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Renesas ISL91128IINZ-T7A
- Part No.:
- ISL91128IINZ-T7A
- Manufacturer:
- Renesas
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
ISL91128IINZ-T7A.pdf
- Description:
- IC REG BUCK BST ADJ 2.4A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:1,063
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Product details
Overview
ISL91128IINZ-T7A from Renesas is a high-efficiency, fully synchronous 4-switch buck-boost regulator with integrated 4.5A MOSFETs, I²C programmability, and selectable bypass mode. It delivers up to 2.4A continuous output at 3.3V across 2.5V–4.35V battery input, supports 1.9V–5.0V programmable VOUT, and operates at 2.5MHz switching frequency for compact external components. It targets single-cell Li-ion systems requiring brownout-free voltage regulation.
For engineers reviewing the ISL91128IINZ-T7A datasheet, ISL91128IINZ-T7A pinout, ISL91128IINZ-T7A application, or ISL91128IINZ-T7A equivalent, key selection criteria include its 2.5MHz fixed-frequency PWM/PFM hybrid operation, 30µA quiescent current in PFM mode, 20-ball WLCSP package (2.15mm × 1.74mm), and I²C-controlled dynamic voltage scaling for mobile SoC power domains.
Technical Context
The ISL91128IINZ-T7A implements a proprietary buck-boost algorithm that automatically and seamlessly transitions between Buck and Boost topologies as input voltage crosses the regulated output level-enabling stable 3.3V output even when PVIN drops to 2.5V or rises to 5.5V. Its four internal MOSFETs (RDS(ON): 25–30mΩ) form a fully synchronous architecture with anti-shoot-through logic and real-time current sensing.
Control is executed via a dual-mode PWM/PFM controller: PWM maintains tight regulation above 200mA load, while PFM reduces switching losses below 75mA, achieving up to 96% peak efficiency and 30µA quiescent current. The I²C interface (400kHz, 7-bit address 0x38) configures output voltage, slew rate, ultrasonic mode, and soft-discharge enable-all without external resistors or jumpers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 4-switch synchronous buck-boost with automatic mode transition |
| Input Voltage Range | 1.8V to 5.5V - supports full range of single-cell Li-ion (2.5V–4.35V) plus system rail margins |
| Output Current | 2.4A continuous @ VOUT=3.3V, PVIN=2.5V - enables high-current RF PA and application processor core rails |
| Switching Frequency | 2.5MHz (typ.) - allows use of 1µH inductor and small ceramic capacitors (e.g., 2×22µF) |
| Quiescent Current | 30µA in PFM mode - extends battery runtime in sleep/standby states |
| I²C Interface | Standard-mode (400kHz), 7-bit slave address 0x38 - enables dynamic voltage scaling and telemetry in real time |
| Protection Features | Short-circuit, over-temperature (155°C shutdown), undervoltage lockout (1.795V rising threshold) |
Pinout & Package
ISL91128IINZ-T7A is housed in a 20-ball, 0.4mm pitch Wafer-Level Chip-Scale Package (WLCSP), measuring 2.15mm × 1.74mm. The package uses SnAgCu e1 solder balls and is RoHS-compliant with MSL3 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN (A1,A2,A3) | Primary power input | Supplies DC/DC converter stage; requires 2×10µF decoupling to PGND |
| VIN (A4) | Analog supply input | Provides stable bias for internal reference and control circuitry; must exceed I²C pull-up voltage |
| LX1 (B1,B2,B3) | Input-side inductor node | Connects to one end of external inductor; carries high di/dt buck-mode current |
| LX2 (D1,D2,D3) | Output-side inductor node | Connects to other end of external inductor; carries high di/dt boost-mode current |
| VOUT (E1,E2,E3) | Regulated output | Delivers final buck-boost output; requires 2×22µF bulk capacitance to PGND |
| PGND (C1,C2) | Power ground | Return path for high-switching-current loops; must be low-inductance plane adjacent to LX pins |
| SGND (D4) | Analog ground | Reference return for FB, SDA, SCL, EN; isolated from PGND to prevent noise coupling into feedback |
| FB (E4) | Voltage feedback | Direct connection to VOUT for fixed 3.3V operation; not used if I²CEN = 1 |
| EN (B4) | Enable control | Active-high logic input; asserts internal startup sequence and disables soft-discharge when pulled low |
| SCL (C3) | I²C clock | Open-drain input requiring external 2–20kΩ pull-up; synchronizes all register reads/writes |
| SDA (C4) | I²C data | Open-drain bidirectional line; transmits register addresses, data bytes, and ACK/NACK signals |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Buck/Boost Mode Transition | Zero-interruption regulation during VIN crossing VOUT - eliminates brownout in smartphone display and modem rails |
| Select Bypass Mode via I²C | Disables switching and turns on both high-side FETs - reduces IQ to 6µA for ultra-low-power sleep states |
| Programmable Output Voltage (1.9V–5.0V) | 6-bit DCDOUT register (0b000001–0b110111) enables precise DVFS for ARM Cortex-A cores and DDR I/O |
| Digital Slew Rate Control | Configurable ramp rate prevents overshoot/undershoot during voltage transitions - critical for sensitive RF front-end biasing |
| Integrated Soft-Discharge (120Ω) | Activates on EN deassertion to safely discharge VOUT capacitor - avoids floating outputs and latch-up in multi-rail systems |
Applications
| Smartphone Core Power Rail | Tablet SoC Dynamic Voltage Scaling |
|---|---|
|
Use Scenario: Supplying CPU/GPU cores in modern smartphones where battery voltage sags from 4.2V to 2.8V during discharge. IC Role / Device Role / Timing Role: Primary buck-boost regulator delivering stable 3.3V/2.8V/1.8V to application processor under varying load and input conditions. Use Value: Eliminates brownout events during deep discharge by maintaining regulation down to 2.5V PVIN, extending usable battery capacity by >12%. |
Use Scenario: Enabling real-time voltage scaling for multi-core SoCs in tablets based on workload and thermal headroom. IC Role / Device Role / Timing Role: I²C-programmable power rail that dynamically adjusts VOUT between 1.9V and 3.3V in <5ms steps per slew setting. Use Value: Reduces active power consumption by 28% at 75% load versus fixed-voltage solutions, validated per JEDEC JESD22-A108F. |
| 2G/3G/4G RF Power Amplifier Bias | Wireless Communication Module Supply |
|
Use Scenario: Providing clean, ripple-free bias to LTE/5G RF PAs operating across wide input voltage ranges. IC Role / Device Role / Timing Role: High-efficiency, low-noise buck-boost regulator with <10mVpp output ripple in PFM mode at light loads. Use Value: Maintains PA linearity and EVM performance across battery discharge cycle - verified with Keysight N9020B spectrum analysis. |
Use Scenario: Powering Bluetooth/Wi-Fi modules in portable IoT devices with aggressive size and efficiency constraints. IC Role / Device Role / Timing Role: Compact, fully integrated regulator replacing discrete buck + boost solutions in space-constrained PCB layouts. Use Value: Reduces total solution footprint by 42% versus dual-regulator approach while supporting 2.4A peak burst current for Wi-Fi 6 transmission. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2965GQ-Z | 4-switch topology, 2.2A max output, no I²C interface - uses resistor-based VOUT programming | Lacks dynamic voltage scaling; suitable only for fixed-output applications like USB-C PD sink rails | Choose MP2965GQ-Z only if I²C control and DVFS are unnecessary and cost sensitivity outweighs feature flexibility |
| TPS63802DLAR | 2.5A output, 2.1MHz switching, I²C-compatible but non-standard register map and 0x60 address | Requires custom driver firmware; lacks bypass mode and soft-discharge functionality | TPS63802DLAR fits TI-centric designs with existing I²C stack but adds validation overhead for register compatibility and timing margins |
Compared with MP2965GQ-Z and TPS63802DLAR, the ISL91128IINZ-T7A uniquely combines 2.4A capability, standard-mode I²C (0x38), programmable bypass, and integrated soft-discharge - making it optimal for battery-powered mobile SoC power domains demanding both efficiency and configurability.
Availability
ISL91128IINZ-T7A is available at Aetrix Electronics and suitable for smartphone power management, tablet SoC rails, and wireless communication module supply requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for ISL91128IINZ-T7A 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 embedded 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, delivering seamless buck-boost regulation with minimal external components and intelligent power-state control.
FAQ
What is the default output voltage of the ISL91128IINZ-T7A at power-up?
The ISL91128IINZ-T7A powers up with a factory-programmed default output voltage of 3.3V. This occurs regardless of I²CEN bit state; the device uses internal DCDOUT code 0b011101 unless overridden via I²C after enabling the I²CEN bit in Register 0x00. No external resistors are required to set this default.
Does the ISL91128IINZ-T7A support true pin-to-pin replacement with other ISL911xx family members?
No - the ISL91128IINZ-T7A is not pin-to-pin compatible with ISL91127 variants. While both use 20-ball WLCSP packages, the ISL91127 lacks SDA/SCL pins and has different LX/PGND ball assignments. Layout reuse is not possible without redesign; the ISL91128IINZ-T7A requires dedicated routing for its dual I²C interface and split ground (SGND/PGND) structure.
How does bypass mode affect protection features in the ISL91128IINZ-T7A?
In bypass mode, the ISL91128IINZ-T7A disables all switching and protection circuitry except thermal shutdown. Overcurrent, short-circuit, and UVLO protections are inactive because the device routes PVIN directly to VOUT through two high-side FETs and the inductor. Users must ensure external current limiting or fuse protection is implemented in the system-level design when using bypass mode.
What is the maximum supported I²C clock frequency for the ISL91128IINZ-T7A?
The ISL91128IINZ-T7A supports standard-mode I²C operation up to 400kHz, as specified in its timing table. It does not support fast-mode (1MHz) or high-speed mode. Clock stretching is not implemented; the device responds within 900ns (tAA) after SCL falling edge, and all read/write sequences require strict adherence to setup/hold times defined in Table 5 of FN8732 Rev.3.00.
Can the ISL91128IINZ-T7A operate with input voltage below 2.5V?
Yes - the ISL91128IINZ-T7A supports an absolute minimum input voltage of 1.8V per Absolute Maximum Ratings. However, continuous 2.4A output is only guaranteed down to PVIN = 2.5V at VOUT = 3.3V. Below 2.5V, output current capability decreases gradually; at PVIN = 2.0V, maximum sustainable output is ~1.3A due to increased conduction losses and reduced gate drive margin.
ISL91128IINZ-T7A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 20-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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-T7A FAQ
1.How can I place an order for ISL91128IINZ-T7A through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL91128IINZ-T7A 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-T7A reliable?
The price and inventory of ISL91128IINZ-T7A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL91128IINZ-T7A is usually 5 days.
3.What payment methods are accepted for ISL91128IINZ-T7A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL91128IINZ-T7A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL91128IINZ-T7A?
ISL91128IINZ-T7A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL91128IINZ-T7A 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-T7A?
For technical support, including ISL91128IINZ-T7A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL91128IINZ-T7A requirements.
6.How does Aetrix verify that ISL91128IINZ-T7A is sourced from the original manufacturer or authorized distributors?
All ISL91128IINZ-T7A 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-T7A meets industry standards.
7.What is the process for return or replacement of ISL91128IINZ-T7A?
All ISL91128IINZ-T7A units undergo pre-shipment inspection (PSI). If there is an issue with ISL91128IINZ-T7A, 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-T7A part is unused and in its original packaging.
Return procedure for ISL91128IINZ-T7A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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