ISL9103AIRUCZ-T - 500mA 2.4MHz Sync Buck 1.8V Fixed | Renesas
MPN: ISL9103AIRUCZ-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.95 | $1.95 |
| 10 | $1.72 | $17.20 |
| 100 | $1.48 | $148.00 |
| 500 | $1.27 | $635.00 |
| 1,000 | $1.1 | $1,100.00 |
| 3,000 | $0.95 | $2,850.00 |
ISL9103AIRUCZ-T Overview
A buck switching regulator (also called a step-down converter) is a switch-mode power supply topology that converts a higher DC input voltage into a lower DC output voltage by periodically switching an inductor and rectifying the resulting waveform. Buck regulators occupy the power management IC category alongside LDOs, boost converters, and charge pumps, and are preferred over LDOs whenever input-to-output voltage differential is large because they can exceed 90% efficiency. The ISL9103A family targets low-power point-of-load rails in portable, battery-powered devices where board space is at a premium.
Key features include a typical quiescent current that supports long battery standby, 2.4 MHz PWM switching that enables a sub-1 mm profile inductor, internal synchronous rectification that eliminates the external Schottky diode, and built-in protection including overcurrent, thermal shutdown, and soft-start. The 6-pin UTDFN occupies only 1.6 x 1.6 mm of board area, making it suitable for sub-30 mm square power sections in wearables, handsets, and IoT endpoints.
The device uses a peak-current-mode PWM control architecture with internal compensation, simplifying external design and providing predictable small-signal response across line and load variation. Internal MOSFETs and synchronous rectification eliminate the need for an external Schottky, while 100% duty cycle extends usable input range when the battery droops toward the output setpoint.
Typical applications include powering low-voltage microprocessors in PDAs and cellular phones, single-cell Li+ battery rails in portable media players, and as a post-DCDC point-of-load regulator for application processors in handheld products.
A key design consideration is the 2.4 MHz switching frequency: the inductor can be small (typically 1.0 to 2.2 uH), but PCB layout must minimize the input/output loop area to limit radiated EMI from the switching node.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ISL9103AIRUCZ-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ISL9103IRUCZ-T
✅ Drop-In📋 Reference alternative (not in catalog)
ISL9104IRUCZ-T
✅ Drop-In📋 Reference alternative (not in catalog)
ISL9105IRUCZ-T
✅ Drop-In📋 Reference alternative (not in catalog)
ISL9103AIRUCZ-T Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Step-Down (Buck) |
| Input Voltage Range | 2.7 V to 6 V |
| Output Voltage | 1.8 V (fixed) |
| Maximum Output Current | 500 mA |
| Switching Frequency | 2.4 MHz (typical) |
| Dropout Voltage | less than 300 mV at 500 mA |
| Quiescent Current | Low-IQ (value in datasheet) |
| Internal MOSFETs | P-channel high-side + N-channel low-side synchronous pair |
| Duty Cycle Range | 0% to 100% (100% duty cycle operation) |
| Control Architecture | Peak current-mode PWM |
| Minimum Output Voltage | 0.8 V (family capability, this part fixed at 1.8 V) |
| Package | 6-pin UTDFN (UFDFN) 1.6 x 1.6 mm |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (per distributor listing) |
ISL9103AIRUCZ-T 6-pin utdfn (ufdfn) 1.6 x 1.6 mm Pin Configuration Guide
Pin configuration for ISL9103AIRUCZ-T (6-pin utdfn (ufdfn) 1.6 x 1.6 mm package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for ISL9103AIRUCZ-T.
Refer to the datasheet for full pin configuration.
Typical Applications
ISL9103AIRUCZ-T is suitable for 6 applications: Cellular Phone Baseband Power Rail, PDA / Handheld Processor Power, Single-Cell Li-Ion Portable Media Player, Wearable / IoT Sensor Node Power, Point-of-Load for Application Processor, Industrial Handheld Terminal.
Cellular Phone Baseband Power Rail
The ISL9103AIRUCZ-T is purpose-built for 1.8 V / 500 mA point-of-load rails inside cellular phone baseband subsystems. Its 2.4 MHz switching frequency permits a 1.0 to 2.2 uH chip inductor less than 1 mm tall, freeing PCB real estate for the RF shield and antenna. Synchronous rectification keeps efficiency above 90% at 200 to 400 mA typical baseband load, and the integrated MOSFETs remove the need for any external Schottky. Place the input cap within 2 mm of the VIN pad and route the LX node away from sensitive RF traces to avoid conducted noise coupling into the receive path.
Recommended
PDA / Handheld Processor Power
Handheld PDAs and organizer-style devices run application processors at 1.8 V core voltage drawing up to 500 mA under active load. The ISL9103AIRUCZ-T's fixed 1.8 V output and 2.4 MHz switching deliver the rail cleanly with only three external components: a 2.2 uH inductor, a 4.7 uF input cap, and a 10 uF output cap. Its less-than-300 mV dropout at 500 mA extends usable Li-ion runtime when the cell sags to 2.1 V. The 1.6 x 1.6 mm UTDFN package fits easily beside the processor BGA on the underside of the main board.
Recommended
Single-Cell Li-Ion Portable Media Player
Portable media players and MP3 players rely on a single Li-ion cell ranging from 4.2 V fully charged to 3.0 V end-of-discharge. The ISL9103AIRUCZ-T accepts this full 3.0 V to 4.2 V range and produces a stable 1.8 V at 500 mA for the audio DAC, codec, and baseband logic. Synchronous rectification keeps light-load efficiency high, important for standby runtime where the audio subsystem idles. The 6-pin UTDFN enables mounting under the battery tab without intruding into the audio path layout.
Recommended
Wearable / IoT Sensor Node Power
Battery-powered wearables and IoT sensor nodes require sub-30 mm square power sections that can sustain days or weeks of standby. The ISL9103AIRUCZ-T's low-IQ design minimizes quiescent drain, while its 1.6 x 1.6 mm UTDFN footprint and 2.4 MHz switching allow the entire converter to occupy less than 10 mm square including the inductor. Running from a 3.7 V Li-Po or two alkaline cells in series, it provides 1.8 V to a BLE radio, microcontroller, and sensor front-end. Synchronous PEX and high-side P-FET ensure clean cold-start with the load already present.
Recommended
Point-of-Load for Application Processor
After a main 3.3 V or 5 V buck, system boards often require a localized 1.8 V rail for application processor I/O or peripheral logic. The ISL9103AIRUCZ-T serves as a compact post-regulator, taking the intermediate rail and delivering clean 1.8 V at 500 mA to the SoC's GPIO bank or external flash. Its 2.4 MHz switching is offset from typical 1 MHz intermediate rails, reducing beat-frequency noise. The internal soft-start prevents inrush when the upstream rail is already energized.
Recommended
Industrial Handheld Terminal
Industrial barcode scanners, rugged PDAs, and field-service terminals need reliable 1.8 V rails across a wider temperature range than consumer handsets. The ISL9103AIRUCZ-T's synchronous buck architecture produces less heat than an LDO at the same load, improving long-term reliability in sealed enclosures. Operating from a 2.7 V to 6 V input accommodates single Li-ion packs, two- or three-cell battery boxes, and regulated 5 V USB inputs. The exposed pad on the 6-pin UTDFN provides solid thermal contact with the inner ground plane.
Recommended
Recommended Products Summary
Engineering reference data for ISL9103AIRUCZ-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ISL9103IRUCZ-T | ISL9104IRUCZ-T | ISL9105IRUCZ-T |
|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | 6-pin UTDFN 1.6x1.6 mm | 6-pin UTDFN - same | 6-pin UTDFN - same | 6-pin UTDFN - same |
| Topology | Synchronous Buck | Synchronous Buck | Synchronous Buck | Synchronous Buck |
| Input Voltage Range | 2.7 V to 6 V | 2.7 V to 6 V | 2.7 V to 6 V | 2.7 V to 6 V |
| Output Voltage | 1.8 V (fixed) | Different fixed voltage (verify suffix) | Different fixed voltage (verify suffix) | Different fixed voltage (verify suffix) |
| Internal MOSFETs | P-FET high-side + N-FET low-side synchronous | Same architecture | Same architecture | Same architecture |
Key Differentiators
- Newer-generation -A suffix optimized for low-IQ and high light-load efficiency (vs ISL9103IRUCZ-T)
- Tape-and-reel -T suffix for high-volume production lines (vs ISL9103AIRUCZ (tray version))
- Fixed 1.8 V output eliminates external feedback divider (vs ISL9104IRUCZ-T / ISL9105IRUCZ-T (different fixed voltages))
Design Notes
Place the input capacitor within 2 mm of the VIN and GND pads to minimize high-frequency loop area. Route the LX (switch node) trace on a single layer away from sensitive analog signals; avoid running LX under the IC or under feedback traces. Use a solid ground pour directly under the exposed pad of the UTDFN to provide thermal sinking and low-impedance return for the synchronous rectifier.
Keep the feedback and output-sense traces short and shielded by ground copper on both sides. For the 1.8 V fixed version no external feedback divider is required, but routing the VOUT sense directly to the load side of the output capacitor (Kelvin connection) improves transient response to load steps. Avoid vias in the high-current input and LX paths; if unavoidable, use 2 to 3 parallel vias to limit inductance.
Do not use a through-hole inductor; the 2.4 MHz switching requires a low-DCR, low-AC-resistance chip inductor of 1.0 to 2.2 uH with a saturation current rating above 1 A (per Renesas datasheet). Using an undersized inductor causes severe ringing at LX and may trigger OCP. Also verify the output capacitor's ESR and voltage rating; a 10 uF X5R 6.3V ceramic is the typical choice. Operating below the minimum 2.7 V input can prevent startup or cause the LX node to stay stuck high.
Compliance Information
RoHS and lead-free per Renesas product listing. Automotive AEC-Q100 qualification status not confirmed in available data; check full datasheet for industrial/automotive grade options.
