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Renesas ISL91108IINZ-T7A
- Part No.:
- ISL91108IINZ-T7A
- Manufacturer:
- Renesas
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
ISL91108IINZ-T7A.pdf
- Description:
- IC REG BCK BST 3.3V 3.7A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:199
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Product details
Overview
ISL91108IINZ-T7A from Renesas (formerly Intersil) is a fully synchronous 4-switch buck-boost DC/DC regulator delivering up to 1.6A DC output current at 3.3V with 2.6MHz switching frequency, 27.5µA quiescent current, and automatic seamless buck/boost mode transition - designed for compact mobile power rails in smartphones and tablets.
For engineers reviewing the ISL91108IINZ-T7A datasheet, ISL91108IINZ-T7A pinout, ISL91108IINZ-T7A application, or ISL91108IINZ-T7A equivalent, key selection criteria include its fixed 3.3V output, 20-bump WLCSP package, input range of 1.8V–5.5V, burst current capability of 2.7A, and support for forced PWM or external clock synchronization in noise-sensitive RF power amplifier stages.
Technical Context
The ISL91108IINZ-T7A implements a true 4-switch buck-boost topology with integrated P- and N-channel MOSFETs (RDSON_P = 90mΩ, RDSON_N = 75mΩ), enabling continuous regulation when input voltage crosses the 3.3V output - unlike 3-switch or SEPIC alternatives. Its dual-input architecture separates PVIN (power path) from VIN (reference supply), minimizing reference disturbance during high di/dt switching.
Control logic includes auto PFM/PWM mode switching (transition thresholds at 75mA/200mA), soft-start with mode-dependent ramp timing (2ms buck / 3ms boost), and VOUT soft-discharge via internal 110Ω switch. Protection features include thermal shutdown at +150°C (35°C hysteresis), short-circuit detection via FB monitoring, and UVLO with 1.775V rising threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V - eliminates external feedback resistors and reduces BOM count and layout sensitivity. |
| Input Voltage Range | 1.8V to 5.5V - supports single-cell Li-ion (2.8–4.2V), USB VBUS (4.75–5.5V), and partially discharged batteries without rail collapse. |
| DC Output Current | 1.6A at PVIN = 2.8V, VOUT = 3.3V - sufficient for baseband processors and modem subsystems in portable devices. |
| Burst Current | 2.7A for tON <600µs, period = 4.6ms - handles transient loads from 2G/3G/4G PA turn-on without output droop. |
| Quiescent Current | 27.5µA in PFM mode - extends battery runtime during display-off or sleep states in always-on applications. |
| Switching Frequency | 2.6MHz (typ) - enables use of small 1µH inductors and low-ESR ceramic capacitors, reducing total solution size to <15mm². |
| Efficiency Peak | 95% - achieved via synchronous rectification and low-RDS(on) internal switches, minimizing conduction losses across load range. |
Pinout & Package
ISL91108IINZ-T7A uses a 2.34mm × 1.72mm, 20-bump WLCSP (W4x5.20F) with 0.4mm pitch and exposed thermal pad on underside. Package supports Pb-free reflow per J-STD-020 MSL3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A5, B5, C5 | VOUT | Regulated 3.3V output node - requires 2×22µF X5R ceramic capacitors directly to PGND for ripple suppression. |
| A4, B4, C4 | LX2 | Boost-side switch node - connects to output side of 1µH inductor; carries high-frequency AC current during boost operation. |
| A3, B3, C3 | PGND | Power ground return for LX1/LX2 switching currents - must be low-inductance plane tied to input/output capacitor grounds. |
| A2, B2, C2 | LX1 | Buck-side switch node - connects to input side of inductor; active during buck mode and PFM pulse charging. |
| A1, B1, C1 | PVIN | Main power input (1.8–5.5V) - supplies switching FETs; requires 2×10µF X5R ceramic decoupling to PGND. |
| D1 | VIN | Analog supply for internal reference and control circuitry - independent of PVIN to stabilize regulation under dynamic load. |
| D2 | EN | Active-high enable - asserts internal bias and starts soft-start sequence; pulled low disables regulator and activates 110Ω VOUT discharge path. |
| D3 | MODE/SYNC | Selects PFM (HIGH) or forced PWM (LOW); also accepts 2.75–3.25MHz external clock for EMI reduction in sensitive RF bands. |
| D4 | GND | Analog ground reference - isolated from PGND to prevent switching noise coupling into error amplifier and reference circuits. |
| D5 | FB | Feedback input - internally shorted to VOUT in IINZ variant; not used externally for fixed-output configuration. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic buck/boost mode transition | Zero-output-disturbance crossover when VIN crosses VOUT - maintains stable 3.3V rail during battery discharge from 4.2V to 2.8V. |
| 2.6MHz constant-frequency operation | Enables ultra-compact filter design: 1µH inductor + 44µF output capacitance fits within 3mm × 3mm PCB area. |
| 27.5µA quiescent current | Extends system standby time by >30% vs. comparable 100µA regulators in always-on sensor hub or RTC applications. |
| Integrated 4-switch architecture | Eliminates need for external MOSFETs or complex gate drivers - reduces component count by ≥6 parts vs. discrete buck-boost solutions. |
| VIN and PVIN separation | Prevents reference instability during high-current PVIN transients - critical for maintaining ±2% output accuracy under pulsed PA loads. |
Applications
| Smartphone Application | Tablet Power Management |
|---|---|
|
Use Scenario: Powering application processor I/O rails during dynamic DVFS transitions and cellular transmit bursts. IC Role / Device Role / Timing Role: Primary buck-boost regulator supplying fixed 3.3V to SoC interface banks and PMIC peripherals. Use Value: Seamless mode transition prevents brownout during battery voltage sag from 3.6V to 3.0V, ensuring uninterrupted data throughput. |
Use Scenario: Generating stable 3.3V for USB PHY, display interface, and audio codec in dual-battery tablet platforms. IC Role / Device Role / Timing Role: Standalone voltage regulator interfacing between variable battery stack (3.0–4.4V) and fixed-voltage subsystems. Use Value: 2.6MHz switching avoids AM radio band interference while supporting fast load-step response (<10µs) for touch controller wake events. |
| 2G/3G/4G Power Amplifier Supply | Wireless Communication Module |
|
Use Scenario: Delivering burst current to RF power amplifiers during GSM EDGE or LTE uplink transmission. IC Role / Device Role / Timing Role: High-pulse-current buck-boost stage placed between battery and PA drain supply node. Use Value: 2.7A burst capability sustains PA peak envelope power without collapsing VOUT below 3.1V, preserving ACLR performance. |
Use Scenario: Providing regulated 3.3V to Bluetooth/Wi-Fi combo modules operating across wide input voltage ranges. IC Role / Device Role / Timing Role: Single-chip DC/DC solution replacing discrete LDO + boost combinations in space-constrained IoT modules. Use Value: 95% peak efficiency and 27.5µA IQ reduce thermal load and extend coin-cell or energy-harvesting battery life by >2×. |
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, 2.5MHz switching, 2.5A DC rating, but higher 40µA IQ and no external sync capability. | Preferred where higher DC current is required, but less suitable for ultra-low-power sleep modes or EMI-critical RF co-location. | Select TPS63020DSJR if board-level EMI filtering is impractical and peak current >1.6A is mandatory. |
| MAX77827AEWP+T | Adjustable output (0.6–5.2V), 2.2MHz, 2.2A DC, includes I²C programmability and comprehensive telemetry, but larger 2.1mm × 1.6mm WLP. | Suitable for systems requiring dynamic voltage scaling or health monitoring, but over-specified for fixed 3.3V smartphone rail use. | Choose MAX77827AEWP+T only when firmware-controlled output adjustment or fault logging is required. |
Compared with TPS63020DSJR and MAX77827AEWP+T, the ISL91108IINZ-T7A offers optimal balance of ultra-low IQ, external clock synchronization, and minimal footprint for cost-sensitive, battery-powered 3.3V rails - making it preferred for volume smartphone and tablet designs where fixed output and EMI control are primary constraints.
Availability
ISL91108IINZ-T7A is available at Aetrix Electronics and suitable for smartphone power management, tablet subsystem regulation, and wireless communication device PA supply requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for ISL91108IINZ-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 Corporation (acquired Intersil in 2017) is a global leader in microcontrollers, analog, and power management ICs, serving automotive, industrial, and consumer markets with high-reliability semiconductor solutions.
The ISL91108 product line was developed specifically for high-efficiency, space-constrained mobile power conversion - targeting battery-operated devices needing seamless buck-boost regulation with minimal external components and ultra-low quiescent current.
FAQ
What is the maximum continuous output current supported by the ISL91108IINZ-T7A?
The ISL91108IINZ-T7A delivers up to 1.6A DC output current under specified conditions: PVIN = 2.8V, VOUT = 3.3V, and ambient temperature ≤+85°C. This rating assumes proper PCB thermal design using the exposed thermal pad and recommended 2×10µF input / 2×22µF output ceramic capacitors. Exceeding this current may trigger thermal shutdown or reduce regulation accuracy.
Does the ISL91108IINZ-T7A require external feedback resistors to set the output voltage?
No - the ISL91108IINZ-T7A is the fixed-output variant with factory-trimmed 3.3V regulation. Its FB pin is internally connected to VOUT, eliminating the need for external resistor dividers. This simplifies layout, improves accuracy stability against resistor tolerance drift, and reduces BOM cost versus adjustable versions like ISL91108IIAZ-T7A.
Can the ISL91108IINZ-T7A synchronize to an external clock, and what is the acceptable frequency range?
Yes - the MODE/SYNC pin (D3) accepts an external clock signal for synchronization. The ISL91108IINZ-T7A locks to input frequencies between 2.75MHz and 3.25MHz with ±2% tolerance. This feature enables EMI reduction by shifting switching noise away from sensitive RF bands such as LTE uplink or Bluetooth channels, and is enabled by pulling MODE/SYNC LOW and applying the clock signal.
What protection features are integrated into the ISL91108IINZ-T7A?
The ISL91108IINZ-T7A integrates short-circuit protection (via FB voltage monitoring), thermal shutdown (+150°C trip with +35°C hysteresis), input undervoltage lockout (1.775V rising threshold), and reverse-current blocking. It also provides soft-discharge functionality (110Ω internal path from VOUT to GND upon EN deactivation) to prevent residual voltage from interfering with system power sequencing.
How does the ISL91108IINZ-T7A handle transitions between buck and boost modes?
The ISL91108IINZ-T7A performs automatic and seamless transitions between buck and boost modes without output voltage disturbance or control-loop interruption. Its 4-switch architecture and proprietary mode-control logic ensure continuous regulation as input voltage crosses the 3.3V output level - verified in datasheet Figure 2 efficiency curves and functional description section on page 6.
ISL91108IINZ-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:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- 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
ISL91108IINZ-T7A FAQ
1.How can I place an order for ISL91108IINZ-T7A through Aetrix?
Please submit a Request for Quotation (RFQ) for ISL91108IINZ-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 ISL91108IINZ-T7A reliable?
The price and inventory of ISL91108IINZ-T7A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISL91108IINZ-T7A is usually 5 days.
3.What payment methods are accepted for ISL91108IINZ-T7A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISL91108IINZ-T7A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISL91108IINZ-T7A?
ISL91108IINZ-T7A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISL91108IINZ-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 ISL91108IINZ-T7A?
For technical support, including ISL91108IINZ-T7A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISL91108IINZ-T7A requirements.
6.How does Aetrix verify that ISL91108IINZ-T7A is sourced from the original manufacturer or authorized distributors?
All ISL91108IINZ-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 ISL91108IINZ-T7A meets industry standards.
7.What is the process for return or replacement of ISL91108IINZ-T7A?
All ISL91108IINZ-T7A units undergo pre-shipment inspection (PSI). If there is an issue with ISL91108IINZ-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 ISL91108IINZ-T7A part is unused and in its original packaging.
Return procedure for ISL91108IINZ-T7A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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