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SMD code 7Dd

Marking codes are not standardised, and the same code is reused by unrelated makers for unrelated parts. Below is every part in our tables printed with it, and any printed with a code that is easy to misread as it, from the manufacturers' own marking tables and published code lists.

The last letter, d, is lower case, which on NXP and Philips parts is a date or factory code, so it was set aside and 7D was searched.

97 parts are printed 7Dd

Not sure which one you have?

Answer up to 4 quick questions and these 50 parts are ranked, with a meter test that settles it. It works on a dead part too.

  • NSBC114YDXV6SOT-563Digital transistor (NPN, resistors built in), 6 pins, onsemiDigital transistor (NPN, resistors built in)SOT-5636 pinsonsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    onsemi
    Package
    SOT-563
    Pins
    6
    Details
    Dual NPN Bias Resistor Transistors R1 = 10 k  , R2 = 47 k 
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor NSBC114YDXV6, opens in a new tab
  • NSVBC114YDXV6SOT-563Digital transistor (NPN, resistors built in), 6 pins, onsemiDigital transistor (NPN, resistors built in)SOT-5636 pinsonsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    onsemi
    Package
    SOT-563
    Pins
    6
    Details
    Dual NPN Bias Resistor Transistors R1 = 10 k  , R2 = 47 k 
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor NSVBC114YDXV6, opens in a new tab
  • NSVMUN5214DW1SOT-363Digital transistor (NPN, resistors built in), 6 pins, onsemiDigital transistor (NPN, resistors built in)SOT-3636 pinsonsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    onsemi
    Package
    SOT-363
    Pins
    6
    Details
    Dual NPN Bias Resistor Transistors R1 = 10 k  , R2 = 47 k 
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor NSVMUN5214DW1, opens in a new tab
  • PESD15VS2UATSOT-23ESD protection diode, 3 pins, NexperiaESD protection diodeSOT-233 pinsNexperia
    What it is
    ESD protection diode
    Maker
    Nexperia
    Package
    SOT-23
    Pins
    3
    Details
    Double ESD protection diode in SOT23 package
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor PESD15VS2UAT, opens in a new tab
  • RSB12WSOT-416Zener diode, 3 pins, ROHMZener diodeSOT-4163 pinsROHM
    What it is
    Zener diode
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    Transient Voltage Suppressor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

    Datasheetfor RSB12W, opens in a new tab
  • RSB12WFHSOT-416Zener diode, 3 pins, ROHMZener diodeSOT-4163 pinsROHM
    What it is
    Zener diode
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    Transient Voltage Suppressor (AEC-Q101 qualified)
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Zener diode.

    Datasheetfor RSB12WFH, opens in a new tab
  • RSB12WMSOT-416ESD protection diode, 3 pins, ROHMESD protection diodeSOT-4163 pinsROHM
    What it is
    ESD protection diode
    Maker
    ROHM
    Package
    SOT-416
    Pins
    3
    Details
    Transient Voltage Suppressor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor RSB12WM, opens in a new tab
  • RSB12ZMSOT-723ESD protection diode, 3 pins, ROHMESD protection diodeSOT-7233 pinsROHM
    What it is
    ESD protection diode
    Maker
    ROHM
    Package
    SOT-723
    Pins
    3
    Details
    Transient Voltage Suppressor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor RSB12ZM, opens in a new tab
  • S-LMUN5214DW1T1GSOT-363Digital transistor (resistors built in), 6 pins, LRCDigital transistor (resistors built in)SOT-3636 pinsLRC
    What it is
    Digital transistor (resistors built in)
    Maker
    LRC
    Package
    SOT-363
    Pins
    6
    Details
    Digital transistor (bias resistors built in), N+N, IC 100 mA, VCEO 50 V
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor S-LMUN5214DW1T1G, opens in a new tab
  • SDA07T130SOD-523ESD protection diode, 2 pins, LeiditechESD protection diodeSOD-5232 pinsLeiditech
    What it is
    ESD protection diode
    Maker
    Leiditech
    Package
    SOD-523
    Pins
    2
    Details
    ESD protection diode, VRWM 7 V, Cj 160 pF
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor SDA07T130, opens in a new tab
  • SMUN5214DWSOT-363Digital transistor (resistors built in), 6 pins, SeCoSDigital transistor (resistors built in)SOT-3636 pinsSeCoS
    What it is
    Digital transistor (resistors built in)
    Maker
    SeCoS
    Package
    SOT-363
    Pins
    6
    Details
    Digital (resistor-equipped) transistor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor SMUN5214DW, opens in a new tab
  • SMUN5214DW1SOT-363Digital transistor (NPN, resistors built in), 6 pins, onsemiDigital transistor (NPN, resistors built in)SOT-3636 pinsonsemi
    What it is
    Digital transistor (NPN, resistors built in)
    Maker
    onsemi
    Package
    SOT-363
    Pins
    6
    Details
    Dual NPN Bias Resistor Transistors R1 = 10 k  , R2 = 47 k 
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: Digital transistor.

    Datasheetfor SMUN5214DW1, opens in a new tab
  • STZU6.2NSOT-23ESD protection diode, 3 pins, ROHMESD protection diodeSOT-233 pinsROHM
    What it is
    ESD protection diode
    Maker
    ROHM
    Package
    SOT-23
    Pins
    3
    Details
    Transient Voltage Suppressor
    Source
    Manufacturer datasheet

    Is it dead? The meter test is below: TVS or ESD protection diode.

    Datasheetfor STZU6.2N, opens in a new tab
  • 2 more parts have no package on record

Is it dead? One meter test per kind

Parts of the same kind are tested the same way, so each test is here once. Each part above points to its own.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

TVS or ESD protection diode

Diode range, from the protected line to ground, part lifted if you can.

Working, it reads

A one-way part reads about 0.6 to 0.8 V forward and open in reverse. A two-way part reads open both ways. Arrays with several lines read as the datasheet's diagram draws them.

Dead, it reads

  • From the line to ground, the same reading both ways, near 0 V with a continuous beep: shorted.
  • A reading both ways on a one-way part: leaky.
  • A one-way part open both ways: failed open.
On the board
, a line reading shorted to ground can be this part or anything else on that line. Lift it: if the short goes with it, it has failed.
Compare:
The same part on the next line or connector pin is the healthy reading to compare with.
Watch for:
A two-way part reads open both ways when it is good, exactly like one that has failed open. The meter cannot tell them apart; an identical part on the next line can.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Zener diode

Diode range for the forward check, part lifted, red probe on the anode. A bench supply for the Zener voltage.

Working, it reads

About 0.6 to 0.8 V forward and open in reverse on the diode range. Its Zener voltage shows only on a supply: feed it through a resistor that sets about 5 mA, cathode to positive, read quickly, and it should hold near its rated voltage.

Dead, it reads

  • The same reading both ways round, near 0 V with a continuous beep or the same middling value: shorted.
  • Open both ways, forward too: failed open.
  • Holds well off its rated voltage on the supply test: drifted.
  • A soft knee, or a voltage that creeps on the supply test: leaky.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
Watch for:
A meter's diode range stops at about 2 to 3 V, so almost every Zener reads open in reverse on it, good or bad; a 3 V meter may just show a 2.4 or 2.7 V part. Above about 3 V the meter cannot tell a Zener from a plain diode.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

Digital transistor

Ohms range, part lifted. The datasheet gives the built-in resistors: R1 in series with the base, R2 from base to emitter.

Working, it reads

Base to emitter reads about R1 plus R2 either way round, about 20 kΩ on a 10 k and 10 k part, give or take their wide tolerance. Collector to emitter reads open. A part with no R2 reads a junction behind R1 one way instead.

Dead, it reads

  • Collector to emitter the same both ways, near 0 Ω with a continuous beep: shorted.
  • From the base, open or far above R1 plus R2: R1 has failed. Static damage shows here most often.
  • Base to emitter near 0 Ω: failed short.
On the board
this is a first look only: the meter reads every path between those pins, and a short can be a neighbour. Lift one leg before you condemn it.
Compare:
The readings depend on the resistor values, so an identical part elsewhere on the board is the surest reference. Measure it the same way.
Watch for:
On the diode range a good part with 10 kΩ resistors reads open on every pair, so a good part looks dead there. Use the ohms range.

A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.

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