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ESP_Midea/Midea_ESP/COMPONENT_SIZES.md
nearxos 8a26f501d8 Initial KiCad project
2026-01-04 01:19:56 +02:00

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Component Package Size Recommendations

This guide provides recommended package sizes for all components in the Midea AC Controller PCB design.

General Recommendations

For Hand Assembly (Prototyping):

  • Use 0805 (2.0mm × 1.25mm) or larger for passive components
  • Easier to solder manually
  • Better for low-volume production

For Automated Assembly (Production):

  • Use 0603 (1.6mm × 0.8mm) or 0402 (1.0mm × 0.5mm)
  • Smaller board size
  • Lower cost in volume
  • Requires pick-and-place machine

Recommended for this project: 0805 (good balance of size, cost, and ease of assembly)

Capacitors

Power Supply Capacitors (C1, C2: 10µF)

Component Value Recommended Package Alternative Notes
C1, C2 10µF 0805 (2.0×1.25mm) 0603, 1206 Ceramic, X7R or X5R, 16V or higher
Footprint: Capacitor_SMD:C_0805_2012Metric

Part Number Examples:

  • 0805: CL21A106KAYNNNE (Samsung), GRM21BR71C106KE15L (Murata)
  • 0603: CL10B106KB8NNNC (Samsung) - smaller but harder to hand solder
  • 1206: CL31A106KAHNNNE (Samsung) - larger, easier to hand solder

Voltage Rating: 16V minimum (for 5V input with margin)

Decoupling Capacitors (C3, C4, C5-C13: 100nF)

Component Value Recommended Package Alternative Notes
C3, C4, C5-C13 100nF (0.1µF) 0805 (2.0×1.25mm) 0603, 0402 Ceramic, X7R, 16V or higher
Footprint: Capacitor_SMD:C_0805_2012Metric

Part Number Examples:

  • 0805: CL21B104KBCNNNC (Samsung), GRM21BR71H104KA01L (Murata)
  • 0603: CL10B104KA8NNNC (Samsung)
  • 0402: CL05B104KA5NNNC (Samsung) - very small, difficult to hand solder

Voltage Rating: 16V minimum

Recommendation: Use 0805 for all decoupling capacitors - standard size, easy to source, good for hand assembly.

Resistors

LED Current Limiting Resistors (R1, R2: 220Ω)

Component Value Recommended Package Alternative Notes
R1, R2 220Ω 0805 (2.0×1.25mm) 0603, 1206 1/8W or 1/10W rating
Footprint: Resistor_SMD:R_0805_2012Metric

Part Number Examples:

  • 0805: RC0805FR-07220RL (Yageo), ERJ-6GEYJ221V (Panasonic)
  • 0603: RC0603FR-07220RL (Yageo)
  • 1206: RC1206FR-07220RL (Yageo) - larger, easier to hand solder

Power Rating: 1/8W (0.125W) or 1/10W (0.1W) is sufficient

  • At 3.3V: P = V²/R = 3.3²/220 = 0.049W (well within rating)

Tolerance: ±5% (E24 series) or ±1% (E96 series)

Pull-up Resistors (R3, R4, R5, R6: 10kΩ)

Component Value Recommended Package Alternative Notes
R3, R4, R5, R6 10kΩ 0805 (2.0×1.25mm) 0603, 1206 1/8W or 1/10W rating
Footprint: Resistor_SMD:R_0805_2012Metric

Part Number Examples:

  • 0805: RC0805FR-0710KL (Yageo), ERJ-6GEYJ103V (Panasonic)
  • 0603: RC0603FR-0710KL (Yageo)
  • 1206: RC1206FR-0710KL (Yageo)

Power Rating: 1/8W (0.125W) or 1/10W (0.1W) is sufficient

  • At 3.3V: P = V²/R = 3.3²/10000 = 0.001W (very low power)

Tolerance: ±5% (E24 series) is sufficient for pull-ups

LEDs

Component Type Recommended Package Alternative Notes
LED1, LED2 LED 0805 (2.0×1.25mm) 0603, 1206 Red or Green, 20mA forward current
Footprint: LED_SMD:LED_0805_2012Metric

Part Number Examples:

  • 0805:
    • Red: LTST-C170KFKT (Lite-On), L-7113HD (Kingbright)
    • Green: LTST-C170KGKT (Lite-On), L-7113GD (Kingbright)
  • 0603: Smaller, harder to see and hand solder
  • 1206: Larger, brighter, easier to see

Specifications:

  • Forward Voltage: 2.0-2.2V (Red), 3.0-3.2V (Green)
  • Forward Current: 20mA typical
  • With 220Ω resistor at 3.3V: I = (3.3V - 2.0V) / 220Ω = 5.9mA (safe, visible)

Recommendation: Use 0805 - good visibility, easy to solder, standard size.

Buttons (Switches)

Component Type Recommended Package Alternative Notes
SW1, SW2 Tactile Switch 6×6mm 4×4mm, 12×12mm Through-hole or SMD
Footprint: Button_Switch_SMD:SW_SPST_Tactile_6.0x6.0mm

Part Number Examples:

  • 6×6mm SMD: B3SN-3112P (Omron), KMR2 (C&K)
  • 6×6mm THT: B3F-4055 (Omron), KMR2 (C&K)
  • 4×4mm: Smaller, harder to press
  • 12×12mm: Larger, easier to press

Specifications:

  • Actuation Force: 2.55N (260gf) typical
  • Travel: 0.25mm typical
  • Life: 100,000+ cycles

Recommendation: Use 6×6mm - good size for finger pressing, common footprint.

Voltage Regulator (U1: AMS1117-3.3)

Component Type Package Footprint Notes
U1 AMS1117-3.3 SOT-223 Package_TO_SOT_SMD:SOT-223 1A LDO regulator

Package Dimensions:

  • Body: 6.5mm × 3.5mm
  • Height: 1.6mm
  • Lead pitch: 2.3mm

Part Number Examples:

  • AMS1117-3.3 (Advanced Monolithic Systems)
  • LM1117-3.3 (Texas Instruments) - pin-compatible alternative

Thermal Considerations:

  • Maximum power dissipation: ~1W (depends on heatsinking)
  • At 5V input, 3.3V output, 500mA: P = (5-3.3) × 0.5 = 0.85W
  • The large tab helps with heat dissipation

Recommendation: SOT-223 is standard and appropriate for this application.

Level Shifter (U3: TXB0104PWR)

Component Type Package Footprint Notes
U3 TXB0104PWR TSSOP-14 Package_SO:TSSOP-14_4.4x5mm_P0.65mm 4-channel level shifter

Package Dimensions:

  • Body: 5.0mm × 4.4mm
  • Height: 1.2mm
  • Lead pitch: 0.65mm (fine pitch)

Part Number:

  • TXB0104PWR (Texas Instruments)

Assembly Note:

  • Fine pitch (0.65mm) requires careful soldering
  • Consider using hot air rework station or reflow oven
  • Can be hand soldered with fine tip and flux

Recommendation: TSSOP-14 is the standard package for this part.

ESP32 Module (U2: ESP32-WROOM-32E)

Component Type Package Footprint Notes
U2 ESP32-WROOM-32E 38-pin QFN Custom footprint required ESP32 module

Package Dimensions:

  • Body: 18mm × 25.5mm × 3.1mm
  • Pin pitch: 1.27mm (0.05")
  • 38 pins total

Footprint:

  • You'll need to create a custom footprint or use an existing ESP32-WROOM footprint
  • Common footprint libraries may have this

Assembly Note:

  • Requires reflow soldering (hot air or reflow oven)
  • Can be hand soldered with hot air rework station
  • Bottom pad needs to be soldered for proper thermal and electrical connection

Recommendation: Use the official Espressif footprint or create custom footprint based on datasheet.

Connectors

J1: JST-XH Connector (4-pin)

Component Type Package Footprint Notes
J1 JST-XH 4-pin JST-XH-B4B-XH-A Connector_JST:JST_XH_B4B-XH-A 2.5mm pitch

Package Dimensions:

  • Pitch: 2.5mm
  • Height: ~8mm
  • Through-hole mounting

Part Number:

  • B4B-XH-A (JST) - Female connector (receptacle on PCB)
  • Matching cable connector: B4B-XH-A-1 (with cable)

Recommendation: Standard JST-XH footprint, through-hole for mechanical strength.

J2: Programming Header (6-pin)

Component Type Package Footprint Notes
J2 Pin Header 2.54mm pitch Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical Standard 0.1" pitch

Package Dimensions:

  • Pitch: 2.54mm (0.1")
  • Height: 8.5mm typical (can vary)
  • Through-hole mounting

Part Number Examples:

  • Generic pin headers available from many manufacturers
  • Can use straight or right-angle headers
  • Consider using shrouded header for keyed connection

Recommendation: Standard 2.54mm pitch header - very common, easy to source.

Summary Table

Component Type Recommended Package Size Assembly Difficulty
Capacitors (10µF) 0805 2.0×1.25mm Easy
Capacitors (100nF) 0805 2.0×1.25mm Easy
Resistors (all) 0805 2.0×1.25mm Easy
LEDs 0805 2.0×1.25mm Easy
Buttons 6×6mm 6×6mm Easy
AMS1117-3.3 SOT-223 6.5×3.5mm Medium
TXB0104PWR TSSOP-14 5.0×4.4mm Medium (fine pitch)
ESP32-WROOM-32E QFN-38 18×25.5mm Hard (requires reflow)
JST-XH Connector Through-hole 2.5mm pitch Easy
Programming Header Through-hole 2.54mm pitch Easy

Manufacturing Considerations

For Hand Assembly (Prototyping):

  • Use 0805 for all passives (capacitors, resistors)
  • Use through-hole connectors where possible
  • Use 6×6mm buttons
  • ESP32 may require hot air rework station

For Automated Assembly (Production):

  • Can use 0603 or 0402 for passives (smaller, cheaper)
  • All SMD components work with pick-and-place
  • Reduces board size
  • Lower cost in volume

Recommended for This Project:

  • 0805 for all passive components - good balance
  • Standard through-hole connectors
  • Standard SMD packages for ICs

KiCad Footprint Library References

When assigning footprints in KiCad, use these library paths:

  • Capacitors (0805): Capacitor_SMD:C_0805_2012Metric
  • Resistors (0805): Resistor_SMD:R_0805_2012Metric
  • LEDs (0805): LED_SMD:LED_0805_2012Metric
  • Buttons (6×6mm): Button_Switch_SMD:SW_SPST_Tactile_6.0x6.0mm
  • AMS1117-3.3: Package_TO_SOT_SMD:SOT-223
  • TXB0104PWR: Package_SO:TSSOP-14_4.4x5mm_P0.65mm
  • JST-XH: Connector_JST:JST_XH_B4B-XH-A
  • Programming Header: Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical

Cost Considerations

Package Size vs Cost (typical, per 1000 units):

  • 0402: Lowest cost, smallest size
  • 0603: Low cost, small size
  • 0805: Moderate cost, good size (recommended)
  • 1206: Higher cost, larger size

For this project: 0805 is the sweet spot - not too expensive, not too hard to assemble.

Availability

All recommended packages are:

  • Widely available from major distributors (Digi-Key, Mouser, LCSC, etc.)
  • Standard sizes used across the industry
  • Well-documented with datasheets and application notes
  • Compatible with standard PCB manufacturing processes