ISL1208IB8Z-TK from RENESAS, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	X1	input	Input of the internal inverting amplifier for the 32.768kHz crystal oscillator. Connects to one pin of an external 32.768kHz quartz crystal, or can be driven directly from a 32.768kHz source.
2	X2	output	Output of the internal inverting amplifier for the 32.768kHz crystal oscillator. Connects to the other pin of the external 32.768kHz quartz crystal. Leave floating when X1 is driven by an external clock source.
3	VBAT	power_in	Backup supply input (1.8V to 5.5V). Supplies power to the device when VDD fails (below VTRIP ~2.2V typ). Tie to ground if unused. Typical battery supply current 400nA.
4	GND	power_in	Device ground reference.
5	SDA	bidirectional	I2C Serial Data line. Bidirectional open-drain pin used to transfer serial data into and out of the device. May be wire-OR'ed with other open-drain/open-collector outputs. Requires an external pull-up resistor (≥1kΩ).
6	SCL	input	I2C Serial Clock input used to clock all serial data into and out of the device. Supports up to 400kHz data transfer rate. Requires an external pull-up resistor.
7	IRQ/FOUT	output	Multi-function open-drain output pin, configurable via the configuration register as either an active-low alarm interrupt (IRQ) or as a selectable frequency output (FOUT) with 15 selectable frequencies. VOL = 0.4V max at IOL = 3mA (VDD=5V).
8	VDD	power_in	Main power supply input, 2.7V to 5.5V. Typical supply current 2μA (VDD=5V, I2C idle) or 40μA when I2C is active.

Key specifications

Parameter	Value
Manufacturer	RENESAS
Package	SOIC-8
Category	RTC
Pins	8

Ordering variants

Same part, different packaging or reel option.

ISL1208IB8Z-TK
ISL1208IB8Z-TKIB8-TK
ISL1208IB8Z-TKIU8
ISL1208IB8Z-TKIU8-TK
ISL1208IB8Z-TKIU8Z
ISL1208IB8Z-TKIU8Z-TK

CAD (KiCad official)

Symbol: ISL1208IB8Z-TK
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`isl1208ib8z-tk.step`	122 KB	You want the bare part, or you mark your own boards.
`isl1208ib8z-tk-etched.step`	2.7 MB	You want the part with `ISL1208IB8Z-TK` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 657 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: RENESAS datasheet (21 pp, sha256 9e849503d6495df5, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF