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Renesas ISL91108IIAZ-T7A
- Part No.:
- ISL91108IIAZ-T7A
- Manufacturer:
- Renesas
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
ISL91108IIAZ-T7A.pdf
- Description:
- IC REG BUCK BST ADJ 3.7A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:3,953
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Product details
Overview
ISL91108IIAZ-T7A from Intersil is a fully synchronous 4-switch buck-boost DC/DC regulator delivering up to 1.6A DC output current (PVIN = 2.8V, VOUT = 3.3V), supporting input range 1.8V–5.5V and adjustable output from 1.0V to 5.2V via external resistor divider. It features automatic seamless buck/boost mode transition, 2.6MHz switching frequency, and 27.5µA quiescent current for mobile power management in space-constrained applications.
For engineers reviewing the ISL91108IIAZ-T7A datasheet, ISL91108IIAZ-T7A pinout, ISL91108IIAZ-T7A application, or ISL91108IIAZ-T7A equivalent, key selection criteria include its WLCSP-20 package footprint, FB pin voltage regulation at 0.80V ±1.2%, PFM/PWM load-threshold hysteresis (75mA/200mA), and thermal shutdown at 150°C with 35°C hysteresis - all critical for battery-powered portable designs requiring high light-load efficiency and dynamic VIN-to-VOUT tracking.
Technical Context
The ISL91108IIAZ-T7A implements a true 4-switch buck-boost topology with independent gate drivers and anti-shoot-through logic, enabling continuous conduction mode operation across input voltages both above and below the regulated output. Its error amplifier compares FB voltage against an internal 0.80V reference, while the PWM controller dynamically selects buck or boost phase based on real-time LX1/LX2 voltage relationships and load demand.
Operation includes programmable PFM/PWM mode selection via MODE/SYNC pin, external clock synchronization (2.75–3.25MHz), soft-start ramp control (1–2ms buck, 2–3ms boost), and integrated protection including short-circuit detection via FB under-voltage, undervoltage lockout (1.725V rising threshold), and thermal shutdown with auto-recovery at +115°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.8V to 5.5V - supports single-cell Li-ion, Li-polymer, and multi-cell alkaline/NiMH inputs without pre-regulation. |
| Output Voltage Range | 1.0V to 5.2V - set by external resistor divider; enables flexible rail generation for SoCs, RF PA, and PMIC subsystems. |
| DC Output Current | 1.6A - sustained delivery at PVIN = 2.8V, VOUT = 3.3V; sufficient for baseband processors and modem power domains. |
| Burst Current Capability | 2.7A (tON <600µs) - handles transient loads from cellular transmit bursts without output collapse. |
| Switching Frequency | 2.6MHz (typ) - allows use of compact 1µH inductors and minimizes EMI filter size in RF-sensitive layouts. |
| Quiescent Current | 27.5µA - maintains >85% efficiency at 100µA load, extending battery runtime in standby/sleep states. |
| FB Reference Voltage | 0.80V ±1.2% - defines output accuracy for adjustable configurations; enables ±2% VOUT tolerance with standard 1% resistors. |
Pinout & Package
ISL91108IIAZ-T7A uses a 2.34mm × 1.72mm, 20-bump Wafer-Level Chip-Scale Package (WLCSP) with 0.4mm pitch and Pb-free e3 termination. The package exposes a thermal pad on the underside for direct PCB copper thermal coupling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A5, B5, C5 | VOUT | Main regulated output node; requires 2×22µF ceramic capacitors to PGND for low-impedance ripple suppression. |
| A4, B4, C4 | LX2 | Boost-side switch node; connects to output side of inductor; carries high di/dt during boost transitions. |
| A3, B3, C3 | PGND | Power ground return for high-current LX1/LX2 switching paths; must be low-inductance plane adjacent to IC. |
| A2, B2, C2 | LX1 | Buck-side switch node; connects to input side of inductor; carries high di/dt during buck transitions. |
| A1, B1, C1 | PVIN | Main power input for DC/DC converter stage; accepts 1.8V–5.5V; requires 2×10µF ceramic decoupling to PGND. |
| D1 | VIN | Analog supply for internal reference and control circuitry; separate from PVIN to improve PSRR and stability. |
| D2 | EN | Active-high enable; drives HIGH to initiate soft-start; pulls LOW to activate 110Ω internal VOUT discharge path. |
| D3 | MODE/SYNC | Configures PFM (HIGH) or forced PWM (LOW); also accepts 2.75–3.25MHz external sync clock for EMI reduction. |
| D4 | GND | Analog ground reference for error amp, reference, and logic; must be isolated from PGND except at single-point star connection. |
| D5 | FB | Feedback input for adjustable output; monitors divided VOUT; 0.2µA bias current enables high-value resistor networks. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Buck-Boost Mode Transition | Seamless switching between buck and boost without output voltage disturbance or control-loop instability during VIN crossing VOUT. |
| 4-Switch Synchronous Architecture | Eliminates external diodes; achieves up to 95% peak efficiency and reduces thermal stress versus 2-switch or flyback alternatives. |
| Integrated Protection Suite | Short-circuit detection via FB monitoring, thermal shutdown with hysteresis, UVLO (1.725V rising), and anti-shoot-through logic prevent latch-up and device failure. |
| Low-Noise Operation Options | Selectable forced PWM or external clock synchronization enables deterministic switching frequency for EMI filtering and coexistence with RF receivers. |
| Ultra-Small Power Solution | 2.34mm × 1.72mm WLCSP + single 1µH inductor + minimal ceramics yields <15mm² total solution area for smartphone camera modules or wearable sensors. |
Applications
| Smartphone Baseband Power | Cellular RF Power Amplifier |
|---|---|
Use Scenario: Supplying 3.3V or 4.2V to LTE/WCDMA transceiver ICs during high-power transmit bursts with rapidly varying battery voltage (3.0–4.4V). IC Role / Device Role / Timing Role: Primary buck-boost regulator providing stable output despite battery sag and VIN crossing VOUT during discharge cycles. Use Value: Delivers 2.7A burst current with <10mV output droop, maintaining PA linearity and ACLR compliance without external LDO post-regulation. | Use Scenario: Generating 3.6V for 2G/3G/4G power amplifiers from declining single-cell Li-ion (3.6–2.8V). IC Role / Device Role / Timing Role: Adaptive voltage source that switches from buck to boost as battery drops below target rail, eliminating need for dual-rail PMIC. Use Value: Maintains PA efficiency >45% across full battery range using only one inductor and no external MOSFETs or diodes. |
| Wearable Sensor Hub | IoT Edge Node MCU Core Rail |
Use Scenario: Powering ultra-low-power sensor fusion hubs (e.g., accelerometer + gyro + BLE SoC) from coin-cell or thin-film battery (2.0–3.3V). IC Role / Device Role / Timing Role: High-efficiency DC/DC converter operating in PFM mode at microamp loads, transitioning to PWM only during active sensing bursts. Use Value: 27.5µA quiescent current extends 100mAh coin-cell life to >1 year in sleep mode while supporting 1.6A peak for motion-triggered data upload. | Use Scenario: Providing 1.8V or 3.3V core voltage to ARM Cortex-M microcontrollers in battery-backed industrial telemetry nodes. IC Role / Device Role / Timing Role: Primary system regulator handling wide-input (2.2–5.5V) from energy harvesters or backup batteries while maintaining tight output regulation. Use Value: ±2% output accuracy and 0.005mV/mA load regulation ensure reliable MCU clocking and ADC reference stability across temperature and load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS63020DSJR | Fixed 3.3V output only; no adjustable version; 2.5MHz switching; 95% peak efficiency; 25µA IQ. | Requires redesign for non-3.3V outputs; lacks external sync capability; smaller 2.0mm × 1.7mm QFN package. | Choose when fixed 3.3V output suffices and board space is more constrained than flexibility. |
| MAX77827BEWL+T | Supports 1.0V–5.2V adjustable output; 2.2MHz switching; 94% peak efficiency; 22µA IQ; I²C programmable. | Requires I²C interface and firmware support; larger 2.1mm × 1.6mm WLP; no external sync pin. | Choose when digital configurability (voltage, slew rate, fault response) justifies added software complexity. |
Compared with TPS63020DSJR and MAX77827BEWL+T, the ISL91108IIAZ-T7A uniquely combines adjustable output, external clock synchronization, and seamless buck-boost transition in a 2.34mm × 1.72mm WLCSP - making it optimal for RF-critical, battery-voltage-tracking applications where analog control simplicity and minimal footprint are mandatory.
Availability
ISL91108IIAZ-T7A is available at Aetrix Electronics and suitable for smartphone baseband power, cellular RF power amplifier supplies, and wearable sensor hub designs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for ISL91108IIAZ-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
Intersil Corporation is a leading provider of precision analog and power management ICs, now part of Renesas Electronics, with deep expertise in high-efficiency DC/DC conversion and mobile power solutions.
The ISL91108 product line was designed specifically for space-constrained portable electronics requiring wide-input, adjustable-output buck-boost regulation with minimal external components and best-in-class light-load efficiency.
FAQ
What is the recommended inductor value and saturation current rating for ISL91108IIAZ-T7A?
The ISL91108IIAZ-T7A datasheet specifies a 1µH inductor with ≥4.0A saturation current rating. This ensures safe operation under 2.7A burst conditions without core saturation or efficiency loss. Ferrite-core shielded or toroidal inductors are preferred to minimize radiated EMI in RF-dense layouts. Recommended part series include Toko 1277AS-H-1R0M and Coilcraft XFL4020-102ME.
How does the MODE/SYNC pin function in ISL91108IIAZ-T7A?
In ISL91108IIAZ-T7A, the MODE/SYNC pin serves dual functions: pulled HIGH enables automatic PFM mode for light-load efficiency, pulled LOW forces continuous PWM operation for noise-sensitive applications, and driven with a 2.75–3.25MHz external clock synchronizes switching to reduce beat frequencies and simplify EMI filtering. The pin accepts standard logic levels and has 0.03–0.5µA leakage current.
What is the purpose of the separate VIN and PVIN pins on ISL91108IIAZ-T7A?
The ISL91108IIAZ-T7A uses separate VIN and PVIN pins to isolate the analog reference and control circuitry (powered by VIN) from high-current switching paths (fed by PVIN). This separation improves PSRR, reduces noise coupling into the error amplifier, and enhances output voltage accuracy and stability - especially critical when powering noise-sensitive RF or precision analog circuits from the same battery source.
Can ISL91108IIAZ-T7A operate with input voltage equal to output voltage?
Yes, ISL91108IIAZ-T7A is explicitly designed to operate with input voltage close to or equal to output voltage. Its 4-switch architecture enables rapid, seamless transitions between buck and boost modes, maintaining regulation with minimal output ripple and no control-loop disruption - unlike traditional buck-boost converters that exhibit discontinuity or instability at VIN ≈ VOUT.
What is the soft-discharge behavior of ISL91108IIAZ-T7A when EN is pulled low?
When EN is pulled low on ISL91108IIAZ-T7A, an internal 110Ω resistor connects VOUT to GND, discharging the output capacitor safely and predictably. This prevents floating outputs and unintended wake-up of downstream circuitry. The discharge time depends on output capacitance and load but is typically under 10ms for 44µF total COUT - ensuring clean power-down sequencing in battery-powered systems.
ISL91108IIAZ-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):
- 1V
- Voltage - Output (Max):
- 5.2V
- Current - Output:
- 3.7A (Switch)
- Frequency - Switching:
- 2.6MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-WLCSP
ISL91108IIAZ-T7A FAQ
1.How can I place an order for ISL91108IIAZ-T7A through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL91108IIAZ-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 ISL91108IIAZ-T7A reliable?
The price and inventory of ISL91108IIAZ-T7A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL91108IIAZ-T7A is usually 5 days.
3.What payment methods are accepted for ISL91108IIAZ-T7A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL91108IIAZ-T7A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL91108IIAZ-T7A?
ISL91108IIAZ-T7A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL91108IIAZ-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 ISL91108IIAZ-T7A?
For technical support, including ISL91108IIAZ-T7A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL91108IIAZ-T7A requirements.
6.How does Aetrix verify that ISL91108IIAZ-T7A is sourced from the original manufacturer or authorized distributors?
All ISL91108IIAZ-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 ISL91108IIAZ-T7A meets industry standards.
7.What is the process for return or replacement of ISL91108IIAZ-T7A?
All ISL91108IIAZ-T7A units undergo pre-shipment inspection (PSI). If there is an issue with ISL91108IIAZ-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 ISL91108IIAZ-T7A part is unused and in its original packaging.
Return procedure for ISL91108IIAZ-T7A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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