S-13R1B33-A4T2U3 - 3.3V 150mA CMOS LDO | ABLIC | HSNT-4-B
MPN: S-13R1B33-A4T2U3 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.12 | $1.12 |
| 10 | $0.98 | $9.80 |
| 100 | $0.82 | $82.00 |
| 500 | $0.71 | $355.00 |
| 1,000 | $0.62 | $620.00 |
| 3,000 | $0.55 | $1,650.00 |
S-13R1B33-A4T2U3 Overview
An LDO (Low-Dropout) linear regulator is a type of voltage regulator that maintains a stable DC output voltage even when the input-to-output differential is very small, often just a few hundred millivolts. LDOs belong to the broader linear regulator family, which sits alongside switching regulators inside the voltage regulator category of power management ICs. Unlike switching regulators that use energy-storage magnetics and switching pulses, an LDO dissipates excess input voltage as heat, which trades efficiency for exceptionally low output noise and high power-supply rejection ratio (PSRR).
Key features of the S-13R1B33-A4T2U3 include 150 mA continuous output current, fixed 3.3 V output with high accuracy, low quiescent current consumption, and integrated reverse-current protection that prevents current flow from the output back into the input when VIN collapses. The CMOS process enables small package footprint and low standby power, while the HSNT-4-B exposed thermal pad keeps junction temperature in check at moderate ambient loads. The part is also available across the wider S-13R1 series with output voltages ranging from approximately 1.0 V to 3.6 V, all sharing the same HSNT-4-B footprint.
Typical applications for the S-13R1B33-A4T2U3 include portable and battery-powered devices (sensor nodes, wearables, remote controls), IoT endpoints, low-power MCUs and BLE modules with 3.3 V rails, and as a post-filter stage after a switching DC-DC converter to deliver clean power to noise-sensitive analog blocks. The 3.3 V fixed output is especially useful for digital logic rails.
When designing with this regulator, observe the maximum input voltage limit and verify that the input-output voltage differential at minimum VIN remains above the dropout specification at the worst-case 150 mA load. Place input and output ceramic bypass capacitors as close as possible to the device pins to ensure loop stability.
Drop-in alternatives for S-13R1B33-A4T2U3 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with S-13R1B33-A4T2U3 (same form factor and footprint) — differing in Output Voltage, Package, Regulator Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
S-13R1B33-I4T1U3
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S-13R1C33-A4T2U3
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S-13R1B30-A4T2U3
✅ Drop-In📋 Reference alternative (not in catalog)
S-13R1B25-A4T2U3
✅ Drop-In📋 Reference alternative (not in catalog)
S-13R1B18-A4T2U3
✅ Drop-In📋 Reference alternative (not in catalog)
NJM2835DL1-05-TE1
✅ Drop-In✓ In Stock
$0.09 / Unit
View Datasheet →S-13R1B33-A4T2U3 Maximum Ratings & Electrical Characteristics
| Regulator Type | Linear, LDO, Positive Fixed |
| Output Voltage | 3.3 V (fixed) |
| Maximum Output Current | 150 mA |
| Number of Outputs | 1 |
| Reverse Current Protection | Yes (integrated) |
| Package | HSNT-4-B (4-pin, flat lead, exposed thermal pad) |
| Mounting Type | Surface Mount |
| Process Technology | CMOS |
S-13R1B33-A4T2U3 Pin Configuration
| Pin 1 | VDD — Power supply input (VIN) |
| Pin 2 | GND — Ground reference |
| Pin 3 | VOUT — Regulated 3.3 V output |
| Pin 4 | VOUT — Regulated 3.3 V output (bonded to pin 3 internally for low-impedance path) |
Typical Applications
S-13R1B33-A4T2U3 is suitable for 6 applications: Battery-Powered IoT Sensor Nodes, 3.3 V MCU and BLE Module Power Rail, Post-Filter Stage After Switching DC-DC Converter, Wearables and Health-Monitoring Patches, Industrial Sensor and Field Transmitter Rails, USB-Powered Peripheral 3.3 V Rail.
Battery-Powered IoT Sensor Nodes
The ABLIC S-13R1B33-A4T2U3 fits battery-powered IoT sensor nodes because its CMOS architecture delivers very low quiescent current while still providing a stable 3.3 V rail for low-power MCUs, BLE radios, and sensor ICs. With 150 mA of continuous output current, the part easily handles the peak bursts of a transmitting BLE SoC plus a handful of digital sensors. Its integrated reverse-current protection is a key safety feature when the node uses a load-dump or power-mux arrangement with a small backup supercapacitor, preventing back-feeding into a depleted primary cell. Place a 1 µF X7R ceramic bypass on VIN and a 1 µF X7R on VOUT, both within 2 mm of the package, to ensure the regulator stays stable across the wide temperature and load transients typical of an outdoor sensor enclosure.
Recommended
3.3 V MCU and BLE Module Power Rail
The S-13R1B33-A4T2U3 is a natural fit for the 3.3 V rail of MCUs and BLE/Wi-Fi modules that draw less than 150 mA peak. Its fixed 3.3 V output eliminates the need for feedback resistors, simplifying the BOM and shrinking PCB area in space-constrained wearables or remote-control designs. Compared with a switching regulator, the LDO adds no high-frequency noise to the supply, which improves RF receiver sensitivity and reduces ADC code noise on nearby analog channels. The exposed thermal pad of the HSNT-4-B package spreads heat efficiently across a small copper pour, so even at 100 mA continuous load with a 1 V dropout the junction temperature rise is modest.
Recommended
Post-Filter Stage After Switching DC-DC Converter
Use the S-13R1B33-A4T2U3 as a post-filter LDO after a switching DC-DC converter to deliver a clean 3.3 V rail to noise-sensitive analog blocks such as ADCs, DACs, op-amps, or sensor front-ends. The CMOS LDO provides high PSRR at low to mid frequencies, attenuating the residual switching ripple that the buck converter cannot fully reject. At 150 mA the part is well-matched to typical sensor and analog front-end current budgets. The HSNT-4-B footprint places this post-filter only millimeters from the load, minimizing the high-impedance trace that could otherwise pick up switching noise. Add a small ferrite bead between the buck output and the LDO input for additional filtering of high-frequency ripple.
Recommended
Wearables and Health-Monitoring Patches
The S-13R1B33-A4T2U3 supports wearable health-monitoring patches where a coin-cell or Li-ion battery feeds a 3.3 V rail for a low-power MCU, optical heart-rate sensor, and accelerometer. Its CMOS low-Iq design extends battery life between charges, while the integrated reverse-current protection prevents the wearable from back-driving a charging IC during hot-swap events. The HSNT-4-B package measures only a couple of square millimeters, fitting easily on a flex PCB inside a wristband or chest patch. A 1 µF ceramic input capacitor and 1 µF ceramic output capacitor are sufficient for stability, keeping the external BOM to two small capacitors.
Recommended
Industrial Sensor and Field Transmitter Rails
For industrial 4-20 mA loops, factory automation modules, and remote field transmitters, the S-13R1B33-A4T2U3 delivers a regulated 3.3 V rail from a 24 V bus through a pre-regulator. Its 150 mA rating covers most sensor-interface ASICs and isolated digital isolators used in industrial nodes. The integrated reverse-current protection prevents damage when the 24 V bus is removed and the local hold-up capacitor would otherwise discharge back through the LDO. The HSNT-4-B package with exposed pad tolerates the wider industrial ambient temperature range when paired with adequate PCB copper area. Designers should pair this LDO with a TVS diode and input fuse for full IEC 61000-4 transient immunity.
Recommended
USB-Powered Peripheral 3.3 V Rail
The S-13R1B33-A4T2U3 is a clean downstream regulator for USB peripherals such as HID devices, dongles, and low-speed data loggers that derive power from a USB 5 V rail. A USB controller or low-power MCU typically requires a 3.3 V supply, and the LDO's low dropout and low noise make it well-suited to deriving that rail directly without a switching converter. The 150 mA current rating comfortably covers USB HID devices, low-speed sensors, and indicator LEDs. The HSNT-4-B's tiny footprint is unobtrusive inside a USB stick form factor, and the exposed pad provides thermal relief during continuous bus-powered operation.
Recommended
Recommended Products Summary
Engineering reference data for S-13R1B33-A4T2U3 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | S-13R1B33-I4T1U3 | S-13R1C33-A4T2U3 | S-13R1B30-A4T2U3 | S-13R1B25-A4T2U3 | NJM2835DL1-05-TE1 |
|---|---|---|---|---|---|---|
| Brand | ABLIC | ABLIC | ABLIC | ABLIC | ABLIC | NJR |
| Package | HSNT-4-B (4-pin, exposed pad) | HSNT-4-B - same | HSNT-4-B - same | HSNT-4-B - same | HSNT-4-B - same | SOT-23-5 equivalent - similar footprint |
| Output Voltage | 3.3 V | 3.3 V | 3.3 V | 3.0 V | 2.5 V | 5.0 V |
| Output Current | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA |
| Regulator Topology | CMOS LDO, fixed | CMOS LDO, fixed | CMOS LDO, fixed | CMOS LDO, fixed | CMOS LDO, fixed | Bipolar LDO, fixed |
| Process Technology | CMOS | CMOS | CMOS | CMOS | CMOS | Bipolar |
| Param Match Percentage | 100% (reference) | 100% | 95% | 90% | 80% | 80% |
Key Differentiators
- Integrated reverse-current protection (vs NJM2835DL1-05-TE1)
- Same-family pin-to-pin voltage scaling (vs S-13R1B30-A4T2U3)
- CMOS process enables lower quiescent current than bipolar LDOs (vs NJM2835DL1-05-TE1)
Design Notes
Place the input and output ceramic capacitors as close as possible to the S-13R1B33-A4T2U3 pins, ideally within 2 mm. Use X7R 1 µF capacitors or larger on both VIN and VOUT to ensure loop stability across the full -40 °C to +85 °C range. Solder the exposed thermal pad of the HSNT-4-B package to a copper pour of at least 10 mm² to keep the junction temperature within the datasheet limits under sustained 150 mA load.
At VIN = 5 V, VOUT = 3.3 V, and IOUT = 150 mA, the S-13R1B33-A4T2U3 dissipates approximately (5 V − 3.3 V) × 0.150 A = 0.255 W. With a typical HSNT-4-B θJA near 100 °C/W on a 4-layer 1-oz PCB, the junction temperature rises only ~25 °C above ambient, so no heatsink is required. Estimated: thermal rise assumes 1-oz copper pours on top and bottom layers; a 2-layer board will run hotter and may need a thermal via array under the exposed pad.
Do not exceed the maximum input voltage of the S-13R1B33-A4T2U3 specified in the ABLIC datasheet. The integrated reverse-current protection prevents back-feeding but is not a substitute for an upstream TVS diode on hot-plug or inductive-load rails. Avoid operating continuously at the absolute maximum VIN with the minimum dropout margin - leave at least 0.3 V of headroom for AC line transients and load-step recovery. Do not omit the output capacitor: the part requires a minimum ESR below a few hundred milliohms for stable regulation.
Compliance Information
RoHS and lead-free status inferred from ABLIC product page (HSNT-4-B package is a standard ABLIC Pb-free form factor); halogen-free status and AEC-Q100 grade not stated in the public S-13R1 datasheet excerpt.
