MCP1643

DS20005208B-page 4

 2013-2023 Microchip Technology Inc. and its subsidiaries

Minimum Duty Cycle

DCMIN

—5

—

%

Note 3

Switching Frequency

fSW

0.85

1.0

1.15

MHz

—

EN Input Logic High

VIH

75

—

—

% of VIN ILED=25mA

EN Input Logic Low

VIL

——

20

% of VIN ILED =25mA

EN Input Leakage Current

IENLK

—0.9

—

µA

VEN =1.2V

Soft Start Time

tSS

—240

—

µs

EN Low-to-High,

90% of VOUT;

ILED =25mA, (Note 3)

—270

—

µs

EN Low-to-High,

90% of VOUT;

ILED =300 mA, (Note 3)

Thermal Shutdown

Die Temperature

TSD

—150

—

CILED=25mA

Die Temperature

Hysteresis

TSDHYS

—25

—

C—

DC CHARACTERISTICS (CONTINUED)

Electrical Characteristics: Unless otherwise indicated, VIN = EN = 1.2V, COUT =20µF, CIN =10µF, L = 4.7µH,

ILED =25mA, TA =+25°C. Boldface specifications apply over the TA range of -40°C to +85°C.

Parameters

Sym

Min

Typ

Max

Units

Conditions

Note 1: For VIN <VOUT, ILED remains in regulation up to VIN =VLED minus a headroom @ LED typical VF and IF.

2: VOUT completely discharged. If the output capacitor remains partially charged, the device will start-up at

the minimum possible voltage.

3: Determined by characterization, not production tested.

TEMPERATURE SPECIFICATIONS

Electrical Characteristics: Unless otherwise indicated, VIN = EN = 1.2V, COUT =20µF, CIN =10µF, L = 4.7µH,

ILED =25mA, TA =+25°C. Boldface specifications apply over the TA range of -40°C to +85°C.

Parameters

Sym

Min

Typ

Max

Units

Conditions

Temperature Ranges

Operating Ambient Temperature Range

TA

-40

—

+85

°C

Steady State

Storage Temperature Range

TA

-65

—

+150

°C

—

Maximum Junction Temperature

TJ

—

—

+150

°C

Transient

Package Thermal Resistances

Thermal Resistance, 8-Lead,

2 mm x 3 mm DFN

JA

—68

—

°C/W

—

Thermal Resistance, 8-Lead, MSOP

JA

—211

—

°C/W

—