FS26 datasheet(100/156 Pages) NXP

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NXP Semiconductors

FS26

Safety system basis chip with low power for ASIL D/ASIL B

18.4 VCORE: low-voltage buck regulator

The VCORE block is a low-voltage integrated synchronous buck operating in forced PWM mode and using

internal FETs. The output voltage is configurable by OTP in a range from 0.8 V to 3.35 V, and the switching

frequency is 2.25 MHz. Compensation is ensured by internal circuitry.

A dynamic voltage scaling (DVS) feature is configurable by OTP, to control the ramp-up and ramp-down of the

regulator. The passive pull-down resistor is enabled during the ramp down.

The current in the inductor is sensed via the internal FETs. A thermal shutdown is implemented to protect

the internal FETs. When the current in the inductor rises above the ICORE_PEAK threshold configured with the

CORE_ILIM_OTP[1:0] bits, the SPI bit COREOC_I is set. This overcurrent detection does not turn OFF the

VCORE but will induce a duty cycle reduction and therefore an output voltage drop.

During the overcurrent condition, the regulator switching frequency may be divided by 2. The regulator will

be back to its nominal switching frequency when the overcurrent condition is removed. When the lower

CORE_ILIM_OTP[1:0] setting is selected, it is recommended to select LCORE at 1.5 μH or 2.2 μH.

VCORE

VCORE_IN

COUT_CORE

CBOOT

LCORE

CIN_CORE

aaa-045467

Figure 29. VCORE schematic

18.4.1 VCORE electrical characteristics

TA = –40 °C to 125 °C, unless otherwise specified. VSUP_UVH < VSUP < 36 V, VPRE_PWM + VPRE_HDR < VSUP_PWR < 36 V, unless otherwise

specified. All voltages are referenced to ground.

Symbol

Description

Min

Typ

Max

Unit

Static electrical characteristics

VCORE_IN

Input voltage range

2.5

—

6.35

VCORE

Output voltage (OTP configuration, 10 mV step)

0.8

—

3.35

Output current capability

ICORE

FS260x and FS261x

FS262x and FS263x

—

0.8

1.65

Output voltage accuracy

VCORE_ACC

IOUT ≤ 1.5 A

1.5 A < IOUT ≤ 1.65 A

-2

-2.5

—

2.5

Minimum headroom (VCORE_IN – VCORE)

VCORE_HDR

ICORE ≤ 800 mA

ICORE ≤ 1.5 A

ICORE ≤ 1.65 A

400

800

900

—

Inductor peak current limitation for FS260x and FS261x

ICORE_PEAK_0A8

CORE_ILIM_OTP[1:0] = 00

0.9

1.4

1.9

Table 106. VCORE electrical characteristics

FS26_SDS

All information provided in this document is subject to legal disclaimers.

Product short data sheet

Rev. 6.0 — 12 December 2025

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