SMD code 55-
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.
105 parts are printed 55-
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.
S-LEDZ16BT1GSOD-523Zener diode, 2 pins, LRCZener diodeSOD-5232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-523
- Pins
- 2
- Details
- Zener diode, VZ Min 15.85 V, VZ Nom 16.2 V, VZ Max 16.51 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
S-LUDZS16BT1GSOD-323Zener diode, 2 pins, LRCZener diodeSOD-3232 pinsLRC
- What it is
- Zener diode
- Maker
- LRC
- Package
- SOD-323
- Pins
- 2
- Details
- Zener diode, VZ Min 15.85 V, VZ Nom 16.2 V, VZ Max 16.51 V
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
SBZX584B3V9-CSOD-523Zener diode, 2 pins, SeCoSZener diodeSOD-5232 pinsSeCoS
- What it is
- Zener diode
- Maker
- SeCoS
- Package
- SOD-523
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
TBZX584B3V9SOD-523Zener diode, 2 pins, Galaxy MicroelectronicsZener diodeSOD-5232 pinsGalaxy Microelectronics
- What it is
- Zener diode
- Maker
- Galaxy Microelectronics
- Package
- SOD-523
- Pins
- 2
- Details
- 3.9V, 150mW, Surface Mount Zener Diodes
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
UDZ16BSOD-323Zener diode, 2 pins, Formosa MicrosemiZener diodeSOD-3232 pinsFormosa Microsemi
- What it is
- Zener diode
- Maker
- Formosa Microsemi
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
UDZV16BSOD-323Zener diode, 2 pins, ROHMZener diodeSOD-3232 pinsROHM
- What it is
- Zener diode
- Maker
- ROHM
- Package
- SOD-323
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
UDZVFH16BSOD-323Zener diode, 2 pins, ROHMZener diodeSOD-3232 pinsROHM
- What it is
- Zener diode
- Maker
- ROHM
- Package
- SOD-323
- Pins
- 2
- Details
- Zener Diode (AEC-Q101 qualified)
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
VDZ16BSOD-723Zener diode, 2 pins, YFWZener diodeSOD-7232 pinsYFW
- What it is
- Zener diode
- Maker
- YFW
- Package
- SOD-723
- Pins
- 2
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Zener diode.
EIA-96:550603Precision resistor (EIA-96 code), 2 pinsPrecision resistor (EIA-96 code)06032 pinsNot recorded
- What it is
- Precision resistor (EIA-96 code)
- Maker
- Not recorded
- Package
- 0603
- Pins
- 2
- Details
- EIA-96 precision chip resistor, code 55 stands for 365 in the E96 table; the printed mark adds a multiplier letter (55A = 365 Ohm, 55B = 3.65 kOhm)
- Source
- Added by hand from a published table
Is it dead? The meter test is below: Resistor.
6 more parts have no package on record
SAV-551+RF amplifier (MMIC), Mini-CircuitsRF amplifier (MMIC)Not recordedNot recordedMini-Circuits
- What it is
- RF amplifier (MMIC)
- Maker
- Mini-Circuits
- Package
- Not recorded
- Pins
- Not recorded
- Details
- MMIC amplifier, 0.045-6 GHz
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
SGM05CB1A4XXEI2G2 pins, SG MicroNot recordedNot recorded2 pinsSG Micro
- What it is
- Not recorded
- Maker
- SG Micro
- Package
- Not recorded
- Pins
- 2
- Details
- Low Capacitance 1-Channel ESD Protection
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: TVS or ESD protection diode.
SGM892B-1.6XUDH4GVoltage supervisor, 4 pins, SG MicroVoltage supervisorNot recorded4 pinsSG Micro
- What it is
- Voltage supervisor
- Maker
- SG Micro
- Package
- Not recorded
- Pins
- 4
- Details
- Standard CMOS Voltage Detector ICs
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: Integrated circuit.
TAV1-551+RF amplifier (MMIC), Mini-CircuitsRF amplifier (MMIC)Not recordedNot recordedMini-Circuits
- What it is
- RF amplifier (MMIC)
- Maker
- Mini-Circuits
- Package
- Not recorded
- Pins
- Not recorded
- Details
- MMIC amplifier, 0.045-6 GHz
- Source
- Manufacturer datasheet
Is it dead? The meter test is below: RF amplifier.
74AUP1Z125GFNXPNot recordedNot recordedNot recordedNXP
- What it is
- Not recorded
- Maker
- NXP
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: X-tal driver with enable and internal resistor
- Source
- Published code list
Is it dead? The meter test is below: Resistor.
74AUP1Z125GMNXPNot recordedNot recordedNot recordedNXP
- What it is
- Not recorded
- Maker
- NXP
- Package
- Not recorded
- Pins
- Not recorded
- Details
- CMOS logic IC: X-tal driver with enable and internal resistor
- Source
- Published code list
Is it dead? The meter test is below: Resistor.
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.
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.
RF amplifier
Voltage, board powered, on the output pin that the bias resistor or choke feeds.
Working, it reads
The output pin sits at the device voltage the datasheet gives, a few volts, below the supply.
Dead, it reads
- Output pin at 0 V, or near 0 Ω to ground with the power off: shorted inside.
- Output pin at the full supply voltage: open inside, no current flowing.
- On the board:
- Measured on the board with power on; the bias network is part of the reading.
- Compare:
- If an identical part sits elsewhere on the board, measure it the same way: that is what this one should read.
- Watch for:
- The figures depend on the part and its bias resistor. The datasheet gives both.
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.
Integrated circuit
Voltage with the board powered; ohms from each pin to ground with it off.
Working, it reads
Supply pin at its voltage and the output doing what the datasheet says. Readings between pins depend on the part.
Dead, it reads
- A pin near 0 Ω to ground or to the supply pin where an identical part does not read that: failed short.
- Supply present, output stuck: failed, or its load has.
- On the board:
- A pin shorted to ground on the board can be anything on that net. Lift the pin to be sure.
- Compare:
- The surest reference is the same IC on a working board, measured pin by pin.
- Watch for:
- Its protection diodes can read like junctions between pins, even like a transistor. That proves nothing either way.
A dead part still carries its marking. A short or an open says it has failed, not that it is a different part.
Resistor
Ohms range, across it, power off.
Working, it reads
Its marked value, within tolerance. On the board it reads the same or lower, because everything around it sits in parallel.
Dead, it reads
- Open: burnt, cracked, or eaten through by sulphur. The commonest failure.
- Well above its marked value: drifted high.
- On the board, clearly higher than its marked value: it has failed, since the board can only pull a reading down.
- On the board:
- A reading lower than marked on the board proves nothing; lift one end. A reading higher than marked is a fault even on the board.
- Compare:
- The same position on another channel usually carries the same value, and so does the matching part on another board.
- Watch for:
- A burnt resistor usually means the part it feeds pulled too much. Find that before fitting a new one, or it burns too. The marking, not the reading, says what to fit.
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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