STM32 F 1 03 C 8 T 6
  │   │ │  │ │ │ │ │
  │   │ │  │ │ │ │ └── Temperature range (6 = -40 to 85°C)
  │   │ │  │ │ │ └── Package (T = LQFP)
  │   │ │  │ │ └── Flash size (8 = 64KB)
  │   │ │  │ └── Pin count (C = 48 pins)
  │   │ │  └── Line (03 = access line)
  │   │ └── Core (1 = Cortex-M3)
  │   └── Type (F = Mainstream)
  └── Family (STM32)

STM32F103C8T6
│     │  │││││
│     │  ││││└── 6 = -40 to +85°C
│     │  │││└── T = LQFP package
│     │  ││└── 8 = 64KB Flash
│     │  │└── C = 48 pins
│     │  └── 03 = Access line (medium density)
│     └── F1 = Mainstream Cortex-M3
└── STM32 family

Result: Mainstream M3 MCU, 48-pin LQFP, 64KB Flash, Industrial temp
Common Name: "Blue Pill" MCU

STM8 S 003 F 3 P 6
  │  │  │  │ │ │ │
  │  │  │  │ │ │ └── Temperature range
  │  │  │  │ │ └── Package
  │  │  │  │ └── Flash size
  │  │  │  └── Pin count
  │  │  └── Line
  │  └── Type (S=Standard, L=Low-power, A=Automotive)
  └── STM8 family

ST [Package] [Current] [Channel] [Voltage] [Suffix]
│     │         │         │         │         │
│     │         │         │         │         └── Technology (F, L, etc.)
│     │         │         │         └── Voltage class (20=200V, 25=250V)
│     │         │         └── Channel (N=N-ch, P=P-ch)
│     │         └── Current rating (amps)
│     └── Package code (F, P, D, B, W)
└── ST prefix

STF5N52U
│││ │ ││
│││ │ │└── U = technology suffix
│││ │ └── 52 = 520V class
│││ └── N = N-channel
││└── 5 = ~5A rating
│└── F = TO-220FP package
└── ST prefix

L 78 [Voltage] [Grade] [Package]
│  │     │        │        │
│  │     │        │        └── Package suffix
│  │     │        └── Temperature grade (optional)
│  │     └── Output voltage (05=5V, 12=12V, etc.)
│  └── 78=Positive, 79=Negative
└── L prefix (ST designation)

L7805CV
│ ││ ││
│ ││ │└── V = through-hole variant
│ ││ └── C = Commercial grade
│ │└── 05 = 5V output
│ └── 78 = Positive regulator
└── L prefix

L7912ACD2T
│ ││ │ │ │
│ ││ │ │ └── T = tape packaging
│ ││ │ └── D2 = D²PAK
│ ││ └── AC = standard temp grade
│ │└── 12 = -12V output
│ └── 79 = Negative regulator
└── L prefix

// WRONG - Tries to match last 2 chars as package+temp
String lastTwo = upperMpn.substring(upperMpn.length() - 2);
// For STM32F103C8T6: lastTwo = "T6"
// Then validates: "TUVRY".indexOf('T') >= 0 && isDigit('6')
// This passes but returns "T6" instead of just "T" (LQFP)

// STM32F103C8T6 → Package is second-to-last char: "T"
if (upperMpn.startsWith("STM32") && upperMpn.length() >= 2) {
    char packageChar = upperMpn.charAt(upperMpn.length() - 2);
    return switch (packageChar) {
        case 'T' -> "LQFP";
        case 'H' -> "BGA";
        case 'U' -> "VFQFPN";
        case 'Y' -> "WLCSP";
        case 'P' -> "TSSOP";
        default -> String.valueOf(packageChar);
    };
}

// Extract from prefix: STF = TO-220FP, STP = TO-220, STD = DPAK
if (upperMpn.startsWith("STF")) return "TO-220FP";
if (upperMpn.startsWith("STP")) return "TO-220";
if (upperMpn.startsWith("STD")) return "DPAK";
if (upperMpn.startsWith("STB")) return "D2PAK";
if (upperMpn.startsWith("STW")) return "TO-247";

// STM32F103C8T6 → Series: STM32F103 (or STM32F1)
// For STM32: Extract up to and including line number
if (upperMpn.startsWith("STM32")) {
    // STM32 + Type + Core + Line = STM32F103
    // Match pattern: STM32[A-Z][0-9]{1,3}
    Pattern p = Pattern.compile("^(STM32[A-Z][0-9]{1,3})");
    Matcher m = p.matcher(upperMpn);
    if (m.find()) return m.group(1);
}

// STM32/STM8: Package is second-to-last character
if (upperMpn.startsWith("STM32") || upperMpn.startsWith("STM8")) {
    char packageChar = upperMpn.charAt(upperMpn.length() - 2);
    return switch (packageChar) {
        case 'T' -> "LQFP";
        case 'H' -> "BGA";
        case 'U' -> "VFQFPN";
        // ...
    };
}

// MOSFETs: Package is in prefix
if (upperMpn.startsWith("STF")) return "TO-220FP";
if (upperMpn.startsWith("STP")) return "TO-220";
// ...

// Voltage regulators: Strip prefix and grade, then match suffix
String suffix = upperMpn.replaceFirst("^[LM]C?7[89]\\d{2}", "")
                       .replaceFirst("^[A-C]{1,2}", "");
// CV → TO-220, D2T → D2PAK, etc.