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Renesas ISL9123II2Z-T
- Part No.:
- ISL9123II2Z-T
- Manufacturer:
- Renesas
- Package:
- 8-UFBGA, WLCSP
- Datasheet:
-
ISL9123II2Z-T.pdf
- Description:
- IC REG BUCK ADJ 600MA 8WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:1,828
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Product details
Overview
ISL9123II2Z-T from Renesas Electronics is an ultra-low quiescent current (950nA) I²C-programmable buck switching regulator in an 8-bump WLCSP (1.8mm×1.0mm), delivering up to 600mA output current with 0.4V–5.375V adjustable output voltage. It features adaptive frequency hysteretic control, automatic and forced bypass modes, and integrated soft-start for power-sensitive wearable and IoT applications.
For engineers reviewing the ISL9123II2Z-T datasheet, ISL9123II2Z-T pinout, ISL9123II2Z-T application, or ISL9123II2Z-T equivalent, key selection criteria include its 950nA regulation IQ, I²C-adjustable VOUT (±2.5% accuracy at 2.1V), 8-bump WLCSP footprint, forced bypass mode (140nA), and hysteretic PWM architecture optimized for micro-power battery operation.
Technical Context
The ISL9123II2Z-T implements a hysteretic PWM controller with internal P- and N-channel MOSFETs (rDSON = 95/100 mΩ typ), supporting seamless PFM/PWM transition and dynamic voltage scaling via I²C. Its adaptive frequency operation enables high efficiency across 10µA–600mA loads without external compensation.
It operates across 1.8V–5.5V input, delivers regulated output down to 0.4V, and includes undervoltage lockout (1.791V), thermal shutdown (140°C), hiccup-mode overcurrent protection, and programmable soft-start ramp rate (3.125 mV/µs default). The device supports standalone operation with POR-default VOUT and full I²C register control (VSET, CONV_CFG, INTFLG).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Quiescent Current | 950nA in regulation mode - enables multi-year battery life in always-on wearables and sensors. |
| Output Voltage Range | 0.4V to 5.375V - supports core logic, RF, and analog rails across diverse SoCs and MCUs. |
| Max Output Current | 600mA (VIN > 2.5V) - sufficient for ARM Cortex-M4/M33 cores, BLE radios, and display drivers. |
| Input Voltage Range | 1.8V to 5.5V - compatible with single-cell Li-ion, Li-poly, and 3.3V/5V system rails. |
| Accuracy @ 2.1V | ±2.5% (forced PWM, 0A load) - ensures stable supply for voltage-sensitive ADCs and PLLs. |
| Package | 1.8mm × 1.0mm 8-bump WLCSP - minimizes PCB area for space-constrained earbuds and smart bands. |
| I²C Interface | Fast-mode (400kHz) - enables real-time dynamic voltage scaling and fault monitoring in firmware. |
Pinout & Package
ISL9123II2Z-T uses an 8-bump Wafer-Level Chip-Scale Package (WLCSP) with 0.4mm pitch, measuring 1.8mm × 1.0mm. The package is designed for low-inductance, high-density placement on ultra-thin flex PCBs typical in wearables.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (A1) | Ground reference | Primary return path for power and signal; must be connected to low-impedance ground plane. |
| VSW (A2) | Auxiliary switched output | Provides independent 3.6V-capable auxiliary rail (ISL9123/A only); leave floating if unused. |
| LX (B1) | Switch node | Connects to external 1µH inductor; requires tight layout to minimize EMI and switching losses. |
| VOUT (B2) | Regulated output | Main buck output; decoupled with ≥6µF effective capacitance (e.g., 22µF 0603 ceramic). |
| VIN (C1) | Input supply | Accepts 1.8V–5.5V; requires ≥5µF input capacitance close to VIN pin. |
| EN (C2) | Enable control | Active-high logic input; must be pulled HIGH to enable; minimum 50µs LOW pulse required for disable. |
| SCL (D1) | I²C clock | Fast-mode (400kHz) interface clock; pull-down to GND if unused. |
| SDA (D2) | I²C data | Open-drain bidirectional data line; pull-down to GND if unused. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low IQ regulation | 950nA enables >10-year shelf life and multi-month runtime in coin-cell-powered IoT sensors. |
| Forced Bypass mode | 140nA IQ and direct conduction path - ideal for low-noise, zero-switching scenarios when VIN ≈ VOUT. |
| Hysteretic PWM control | No external compensation needed; maintains stability across wide load and input ranges with minimal components. |
| I²C programmability | Full register access (VSET, CONV_CFG, INTFLG) enables firmware-controlled DVS, fault logging, and startup tuning. |
| Soft-start ramp control | Programmable 0.78–6.25 mV/µs ramp rate prevents inrush current and avoids brownout during wake-up. |
| Integrated protection | Hiccup-mode OCP (100ms retry), thermal shutdown (140°C), and UVLO ensure robustness in unattended deployments. |
Applications
| Smart Wearables | Wireless Audio |
|---|---|
Use Scenario: Power management in compact smartwatches with dual-core MCU, OLED display, and motion sensor. IC Role / Device Role / Timing Role: Primary buck regulator supplying 1.2V core and 3.3V I/O rails with dynamic voltage scaling. Use Value: 950nA IQ extends battery life to 7+ days between charges; 8-bump WLCSP fits under curved watch bezels. |
Use Scenario: Dual-rail supply for Bluetooth LE audio SoC and MEMS microphone in true wireless earbuds. IC Role / Device Role / Timing Role: Adjustable buck delivering 0.85V DSP core and 1.8V radio LDO input, controlled via host I²C. Use Value: Forced bypass mode eliminates switching noise during audio playback; ±2.5% accuracy ensures codec stability. |
| IoT Edge Sensors | Portable Medical Monitors |
Use Scenario: Battery-powered water meter with ultrasonic flow sensing, LoRaWAN radio, and EEPROM logging. IC Role / Device Role / Timing Role: Single-chip power solution enabling 10-year operation on CR2477 cell via ultra-low IQ and deep-sleep optimization. Use Value: 7nA shutdown current and auto-bypass reduce average system power to sub-µA; I²C allows firmware calibration updates. |
Use Scenario: Clinical-grade pulse oximeter with optical front-end, analog signal chain, and BLE telemetry. IC Role / Device Role / Timing Role: Precision 2.1V supply for ADC reference and 3.3V rail for digital logic, with soft-start preventing measurement corruption. Use Value: ±2.5% VOUT accuracy at 2.1V ensures <0.1% ADC gain error; hiccup-mode OCP prevents thermal drift during extended use. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISL9123IITZ | Factory-programmed fixed 1.9V output; same IQ, package, and I²C capability but no runtime VOUT adjustment. | Used where firmware control of output voltage is unnecessary (e.g., dedicated sensor supply). | Select ISL9123IITZ for simplified BOM and reduced firmware overhead in static-voltage designs. |
| MAX77650AWE+T | Higher IQ (1.2µA), integrated charger, 400mA max output, 1.8mm × 1.8mm WLP - lacks forced bypass and auxiliary output. | Targets USB-charged portable devices needing battery management alongside regulation. | Choose MAX77650AWE+T when battery charging integration is required; ISL9123II2Z-T remains superior for pure ultra-low-IQ buck-only use. |
Compared with ISL9123IITZ and MAX77650AWE+T, the ISL9123II2Z-T uniquely balances I²C-programmable 2.1V output, 950nA IQ, forced bypass, and auxiliary switching in the smallest WLCSP footprint-making it optimal for firmware-adaptive, space-constrained, battery-critical systems.
Availability
ISL9123II2Z-T is available at Aetrix Electronics and suitable for smart wearables, wireless audio, and IoT edge sensors requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for ISL9123II2Z-T 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
Renesas Electronics is a global semiconductor leader specializing in microcontrollers, analog power, and timing solutions for automotive, industrial, and consumer markets.
The ISL9123 family is engineered for ultra-low-power portable electronics, delivering high efficiency at microamp loads while maintaining precision regulation and minimal footprint for next-generation wearables and sensors.
FAQ
What is the default output voltage of the ISL9123II2Z-T at power-on reset?
The ISL9123II2Z-T is factory-configured for a default output voltage of 2.1V at power-on reset (POR), as indicated by the "II2" suffix in the part number. This value is stored in OTP memory and can be reprogrammed via I²C after startup using the VSET register. The ±2.5% accuracy specification applies to this 2.1V setting under forced PWM conditions with no load.
Does the ISL9123II2Z-T support forced bypass mode, and what is its quiescent current in that state?
Yes, the ISL9123II2Z-T supports forced bypass mode, accessible exclusively via I²C register write (FMODE bits in CONV_CFG). In this mode, the internal switches conduct directly, bypassing regulation, achieving a typical quiescent current of 140nA - critical for noise-sensitive analog sections or zero-load standby states in hearing aids and medical sensors.
What package type and dimensions does the ISL9123II2Z-T use, and how many bumps does it have?
The ISL9123II2Z-T uses an 8-bump Wafer-Level Chip-Scale Package (WLCSP) measuring 1.8mm × 1.0mm with 0.4mm pitch. This ultra-compact package enables placement in tight spaces such as earbud stems and wristband modules, and its bump layout matches the standard ISL9123/A pinout defined in the datasheet (FN8959 Rev. 3.03, Page 5).
Can the ISL9123II2Z-T drive a 600mA load across its full input voltage range?
The ISL9123II2Z-T delivers up to 600mA output current only when VIN exceeds 2.5V, per the Recommended Operating Conditions table (Page 6). At lower inputs (1.8V–2.5V), peak current limit scales linearly with VIN (e.g., ~1.12A at 2.0V), but practical output current is constrained by thermal limits and efficiency drop - design validation is required for sustained 600mA below 2.5V.
How does the ISL9123II2Z-T handle overcurrent events, and what protection modes are available?
The ISL9123II2Z-T provides overcurrent protection via inductor current sensing and supports three configurable fault responses via the OC_FAULT_MODE bits: hiccup mode (100ms shutdown/retry cycle), shutdown mode (latched off until EN/VIN reset), or current-limit mode (constant peak current with drooping VOUT). These are managed through the INTFLG_MASK register and do not require external circuitry.
ISL9123II2Z-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 8-UFBGA, WLCSP
- 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):
- 0.4V
- Voltage - Output (Max):
- 5.375V
- Current - Output:
- 600mA
- Frequency - Switching:
- 2.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WLCSP (1.8x1)
ISL9123II2Z-T FAQ
1.How can I place an order for ISL9123II2Z-T through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL9123II2Z-T 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 ISL9123II2Z-T reliable?
The price and inventory of ISL9123II2Z-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL9123II2Z-T is usually 5 days.
3.What payment methods are accepted for ISL9123II2Z-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL9123II2Z-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL9123II2Z-T?
ISL9123II2Z-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL9123II2Z-T 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 ISL9123II2Z-T?
For technical support, including ISL9123II2Z-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL9123II2Z-T requirements.
6.How does Aetrix verify that ISL9123II2Z-T is sourced from the original manufacturer or authorized distributors?
All ISL9123II2Z-T 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 ISL9123II2Z-T meets industry standards.
7.What is the process for return or replacement of ISL9123II2Z-T?
All ISL9123II2Z-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL9123II2Z-T, 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 ISL9123II2Z-T part is unused and in its original packaging.
Return procedure for ISL9123II2Z-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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