component
TD9521B
Public Made by Adomby adom
Techcode Semicon Power Distribution Switches, SOT-23-5. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownTD9521B
Techcode Semicon · Power Distribution Switches · SOT-23-5
TD9521B from Techcode Semicon, in a SOT-23-5. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VOUT | power_out | Output voltage pin that follows the input voltage through the 35mΩ N-channel power switch, and is discharged by an internal resistor when ENB is high or EN is low (datasheet text, as printed). |
| 2 | GND | power_in | Ground reference pin for the device; the datasheet gives no further electrical limit for this pin. |
| 3 | ISET | passive | Current-limit set pin: the current-limit threshold is ILim = 120k × 1.14 V / Riset, so Riset to ground programs the limit (Riset = 51 kΩ gives 2.5 to 2.85 A in the electrical characteristics). |
| 4 | EN | input | Enable input: high enables the device and low disables it, and the EN pin cannot be left floating. |
| 5 | VIN | power_in | Power supply input that connects to the external DC supply, rated 3.5 V to 5.5 V in the recommended operating conditions. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Techcode Semicon |
| Package | SOT-23-5 |
| Category | Power Management (PMIC) |
| Pins | 5 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| VIN Input Voltage (VIN to GND) | VIN | -0.3 | 7 | V | 2 | ||
| VOUT to GND Voltage | VOUT | -0.3 | 7 | V | 2 | ||
| EN to GND Voltage | VEN | -0.3 | 7 | V | 2 | ||
| ISET to GND Voltage | VISET | -0.3 | 7 | V | 2 | ||
| Maximum Junction Temperature | TJ | 150 | oC | 2 | |||
| Storage Temperature Range | TSTG | -65 | 150 | oC | 2 | ||
| Maximum Soldering Temperature Range | TSDR | 260 | oC | 10 seconds | 2 | ||
| VIN Input Voltage (VIN to GND) | VIN | 3.5 | 5.5 | V | 3 | ||
| Output current | IOUT | 0 | 3 | A | 3 | ||
| Ambient Temperature | TA | -40 | 85 | oC | 3 | ||
| Junction Temperature | TJ | -40 | 125 | oC | 3 | ||
| VIN Supply Current | 1 | μA | No load, VEN=0V | 4 | |||
| VIN Supply Current | 120 | 150 | μA | No load, VEN=5V | 4 | ||
| Leakage Current | 1 | μA | VOUT=GND, VEN=0V | 4 | |||
| Reverse Leakage Current | 1 | μA | VIN=GND, VOUT=5V, VEN=0V | 4 | |||
| Power Switch On Resistance | RDS(ON) | 35 | 38 | mΩ | IOUT=1A, TA= 25℃ | 4 | |
| Current Limit Threshold | ILIM | 1.1 | 3.9 | A | iset | 4 | |
| Current Limit Threshold | 2.5 | 2.6 | 2.85 | A | Riset=51k | 4 | |
| Short-Circuit Output Current | ISHORT | 80 | 95 | % | 4 | ||
| EN Input Current | 1 | μA | 4 | ||||
| Junction-to-Ambient Resistance in Free Air | θJA | 235 | oC/W | Free air | 3 |
CAD (KiCad official)
- Symbol:
TD9521B - Footprint:
Package_TO_SOT_SMD:SOT-23-5 - 3D model: SOT-23-5 (KiCad packages3D, STEP)
- 3D model files:
td9521b-etched.step/td9521b-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);td9521b.step/td9521b.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Techcode Semicon datasheet (10 pp, sha256
c0da5a40e7e31cb8, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).