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SOT-223 · AMS1117-5.0
Active1A LDO Regulator (5V)
AMS1117-5.0
Advanced Monolithic Systems · SOT-223 · 1A LDO Regulator (5V)
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Overview
The AMS1117-5.0 is the 5 V output version of the 1117 low-dropout family and exists mainly to shrink the classic LM7805 onto a surface-mount pad. It delivers up to 1 A from a 6.5 V to 15 V input with a 1.1 V typical dropout at 800 mA — roughly 0.9 V better than a 78xx part — which lets a 7 V or 9 V rail, or a 6 V wall-wart after diode losses, still produce a clean 5 V where an LM7805 would have fallen out of regulation. The pass element is a PNP transistor referenced to a Zener-trimmed bandgap, giving about ±1% initial accuracy, 0.2% maximum line regulation and 0.4% maximum load regulation, and the three-lead SOT-223 pinout (ground, output, input, with the tab bonded to output) is identical to LM1117-5.0, AZ1117-5.0 and SPX1117-5.0.
Two limits decide whether this part survives in your product. The first is ground current: 5 mA typical and 10 mA maximum at any load, drawn from the input pin and dumped as heat, which makes the part unsuitable for standby-critical battery designs where an HT7533-class LDO draws 4 µA. The second is package thermodynamics. All dissipation leaves through the SOT-223 tab, and with roughly 60 °C/W junction-to-ambient on a modest pad you have about 1.6 W of budget at 25 °C ambient against a 125 °C junction limit. A 9 V to 5 V conversion at 1 A is 4 W plus ground current, which is unachievable without a large pour, thermal vias and airflow; at 300 mA it is a comfortable 1.2 W. If your application needs 5 V at more than about 400 mA from a 9 V or higher rail, the correct answer is a buck converter such as the LM2596-5.0 or MP1584EN, not a bigger pad.
On-chip protection mirrors the rest of the family: current limiting near 1.2 A to 1.5 A and thermal shutdown around 150 °C junction, with safe-area compensation on the pass device. Stability requires at least 10 µF of low-ESR output capacitance — 22 µF X5R ceramic is the modern choice, derated for DC bias — placed close to the output pin, plus 10 µF input bypass when the source is remote. Note that the 5 V version has the largest input-to-output headroom requirement of the 1117 family, so a 5 V-in design is pointless: use a 5 V input only with the adjustable version or an LDO specified for sub-200 mV dropout.
Sourcing considerations: because the AMS1117-5.0 competes directly with the LM7805 in TO-220 and the LM2940/LM2936 low-dropout 5 V parts, several vendors offer equivalents, and pricing is stable in the low-cent range at reel quantities. Counterfeit risk is real — remarked 3.3 V die, re-tinned pulls and lower-current substitutes all circulate. Incoming inspection should confirm 5.0 V output under a 500 mA to 1 A load, measure ground current against the 5 mA to 10 mA window, and verify dropout by dropping the input to 6.5 V. Our Shenzhen stock is MOQ 100 pcs loose or 2,500 pcs on tape-and-reel, shipping in one to two business days, with sample load-testing and a certificate of conformance available on request.
Key Features
- Fixed 5 V at up to 1 A from a 6.5 V to 15 V input in SOT-223
- About 0.9 V lower dropout than an LM7805 — usable from a 7 V rail
- ±1% initial accuracy with 0.2% line and 0.4% load regulation
- Current limiting plus thermal shutdown integrated, no external parts needed
- Footprint-compatible with LM1117-5.0, AZ1117-5.0 and SPX1117-5.0
Typical Applications
- Surface-mount replacement for TO-220 LM7805 on 5 V logic and peripheral rails
- USB host and device 5 V supplies from a 7 V to 9 V adapter
- Relay, sensor and display modules needing a clean 5 V at a few hundred milliamps
- Networking and telecom boards with distributed 5 V point-of-load
- Repair and retrofit of legacy 7805 designs onto SMD production lines
Specifications
- Output Voltage
- 5 V
- Input Voltage
- 6.5 to 15 V
- Output Current (Max)
- 1 A
- Dropout Voltage (Typ, IOUT = 800 mA)
- 1.1 V
- Quiescent Current (Max)
- 10 mA
- Line Regulation (Max)
- 0.2 %
- Load Regulation (Max)
- 0.4 %
- Output Capacitor (Min for Stability)
- 10 µF
- Pins
- 3
- RoHS
- Compliant
Procurement Tips
Quote the AMS1117-5.0 with a defined copper pour and via pattern on the PCB notes, and if your load exceeds 400 mA from a 9 V or higher rail, ask us to price the MP1584EN or LM2596-5.0 as the primary solution before committing to a linear topology.
Frequently Asked Questions
AMS1117-5.0 versus LM7805 — which do I choose for a 5 V rail?
Choose by input voltage and mounting. The LM7805 needs at least 7 V and drops 2 V at 1 A, comes in a TO-220 that can be bolted to a heatsink, and handles a 35 V input. The AMS1117-5.0 needs only about 6.2 V to 6.5 V at full load, drops 1.1 V to 1.3 V, solders flat to a PCB pad and is limited to a 15 V input. For a 12 V or 24 V rail neither linear part is efficient — both waste the difference as heat — so use a buck converter and keep the LDO for post-regulation if noise matters.
Can I use the AMS1117-5.0 from a 5 V USB input to get a regulated 5 V?
No. With a 1.1 V to 1.3 V dropout the part cannot regulate from a 5 V input; the output will sit near 3.8 V to 4 V and follow the input down as the cable sags. Use a true low-dropout 5 V regulator with sub-200 mV dropout such as the LM2936, MCP1703-500 or a dedicated USB power switch with a pass FET, or step down from a higher rail instead.
How much copper does the SOT-223 tab need?
As much as you can afford, connected with vias to inner planes. A single-sided 1 cm square pad gives roughly 60 °C/W junction-to-ambient, so about 1.6 W of budget at 25 °C ambient against a 125 °C limit. Doubling the area and adding a via array to an internal ground plane can bring that to 40 °C/W to 45 °C/W. Never rely on the package alone at 1 A: at 9 V in the device dissipates 4 W and will thermal-cycle regardless of copper.
What capacitors are required, and can I use all-ceramic?
Yes, all-ceramic works provided the capacitance is adequate: 22 µF X5R or X7R at the output (which behaves like 12 µF to 15 µF at 5 V bias) and 10 µF at the input, plus 100 nF high-frequency bypass at each pin. The datasheet's 10 µF minimum historically referred to tantalum; if you use tantalum, observe polarity and derate voltage by at least 2x. If the converter shows a few hundred millivolts of ringing on load steps, the output capacitance or its placement is the first thing to fix.
Is the AMS1117-5.0 counterfeit-prone?
Yes — the 1117 family is among the most remarked regulator families in the broker market, and the 5 V version is often substituted with 3.3 V die carrying a corrected top mark or with lower-current clones. Test rather than trust: load a sample to 1 A and check that the output holds 5 V ±2% and that case temperature rise matches your thermal calculation, measure ground current (5 mA to 10 mA genuine), and confirm the dropout point by walking the input down to 6.5 V. Physically, laser-etched marking, matte tin leads and clean moulding are the baseline checks; acetone-wiped ink is an immediate reject.
What alternatives should I qualify as a second source?
Footprint-identical: LM1117MPX-5.0 (TI), AZ1117-5.0 (Diodes Incorporated), SPX1117M5-5-0 (Exar/MaxLinear) and UMW AMS1117-5.0. Lower quiescent current: MCP1703-500, HT7550 or ME6211C50, at reduced current capability. Higher current in a similar outline: LM2940IMP-5.0 (1 A, low dropout) or a 3 A buck such as the MP1584EN if efficiency matters. Add the approved-vendor list to the BOM so the assembler cannot substitute unqualified equivalents.
What is the MOQ and lead time?
MOQ is 100 pcs loose for prototypes or 2,500 pcs on tape-and-reel in SOT-223. Shenzhen stock ships in one to two business days; authorised-channel replenishment for Advanced Monolithic Systems and Diodes Incorporated equivalents is four to eight weeks.
Alternatives & Equivalents
LM7805
onsemi
alternative
AMS1117-2.5
Advanced Monolithic Systems
equivalent
AMS1117-3.3
Advanced Monolithic Systems
equivalent
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