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Renesas ISL91128IINZ-T
- Part No.:
- ISL91128IINZ-T
- Manufacturer:
- Renesas
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
ISL91128IINZ-T.pdf
- Description:
- IC REG BUCK BST ADJ 2.4A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:1,455
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Product details
Overview
ISL91128IINZ-T from Renesas is a high-efficiency, fully synchronous 4-switch buck-boost regulator with I²C interface, delivering up to 2.4A continuous output current (VOUT = 3.3V, VIN = 2.5V), 2.5MHz switching frequency, and programmable output voltage from 1.9V to 5.0V. It maintains regulation across input voltages from 1.8V to 5.5V and enables brownout-free power for single-cell Li-ion battery systems in smartphones and RF power amplifiers.
For engineers reviewing the ISL91128IINZ-T datasheet, ISL91128IINZ-T pinout, ISL91128IINZ-T application, or ISL91128IINZ-T equivalent, key selection considerations include its seamless buck/boost mode transition, 30µA quiescent current in PFM mode, selectable bypass mode for ultra-low-power sleep states, and integrated short-circuit/thermal protection.
Technical Context
The ISL91128IINZ-T implements a proprietary buck-boost algorithm that dynamically selects between Buck and Boost topologies based on real-time comparison of PVIN and VOUT, enabling stable regulation when input voltage crosses the output setpoint. Its 4-switch synchronous architecture uses internal N- and P-channel MOSFETs with RDS(ON) as low as 25mΩ (N-ch) and 27mΩ (P-ch).
Control is executed via a PWM/PFM hybrid scheme: PFM dominates at light loads (<75mA) for ultra-low IQ, while PWM engages above 200mA for tight regulation and low ripple. The I²C interface (400kHz, standard-mode) provides full access to output voltage programming, slew rate control, ultrasonic mode enable, and soft-discharge configuration - all without requiring external resistors or components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 2.4A continuous (at VOUT = 3.3V, PVIN = 2.5V); supports full load across 2.5–4.35V battery range. |
| Input Voltage Range | 1.8V to 5.5V; accepts inputs both above and below regulated VOUT, enabling single-supply operation from aging Li-ion cells. |
| Switching Frequency | 2.5MHz (typical); minimizes external inductor size (1µH typical) and capacitor footprint (2×22µF output). |
| Quiescent Current | 30µA in PFM mode; extends battery runtime in always-on or low-duty-cycle applications like sensor hubs. |
| Output Voltage Range | 1.9V to 5.0V, digitally programmable via I²C; factory default is 3.3V (per ordering code IINZ-T). |
| Protection Features | Integrated short-circuit, over-temperature (155°C shutdown), and undervoltage lockout (1.725V rising threshold). |
| Efficiency | Up to 96% at mid-load (e.g., 500mA, VIN = 3.6V → VOUT = 3.3V); optimized by low-RDS(ON) switches and adaptive mode control. |
Pinout & Package
ISL91128IINZ-T is housed in a 20-ball, 0.4mm pitch Wafer-Level Chip-Scale Package (WLCSP), measuring 2.15mm × 1.74mm. The package features dual ground domains (PGND for power switching, SGND for analog reference) and bump layout optimized for minimal loop inductance in high-frequency buck-boost operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN (A1,A2,A3) | Primary power input | Supplies DC/DC converter stage; requires 2×10µF ceramic capacitors to PGND for high di/dt stability. |
| VIN (A4) | Analog supply input | Provides clean bias for internal reference and control logic; must be ≥ I²C pull-up voltage. |
| EN (B4) | Enable control input | Active-HIGH logic; asserts internal startup sequence and disables soft-discharge when pulled low. |
| LX1 (B1,B2,B3) | High-side inductor node (buck input / boost output) | Connects to one end of external inductor; carries high-frequency AC current in both buck and boost phases. |
| LX2 (D1,D2,D3) | Low-side inductor node (buck output / boost input) | Connects to opposite inductor end; switching node shared between buck and boost topologies. |
| VOUT (E1,E2,E3) | Regulated output | Delivers final system voltage; connects to 2×22µF bulk capacitance and downstream loads. |
| FB (E4) | Feedback sense | Direct connection to VOUT for fixed-output variants; not used in ISL91128IINZ-T (factory-programmed 3.3V). |
| SDA / SCL (C4 / C3) | I²C data/clock | Open-drain pins requiring external 2–20kΩ pull-ups; support standard-mode (400kHz) communication only. |
| PGND (C1,C2) | Power ground | Return path for high-current LX switching; must be solidly connected to input/output capacitors' ground pads. |
| SGND (D4) | Analog ground | Reference for FB, EN, and I²C interface; isolated from PGND to prevent noise coupling into regulation loop. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic buck/boost mode transition | Seamless topology switching at VIN ≈ VOUT eliminates output glitches and reduces voltage ripple during battery discharge. |
| Selectably enabled bypass mode | Direct conduction path through two high-side FETs reduces quiescent current to 6.0µA, ideal for system sleep states. |
| Digital output voltage slew rate control | Programmable ramp rate prevents overshoot/undershoot during dynamic voltage scaling in multi-core SoCs. |
| Integrated soft-start and soft-discharge | 2ms typical soft-start (buck), 3ms (boost); 120Ω internal discharge resistor prevents unsafe VOUT hold-up after disable. |
| Full protection suite | Short-circuit foldback, thermal shutdown with 30°C hysteresis, and UVLO ensure robust operation in portable environments. |
Applications
| Smartphone Baseband Power | RF Power Amplifier Bias |
|---|---|
|
Use Scenario: Powers application processor cores and memory subsystems during deep discharge (2.5V–3.6V battery range) while maintaining 3.3V system rail. IC Role / Device Role / Timing Role: Primary system buck-boost regulator providing uninterrupted VDD_IO and VDD_MMC rails. Use Value: Eliminates brownouts during LTE transmission bursts by sustaining regulation even as battery voltage drops below nominal VOUT. |
Use Scenario: Supplies dynamically scaled voltage to 2G/3G/4G PA modules requiring 3.0–4.2V under varying RF output power. IC Role / Device Role / Timing Role: Programmable PA bias controller with I²C-adjustable VOUT and fast transient response. Use Value: Enables envelope tracking-like efficiency gains via real-time VOUT adjustment synchronized to PA gain state. |
| Tablet PC System-on-Chip Supply | Wireless IoT Sensor Hub |
|
Use Scenario: Delivers 3.3V core power to ARM-based SoC in tablet designs where battery voltage spans 3.0–4.35V. IC Role / Device Role / Timing Role: Main SoC PMIC buck-boost channel with integrated sequencing and protection. Use Value: Reduces BOM count by replacing discrete buck + boost stages and external enable logic. |
Use Scenario: Powers BLE/Wi-Fi MCU and sensors in compact battery-powered nodes operating 24/7 on coin cells or small Li-ion. IC Role / Device Role / Timing Role: Ultra-low-IQ power source supporting periodic wake-up, sensing, and transmit cycles. Use Value: Extends operational lifetime by 3.5× vs. traditional LDOs due to 30µA PFM IQ and 96% peak efficiency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2964GQ-Z | 4-switch buck-boost with PMBus interface; 2.2MHz fSW; 3.5A max output; no bypass mode. | Targets server VRMs and industrial PoL; lacks low-power sleep optimization for portable devices. | Choose MP2964GQ-Z if PMBus telemetry and higher current are required, but avoid for battery-life-critical mobile apps. |
| TPS63802DLAR | I²C-programmable buck-boost; 2.4A output; 2.1MHz fSW; 18µA IQ; no soft-discharge or ultrasonic mode. | Focused on wearables and hearables; smaller 1.67mm × 1.67mm WLCSP but limited voltage range (2.3–5.5V). | Choose TPS63802DLAR for space-constrained ultra-low-power designs where 3.3V fixed output suffices and soft-discharge is noncritical. |
Compared with MP2964GQ-Z and TPS63802DLAR, the ISL91128IINZ-T uniquely combines 30µA quiescent current, integrated soft-discharge, bypass mode, and 1.9–5.0V programmability in a production-qualified mobile-optimized WLCSP - making it the preferred choice for smartphone and tablet main rail applications demanding battery longevity and glitch-free voltage transitions.
Availability
ISL91128IINZ-T is available at Aetrix Electronics and suitable for smartphone baseband power, RF power amplifier bias, and tablet SoC supply applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL91128IINZ-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 management, and timing solutions for automotive, industrial, and consumer markets.
The ISL91128 product line was designed specifically for advanced single-cell Li-ion battery systems in mobile computing and wireless infrastructure, emphasizing efficiency across wide Vin-to-Vout differentials and seamless dynamic voltage scaling.
FAQ
What is the default output voltage of the ISL91128IINZ-T?
The ISL91128IINZ-T is factory-programmed to deliver a fixed 3.3V output voltage, as indicated by the "IINZ" ordering suffix. No external feedback resistors are required, and the FB pin is internally connected. This simplifies design for applications where 3.3V is the target system rail, such as baseband processors and peripheral interfaces.
Does the ISL91128IINZ-T support true I²C-compatible communication?
Yes, the ISL91128IINZ-T implements a standard-mode I²C slave interface compliant with JEDEC specifications: SDA/SCL pins are open-drain, support 400kHz clock rates, and respond to the 7-bit slave address 0x38 (0b0011100). It acknowledges valid START+address sequences and supports register-level read/write operations per the documented protocol - confirmed in FN8732 Rev.3.00, pages 11–14.
How does bypass mode function in the ISL91128IINZ-T?
In bypass mode, the ISL91128IINZ-T turns ON both high-side P-channel MOSFETs to create a low-resistance conduction path from PVIN to VOUT through the external inductor, disabling all switching and regulation circuitry. This reduces quiescent current to 6.0µA. Bypass mode is enabled by default at power-up and can be disabled via I²C bit D5 in the Mode Control register.
What thermal protection mechanisms does the ISL91128IINZ-T include?
The ISL91128IINZ-T incorporates thermal shutdown that activates at +155°C (typical junction temperature), halting all switching activity. Operation resumes automatically when die temperature falls to +125°C (30°C hysteresis). During shutdown, the device retains I²C register state and executes full soft-start upon recovery - ensuring safe, repeatable re-entry into regulation without external intervention.
Can the ISL91128IINZ-T operate with input voltage below 2.5V?
Yes, the ISL91128IINZ-T supports an input voltage range of 1.8V to 5.5V per Absolute Maximum Ratings and Recommended Operating Conditions. It delivers rated 2.4A output down to PVIN = 2.5V (VOUT = 3.3V), and remains functional - though at reduced current capability - as low as 1.8V, enabling full utilization of depleted Li-ion cells down to 2.0V cutoff.
ISL91128IINZ-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 20-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.9V
- Voltage - Output (Max):
- 5V
- Current - Output:
- 2.4A
- Frequency - Switching:
- 2.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-WLCSP (2.15x1.74)
ISL91128IINZ-T FAQ
1.How can I place an order for ISL91128IINZ-T through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL91128IINZ-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 ISL91128IINZ-T reliable?
The price and inventory of ISL91128IINZ-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL91128IINZ-T is usually 5 days.
3.What payment methods are accepted for ISL91128IINZ-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL91128IINZ-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL91128IINZ-T?
ISL91128IINZ-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL91128IINZ-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 ISL91128IINZ-T?
For technical support, including ISL91128IINZ-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL91128IINZ-T requirements.
6.How does Aetrix verify that ISL91128IINZ-T is sourced from the original manufacturer or authorized distributors?
All ISL91128IINZ-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 ISL91128IINZ-T meets industry standards.
7.What is the process for return or replacement of ISL91128IINZ-T?
All ISL91128IINZ-T units undergo pre-shipment inspection (PSI). If there is an issue with ISL91128IINZ-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 ISL91128IINZ-T part is unused and in its original packaging.
Return procedure for ISL91128IINZ-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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