Drives the primary of a small center-tapped transformer in push-pull to build an isolated DC-DC supply, the power half of an isolated interface next to a digital isolator. Two integrated switches (D1, D2) alternate at a fixed frequency set on-chip, delivering up to 1 A, and slew-rate control plus spread-spectrum clocking keep EMI low. An EN pin gates it and a CLK pin can synchronize several units. It turns a 5 V rail plus a transformer into an isolated output cleanly.

Pinout

Pin	Name	Type	Function
1	D1	output	Open-drain output of the first power MOSFET (1 A, R_ON 0.25 Ω max at 4.5 V). Connects to one outer terminal of the center-tapped transformer primary. Traces should be kept short due to large switching currents.
2	VCC	power_in	Device supply pin, 2.25 V to 5.5 V. Bypass with a 4.7 µF or greater low-ESR capacitor. Internal UVLO (positive-going 2.25 V, negative-going 1.7 V) turns both outputs off when VCC ≤ 2.25 V.
3	D2	output	Open-drain output of the second power MOSFET (1 A, R_ON 0.25 Ω max at 4.5 V). Connects to the other outer terminal of the center-tapped transformer primary. Traces should be kept short due to large switching currents.
4	GND	power_in	Ground reference; connected to the source of the power MOSFET switches via an internal sense circuit. Must be tied to a low-inductance quality ground plane because large switching currents flow through it.
5	EN	input	Enable input. Logic high (≥0.7·VCC) enables the device; grounding or leaving floating disables all internal circuitry (I_DIS ≈ 0.1 µA). Tie directly to VCC if unused. Absolute max −0.5 V to VCC + 0.5 V.
6	CLK	input	External clock input for synchronizing switching (100 kHz to 1600 kHz on SN6505B). Internally pulled down to GND; if no valid clock is detected the device automatically switches to its internal 420 kHz oscillator. Absolute max −0.5 V to VCC + 0.5 V.

Key specifications

Parameter	Value
Type	Push-pull transformer driver
Switch current	1 A
Switching	Fixed frequency (on-chip), spread-spectrum
EMI control	Slew-rate limited outputs
Enable	EN pin
Sync	CLK pin
Supply	2.25-5 V
Package	SOT-23-6

Ordering variants

Same part, different packaging or reel option.

SN6505BDBVR (SOT-23-6, 420 kHz)
SN6505ADBVR (160 kHz)

CAD (KiCad official)

Symbol: Power_Management:SN6505BDBV (KiCad official)
Footprint: Package_TO_SOT_SMD:SOT-23-6
3D model: SOT-23-6 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Texas Instruments datasheet (43 pp, sha256 dfc57cb042218cb6, 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