake cycles.

Use Value: 500 nA quiescent current extends battery life to 14+ days between charges; PGOOD enables safe firmware boot sequence.

Use Scenario: Self-powered environmental sensor (temp/humidity/pressure) harvesting energy from ambient light or vibration.

IC Role / Device Role / Timing Role: Step-down regulator converting variable harvester output (2.0–5.0 V) to stable 2.2 V for ultra-low-power MCU and radio.

Use Value: 1.8 V minimum input allows operation down to near-dead battery; 92% efficiency at 10 µA preserves harvested µJ-level energy.

Smart Watch Display Subsystem

Industrial Wireless Temperature Monitor

Use Scenario: Driving segmented LCD or OLED display requiring clean, low-noise 2.5 V rail alongside main processor core voltage.

IC Role / Device Role / Timing Role: Secondary regulator using Vout2 output to power display independently, synchronized to UI refresh timing.

Use Value: Dedicated AUX-controlled Vout2 eliminates cross-talk from digital switching noise; soft-start prevents display flicker at power-on.

Use Scenario: Battery-operated temperature probe deployed in remote industrial locations with 10-year maintenance intervals.

IC Role / Device Role / Timing Role: Main power IC enabling deep-sleep mode (10 µA system current) with fast wake-up via EN pin assertion.

Use Value: Undervoltage lockout at 1.57 V prevents erratic behavior during end-of-life battery sag; ±1.5% VOUT accuracy ensures calibrated sensor readings.

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
TI TPS62840YKAR	Lower IQ (300 nA), but fixed 1.8 V output only; no auxiliary switch or dynamic voltage selection	Suitable for static-rail designs where VOUT never changes; lacks subsystem power gating capability	Select when absolute lowest IQ is critical and voltage flexibility is unnecessary
Analog Devices ADP5302ACBZ-2-R7	Higher IQ (1.2 µA), supports 1.2–3.3 V output via resistor divider; includes integrated LDO post-regulator	Better for noise-sensitive analog sensors, but larger solution size and higher standby loss	Select when ultra-low noise or dual-stage regulation justifies 2.4× higher quiescent current

Compared with TPS62840YKAR and ADP5302ACBZ-2-R7, ST1PS02B1QTR uniquely balances nano-power operation, digital VOUT agility, and integrated auxiliary switching - making it optimal for multi-rail, dynamically scaled wearable systems where board area and battery longevity are co-constrained.

Availability

ST1PS02B1QTR is available at Aetrix Electronics and suitable for wearable fitness trackers, BLE sensor nodes, smart watch display subsystems, and industrial wireless temperature monitors requiring stable component supply across long-lifecycle deployments.

Supply support for ST1PS02B1QTR 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 microcontrollers, power management ICs, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The ST1PS02 series targets ultra-low-power portable electronics, specifically engineered to maximize battery life in space-constrained wearables and energy-harvesting endpoints through nano-quiescent design and minimal external component count.

FAQ

What is the minimum input voltage required for ST1PS02B1QTR to regulate 2.2 V output?

The device enters 100% duty cycle mode when VIN approaches VOUT; regulation is maintained down to VIN = 2.2 V + V_th100%- ≈ 2.4 V (typ.). Below 2.4 V, output follows VIN minus R_DS(on) drop. The undervoltage lockout (1.57 V falling) disables operation entirely below that threshold, but regulation ceases earlier due to dropout constraints.

Can D0, D1, and D2 pins be left unconnected if a fixed 2.2 V output is needed?

No - D0–D2 must be actively driven high or low per Table 7. Floating these pins causes undefined VOUT and potential regulation failure. For 2.2 V output, tie D2=HIGH, D1=LOW, D0=LOW. A pull-up/pull-down network is mandatory; no internal terminations exist.

How does the CL pin adjust current limit, and what resistor value sets 500 mA?

CL pin voltage sets ILIM1 threshold: grounding CL yields 850 mA (typ.); adding a resistor to GND lowers it. Per Table 6, for ST1PS02BQTR at VIN = 3.6 V, R2 = 1 MΩ gives 650 mA typ., and R2 = 2.2 MΩ gives 250 mA typ. To achieve ~500 mA, interpolate: use ≈1.5 MΩ resistor between CL and GND.

Is the Vout2 auxiliary output internally discharged when AUX is low?

Yes - when AUX is pulled low, the internal discharge MOSFET (R_disc2 = 30–50 Ω) actively pulls Vout2 to GND. This prevents back-powering of disabled subsystems and ensures clean power sequencing. Discharge occurs within microseconds after AUX deassertion, as confirmed in Figure 24.

ST1PS02B1QTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 12-UFQFN

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):: 1.8V

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 1.8V

Voltage - Output (Max):: 2.5V

Current - Output:: 400mA

Frequency - Switching:: 2MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 12-TQFN (1.7x2)

ST1PS02B1QTR FAQ

1.How can I place an order for ST1PS02B1QTR through Aetrix?

Please submit a Request for Quotation (RFQ) for ST1PS02B1QTR 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 ST1PS02B1QTR reliable?

The price and inventory of ST1PS02B1QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ST1PS02B1QTR is usually 5 days.

3.What payment methods are accepted for ST1PS02B1QTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ST1PS02B1QTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ST1PS02B1QTR?

ST1PS02B1QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ST1PS02B1QTR 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 ST1PS02B1QTR?

For technical support, including ST1PS02B1QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ST1PS02B1QTR requirements.

6.How does Aetrix verify that ST1PS02B1QTR is sourced from the original manufacturer or authorized distributors?

All ST1PS02B1QTR 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 ST1PS02B1QTR meets industry standards.

7.What is the process for return or replacement of ST1PS02B1QTR?

All ST1PS02B1QTR units undergo pre-shipment inspection (PSI). If there is an issue with ST1PS02B1QTR, 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 ST1PS02B1QTR part is unused and in its original packaging.

Return procedure for ST1PS02B1QTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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