REG104GA-3.3 - 1A, 15V LDO Regulator 3.3V Fixed | Texas Instruments
MPN： REG104GA-3.3 ✓ 啟用中REG104GA-3.3 概覽
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 voltage differential approaches the pass element's saturation limit. LDOs belong to the broader family of linear regulators, which in turn fall under voltage regulators and ultimately power management ICs. Because LDOs dissipate excess voltage as heat rather than switching it, they add no high-frequency switching noise to the output - making them the preferred choice for noise-sensitive analog and mixed-signal power rails.
The REG104GA-3.3 delivers up to 1A of output current from a wide input range up to 15V (with 3.3V fixed output) while consuming low quiescent current. Its DMOS pass element gives it a low dropout typical for the topology, enabling 3.3V regulation from inputs as low as approximately 4.0V at full load. Internal protection includes current limit and thermal shutdown. The 6-pin SOT-223 package provides a low thermal resistance path through the exposed tab, allowing reliable 1A operation with adequate copper pad area.
Typical applications include point-of-load regulation after a switching converter, USB and embedded system 3.3V rails, industrial sensor and PLC modules, and post-regulation for noise-sensitive analog blocks such as ADCs and DACs. Compared to a buck regulator at the same node, the REG104 adds zero switching ripple at the cost of dissipating (VIN - 3.3V) * 1A as heat.
When designing with this part, place input/output ceramic capacitors close to the pins per the datasheet, ensure the exposed tab has sufficient copper area for thermal dissipation, and respect the 15V absolute maximum input rating. The enable pin allows sequenced power-up in multi-rail systems.
直接替換替代品，適用於 REG104GA-3.3 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： REG104GA-3.3 （相同外形與佔位） — 差異在於 Operating Temperature Range, Output Type, Package, Topology.
REG104GA-2.5
✅ 直接替換📋 參考替代品（不在目錄中）
REG104GA-5
✅ 直接替換📋 參考替代品（不在目錄中）
REG104GA-A
✅ 直接替換📋 參考替代品（不在目錄中）
REG104GA-3.3G4
✅ 直接替換📋 參考替代品（不在目錄中）
REG104GA-3.3/2K5
✅ 直接替換📋 參考替代品（不在目錄中）
REG104GA-3.3 最大額定值與電氣特性
| 拓撲 | LDO (Low-Dropout Linear Regulator) |
| Pass Element | DMOS |
| 輸出類型 | Fixed (3.3 V) |
| Input Voltage (Max) | 15 V |
| 輸出電流 (最大) | 1 A |
| 致能腳位 | Yes (active-high) |
| 工作溫度範圍 | -40 C to +85 C |
| 封裝 | SOT-223-6 (DCQ) with tab |
| 安裝類型 | Surface Mount |
| RoHS 狀態 | Compliant |
REG104GA-3.3 腳位配置
| 腳位 1 | IN — Input supply voltage (up to 15V) |
| 腳位 2 | GND — Ground |
| 腳位 3 | EN — Enable (active-high) |
| 腳位 4 | NC — Not connected (per datasheet) |
| 腳位 5 | OUT — Regulated 3.3V output |
| 腳位 6 | TAB — Exposed thermal tab (electrically connected to GND/thermal pad) |
典型應用
REG104GA-3.3 適用於 6 應用s: Point-of-Load 3.3V Rail after Switching Pre-Regulator, USB / Embedded System 3.3V Power Rail, Industrial Sensor and PLC Module Power, Analog-to-Digital Converter Reference Supply, Automotive Infotainment / Body Electronics Auxiliary Rail, FPGA / DSP Auxiliary 3.3V Rail.
Point-of-Load 3.3V Rail after Switching Pre-Regulator
The REG104GA-3.3 is ideal as a post-regulator that follows a 5V or 12V switching converter to deliver a clean, ripple-free 3.3V rail. Its 1A output current and 15V max input cover the common 5V/12V bus range, while the LDO topology removes switching noise from the output - critical for analog and mixed-signal loads. Place a 1uF-10uF ceramic input cap and 1uF-10uF ceramic output cap close to the pins. Versus a second buck stage, the REG104 adds zero switching ripple at the cost of dissipating (VIN - 3.3V) x IOUT as heat.
推薦
USB / Embedded System 3.3V Power Rail
USB and embedded microcontroller platforms often require a regulated 3.3V rail from a 5V input. The REG104GA-3.3's fixed 3.3V output, 1A capability, and 15V max input handle USB 5V VBUS cleanly while tolerating transient surges above 5V. The enable pin lets a host MCU or USB power switch gate the rail for power sequencing or suspend-mode shutdown. The SOT-223-6 footprint fits standard low-cost PCB layouts used in development boards and consumer peripherals.
推薦
Industrial Sensor and PLC Module Power
Industrial sensors and PLC I/O modules often run from 24V (nominal 12-15V after protection/filtering) and need a stable 3.3V rail for low-voltage logic. The REG104GA-3.3's 15V input ceiling fits standard industrial rails, and its -40C to +85C operating range suits factory-floor environments. The LDO's lack of switching noise also benefits analog front-end and transducer excitation circuits where clean supply improves measurement repeatability and signal-to-noise ratio.
推薦
Analog-to-Digital Converter Reference Supply
Precision ADCs require low-noise reference and analog supplies to achieve datasheet SNR and INL. The REG104GA-3.3, with its linear LDO topology, adds no switching ripple and provides the quiet 3.3V rail that many SAR and delta-sigma ADCs need for AVDD or VREF. The 1A output is sufficient to power the ADC plus surrounding op-amps and reference buffers. Place input/output ceramic capacitors per the datasheet to optimize PSRR across the ADC's sampling frequency harmonics.
推薦
Automotive Infotainment / Body Electronics Auxiliary Rail
In automotive infotainment and body controllers, 12V battery rails power many sub-blocks that need a local 3.3V supply. The REG104GA-3.3's 15V input ceiling handles 12V nominal with margin for load-dump transients (with external TVS protection), and its DMOS pass element delivers low dropout for cold-crank scenarios. The 1A output supports small SoCs, CAN transceivers, and display backlight drivers. Note: this part is industrial-grade, not AEC-Q100 - automotive safety-critical rails require a Q1-qualified alternative.
推薦
FPGA / DSP Auxiliary 3.3V Rail
FPGAs and DSPs typically require multiple rails (1.0V core, 1.8V, 3.3V I/O). The REG104GA-3.3 provides the 3.3V I/O rail from a 5V intermediate bus, with 1A output covering most auxiliary logic and LVCMOS I/O banks. The enable pin supports power sequencing - the 3.3V rail can be asserted before the core rail using simple logic. Compared to a buck regulator, the LDO removes switching noise that could couple into adjacent analog I/O or sensitive clock distribution.
推薦
推薦產品摘要
工程參考資料，適用於 REG104GA-3.3 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | REG104GA-2.5 | REG104GA-5 | REG104GA-A | REG104GA-3.3G4 | REG104GA-3.3/2K5 |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOT-223-6 (DCQ) | SOT-223-6 (DCQ) - same | SOT-223-6 (DCQ) - same | SOT-223-6 (DCQ) - same | SOT-223-6 (DCQ) - same | SOT-223-6 (DCQ) - same |
| Output Voltage | 3.3 V (fixed) | 2.5 V (fixed) | 5.0 V (fixed) | Adjustable | 3.3 V (fixed) | 3.3 V (fixed) |
| Output Current (Max) | 1 A | 1 A | 1 A | 1 A | 1 A | 1 A |
| Input Voltage (Max) | 15 V | 15 V | 15 V | 15 V | 15 V | 15 V |
| Topology / Pass Element | DMOS LDO | DMOS LDO | DMOS LDO | DMOS LDO | DMOS LDO | DMOS LDO |
| Enable Pin | Yes (active-high) | Yes (active-high) | Yes (active-high) | Yes (active-high) | Yes (active-high) | Yes (active-high) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
主要差異化特點
- DMOS pass element for low dropout and fast transient response (對比REG104GA-2.5)
- Fixed 3.3V output eliminates external resistor divider (對比REG104GA-A)
- Active-high enable pin for sequenced power-up (對比REG104 family parts without EN)
設計說明
At VIN=5V, VOUT=3.3V, and IOUT=1A the REG104GA-3.3 dissipates approximately 1.7W. The SOT-223-6 thermal pad is the primary heat path - per the TI REG104 datasheet, junction-to-ambient thermal resistance depends heavily on PCB copper area. A minimum copper pad of roughly 1 square inch on the top layer plus thermal vias to inner/outer planes is recommended to keep junction temperature rise within safe limits at full 1A load across the -40C to +85C ambient range.
Place the input and output ceramic capacitors as close to the REG104GA-3.3 pins as possible, ideally within 2-3mm. The TI REG104 datasheet specifies input and output capacitor values and ESR ranges - typically 1uF to 10uF X7R/X5R ceramic. Route the enable pin away from noisy switching traces; if not used, tie EN to IN through a 100kohm resistor or directly to IN for always-on operation. Provide adequate ground copper under the device for both electrical and thermal performance.
Do not exceed the 15V absolute maximum input rating - transients above 15V (e.g., from a 12V automotive load-dump event) can permanently damage the part; add a TVS or upstream protection if the input bus can spike above 15V. The enable pin is active-high; do not leave it floating in noisy systems. Confirm that the input voltage always remains above VOUT + dropout at full load, especially during cold-crank or low-line conditions, to avoid the regulator dropping out of regulation.
合規資訊
RoHS compliant per TI product page. Industrial-grade (-40C to +85C), not AEC-Q100 qualified - automotive safety-critical applications require a Q1-qualified alternative such as TPS7A2633DRVR. Halogen-free status not explicitly listed in the provided data.
