How many pins does an HDMI connector have?

Types A (standard), C (mini) and D (micro) have 19, with the same signals but different numbering. Type B, with 29 pins and a dual TMDS link, is defined in HDMI 1.3 but very rarely seen.

Is the micro HDMI pinout the same as standard HDMI?

No. The signals are identical, but micro HDMI (Type D) numbers them differently: HPD on pin 1, +5 V on pin 19, data pair 2 on pins 3 to 5. Mini HDMI (Type C) also differs from Type A. Always use the table for the exact type.

How much current can be drawn from the HDMI +5 V pin?

Very little. The source guarantees 55 mA minimum and the display must not exceed 50 mA. This +5 V powers the EDID and detection, not a device: an adapter or dongle that needs more must have its own supply.

What is pin 14 (Utility) for on HDMI Type A?

It was reserved up to HDMI 1.3. Since HDMI 1.4 it carries HEAC+; with HPD as HEAC−, it forms the pair for the Ethernet channel (HEC) and the Audio Return Channel (ARC). Equipment that uses neither leaves it unconnected.

What impedance for the TMDS pairs?

100 Ω differential. The specification sets that value for the connector, the cable and the display termination; the board routing must hold it all the way to the connector.

Pinout

HDMI pinout: Type A, mini HDMI and micro HDMI

HDMI Type A, mini (Type C) and micro (Type D) connectors all have 19 pins and carry the same signals: three TMDS data pairs and one clock pair with their shields, the DDC bus for EDID, CEC, +5 V power and hot plug detect (HPD). Only the pin numbering changes from one type to the next.

By Hugues Orgitello · Updated October 25, 2026 ·

HDMI Type A (standard), 19 pins

Signal names from the HDMI specification (Table 4-1). Direction is seen from the source (player, board, SoC); it reverses on the display side. Odd pins sit in the row on the wide side, even pins half a pitch over in the row below, 0.5 mm pitch.

Pin	Signal	Dir.	Description
1	TMDS Data2+	Out	TMDS data pair 2, positive (Differential pair)
2	TMDS Data2 Shield		Pair 2 shield, tied to ground (Shield / earth)
3	TMDS Data2-	Out	TMDS data pair 2, negative (Differential pair)
4	TMDS Data1+	Out	TMDS data pair 1, positive (Differential pair)
5	TMDS Data1 Shield		Pair 1 shield, tied to ground (Shield / earth)
6	TMDS Data1-	Out	TMDS data pair 1, negative (Differential pair)
7	TMDS Data0+	Out	TMDS data pair 0, positive (Differential pair)
8	TMDS Data0 Shield		Pair 0 shield, tied to ground (Shield / earth)
9	TMDS Data0-	Out	TMDS data pair 0, negative (Differential pair)
10	TMDS Clock+	Out	TMDS clock pair, positive (Differential pair)
11	TMDS Clock Shield		Clock pair shield, tied to ground (Shield / earth)
12	TMDS Clock-	Out	TMDS clock pair, negative (Differential pair)
13	CEC	I/O	Consumer Electronics Control: single-wire control bus shared by every device (Signal)
14	Utility / HEAC+	I/O	Reserved in HDMI 1.3; since HDMI 1.4, HEAC+ (Ethernet channel and Audio Return Channel). Leave unconnected if unused (Signal)
15	SCL	Out	DDC clock (I²C): reads the display’s EDID (Signal)
16	SDA	I/O	DDC data (I²C) (Signal)
17	DDC/CEC Ground		Reference ground for DDC, CEC, HPD and the +5 V return (Ground)
18	+5V Power	Out	+5 V supplied by the source: 55 mA minimum, the sink draws no more than 50 mA (Power)
19	Hot Plug Detect / HEAC-	In	Hot plug detect, driven high by the display once its EDID is readable; HEAC− since HDMI 1.4 (Signal)

Mini HDMI (Type C), 19 pins

HDMI specification, Table 4-3. The 19 contacts form a single row at 0.4 mm pitch, under the tongue. Compared with Type A, each shield moves ahead of its positive line, and CEC, DDC/CEC ground and the Utility pin change places.

Pin	Signal	Dir.	Type A pin	Description
1	TMDS Data2 Shield		2	Pair 2 shield, tied to ground (Shield / earth)
2	TMDS Data2+	Out	1	TMDS data pair 2, positive (Differential pair)
3	TMDS Data2-	Out	3	TMDS data pair 2, negative (Differential pair)
4	TMDS Data1 Shield		5	Pair 1 shield, tied to ground (Shield / earth)
5	TMDS Data1+	Out	4	TMDS data pair 1, positive (Differential pair)
6	TMDS Data1-	Out	6	TMDS data pair 1, negative (Differential pair)
7	TMDS Data0 Shield		8	Pair 0 shield, tied to ground (Shield / earth)
8	TMDS Data0+	Out	7	TMDS data pair 0, positive (Differential pair)
9	TMDS Data0-	Out	9	TMDS data pair 0, negative (Differential pair)
10	TMDS Clock Shield		11	Clock pair shield, tied to ground (Shield / earth)
11	TMDS Clock+	Out	10	TMDS clock pair, positive (Differential pair)
12	TMDS Clock-	Out	12	TMDS clock pair, negative (Differential pair)
13	DDC/CEC Ground		17	Reference ground for DDC, CEC, HPD and the +5 V return (Ground)
14	CEC	I/O	13	Consumer Electronics Control: single-wire control bus shared by every device (Signal)
15	SCL	Out	15	DDC clock (I²C): reads the display’s EDID (Signal)
16	SDA	I/O	16	DDC data (I²C) (Signal)
17	Utility / HEAC+	I/O	14	Reserved in HDMI 1.3; since HDMI 1.4, HEAC+ (Ethernet channel and Audio Return Channel). Leave unconnected if unused (Signal)
18	+5V Power	Out	18	+5 V supplied by the source: 55 mA minimum, the sink draws no more than 50 mA (Power)
19	Hot Plug Detect / HEAC-	In	19	Hot plug detect, driven high by the display once its EDID is readable; HEAC− since HDMI 1.4 (Signal)

Micro HDMI (Type D), 19 pins

Type D, introduced with HDMI 1.4. Completely different numbering: HPD moves to pin 1 and +5 V to pin 19. Two rows at 0.4 mm pitch, odd pins on top, even pins below, as on Type A.

Pin	Signal	Dir.	Type A pin	Description
1	Hot Plug Detect / HEAC-	In	19	Hot plug detect, driven high by the display once its EDID is readable; HEAC− since HDMI 1.4 (Signal)
2	Utility / HEAC+	I/O	14	Reserved in HDMI 1.3; since HDMI 1.4, HEAC+ (Ethernet channel and Audio Return Channel). Leave unconnected if unused (Signal)
3	TMDS Data2+	Out	1	TMDS data pair 2, positive (Differential pair)
4	TMDS Data2 Shield		2	Pair 2 shield, tied to ground (Shield / earth)
5	TMDS Data2-	Out	3	TMDS data pair 2, negative (Differential pair)
6	TMDS Data1+	Out	4	TMDS data pair 1, positive (Differential pair)
7	TMDS Data1 Shield		5	Pair 1 shield, tied to ground (Shield / earth)
8	TMDS Data1-	Out	6	TMDS data pair 1, negative (Differential pair)
9	TMDS Data0+	Out	7	TMDS data pair 0, positive (Differential pair)
10	TMDS Data0 Shield		8	Pair 0 shield, tied to ground (Shield / earth)
11	TMDS Data0-	Out	9	TMDS data pair 0, negative (Differential pair)
12	TMDS Clock+	Out	10	TMDS clock pair, positive (Differential pair)
13	TMDS Clock Shield		11	Clock pair shield, tied to ground (Shield / earth)
14	TMDS Clock-	Out	12	TMDS clock pair, negative (Differential pair)
15	CEC	I/O	13	Consumer Electronics Control: single-wire control bus shared by every device (Signal)
16	DDC/CEC Ground		17	Reference ground for DDC, CEC, HPD and the +5 V return (Ground)
17	SCL	Out	15	DDC clock (I²C): reads the display’s EDID (Signal)
18	SDA	I/O	16	DDC data (I²C) (Signal)
19	+5V Power	Out	18	+5 V supplied by the source: 55 mA minimum, the sink draws no more than 50 mA (Power)

An interface to design?

An HDMI output to bring up on a SoC, a display that will not read EDID, a board to take through EMC? We design HDMI 2.0 boards and measure eye diagrams in our lab on a Tektronix oscilloscope running TekExpress.

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Same signals, three numberings

All three connectors carry exactly the same 19 signals; a passive adapter wires them one to one. What changes is the pin number. Mini HDMI keeps the Type A order but puts each shield ahead of its positive line. Micro HDMI starts over: HPD on 1, Utility on 2, the TMDS pairs on 3 to 14, then CEC, ground, SCL, SDA and +5 V.

The “Type A pin” column in the mini and micro tables gives the mapping. It is there to wire an adapter, but above all to check a schematic symbol: a library that copies the Type A numbering onto a micro HDMI footprint produces a board where nothing works.

HDMI Type A, Type C (mini) and Type D (micro) receptacle openings, at the same scale. The rectangles give the bounding size: the real shape is a trapezoid, wide side up. Inside dimensions of the shell. Type A: HDMI 1.3 specification, Figure 4-1 (14 +0.05/−0.04 × 4.55 +0.05/−0.04 mm). Type C: Figure 4-8 (10.5 +0.04/−0.03 × 2.5 mm). Type D, not in version 1.3: Wurth WR-COM drawing 685119248123 (5.9 ± 0.20 × 2.3 ± 0.15 mm).

+5 V, DDC, HPD and CEC: the values in the specification

+5 V. The source supplies at least 55 mA, between 4.8 and 5.3 V, and must limit the current to 0.5 A at most. The display draws no more than 50 mA from it, and only 10 mA when it is powered itself: this +5 V is mainly there to read the EDID of a display that is off. It returns through DDC/CEC ground.

DDC. It is a standard-mode I²C bus referenced to 5 V. The source pulls SCL and SDA up to +5 V through 1.5 to 2.0 kΩ; the display adds 47 kΩ on SCL. The allowed capacitance is 50 pF at the source and at the display, 700 pF for the cable.

HPD. The display drives it high (2.4 to 5.3 V, 1 kΩ ± 20 % output resistance) only once it sees +5 V and its EDID is readable. The source reads it high above 2.0 V, low below 0.8 V. Many displays simply tie HPD to +5 V through 1 kΩ, so the specification advises a pull-down on the source side to tell “unplugged” from “high”.

CEC. A single-wire line shared by every device in the setup, pulled up through 27 kΩ ± 5 % in each device, with a high level between 2.5 and 3.63 V. That pull-up must disconnect when the device is off, for example through a series diode, or a powered-down device holds the bus.

Routing the TMDS pairs

Route each TMDS pair at 100 Ω differential, the value the specification sets for the connector and the cable. Keep both lines of a pair the same length, avoid needless layer changes, and run a continuous ground plane underneath. Skew between pairs matters less, since the receiver realigns the channels, but it is still bounded.

The Shield pins are grounds: tie each one to ground at the connector, with its own via. They frame the pairs in the connector and in the cable; leaving them floating degrades impedance and radiated emissions. Since HDMI 2.1, in FRL mode, the clock pair becomes a fourth data lane: route it with the same care as the other three.

The most common design mistakes

A micro or mini footprint wired with Type A numbering. The most expensive mistake, because no soldering iron can fix it. Check the symbol pin by pin against the right type’s table before releasing the board.

DDC wired straight to a 3.3 V SoC. The bus is referenced to +5 V and the cable can add up to 700 pF. An I²C level translator, or an HDMI companion chip that includes one, protects the SoC pins and keeps rise times in spec.

+5 V without current limiting. The specification requires protection at 0.5 A at most on the source side. A short in a cable or an adapter must not take down the board’s 5 V rail.

HPD floating on the source side. Without a pull-down, an open HPD input can read high and the source tries to read an EDID that is not there. On the display side, only raise HPD once +5 V is present and the EDID is ready.

No ESD protection at the connector. HDMI pins are exposed at every plug-in. Put the TVS diodes as close to the connector as possible, with very low capacitance on the TMDS pairs so the 100 Ω impedance survives.

Frequently asked questions

FAQ

How many pins does an HDMI connector have?: Types A (standard), C (mini) and D (micro) have 19, with the same signals but different numbering. Type B, with 29 pins and a dual TMDS link, is defined in HDMI 1.3 but very rarely seen.
Is the micro HDMI pinout the same as standard HDMI?: No. The signals are identical, but micro HDMI (Type D) numbers them differently: HPD on pin 1, +5 V on pin 19, data pair 2 on pins 3 to 5. Mini HDMI (Type C) also differs from Type A. Always use the table for the exact type.
How much current can be drawn from the HDMI +5 V pin?: Very little. The source guarantees 55 mA minimum and the display must not exceed 50 mA. This +5 V powers the EDID and detection, not a device: an adapter or dongle that needs more must have its own supply.
What is pin 14 (Utility) for on HDMI Type A?: It was reserved up to HDMI 1.3. Since HDMI 1.4 it carries HEAC+; with HPD as HEAC−, it forms the pair for the Ethernet channel (HEC) and the Audio Return Channel (ARC). Equipment that uses neither leaves it unconnected.
What impedance for the TMDS pairs?: 100 Ω differential. The specification sets that value for the connector, the cable and the display termination; the board routing must hold it all the way to the connector.

Sources

Tables built from these documents and cross-checked against manufacturer datasheets. Always check the datasheet of the connector you actually use: some manufacturers number differently.