MAX668_12 datasheet(2/18 Pages) MAXIM

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1.8V to 28V Input, PWM Step-Up

Controllers in µMAX

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ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC = VLDO = +5V, ROSC = 200kΩ, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)

VCC to GND ..........................................................-0.3V to +30V

PGND to GND....................................................................±0.3V

SYNC/SHDN to GND .............................................-0.3V to +30V

EXT, REF to GND.....................................-0.3V to (VLDO + 0.3V)

LDO, FREQ, FB, CS+ to GND ................................ -0.3V to +6V

LDO Output Current...........................................-1mA to +20mA

REF Output Current..............................................-1mA to +1mA

LDO Short Circuit to GND .........................................Momentary

REF Short Circuit to GND ..........................................Continuous

Continuous Power Dissipation (TA = +70°C)

10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature ......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering,10sec) ..............................+300°C

Soldering Temperature (Reflow) ......................................+300°C

Lead(Pb)-Free Packages..............................................+260°C

Packages Containing Lead(Pb)....................................+240°C

100

115

425

500

575

225

250

275

ROSC = 200kΩ ±1%

Oscillator Frequency

Oscillator

1.0

1.1

1.2

Rising edge, 1% hysteresis

REF Undervoltage Lockout Threshold

-2

-10

REF load = 0 to 50µA

REF Load Regulation

1.225

1.250

1.275

No load, CREF = 0.22µF

REF Output Voltage

2.40

2.50

2.60

Sensed at LDO, falling edge,

hysteresis = 1%, MAX668 only

Undervoltage Lockout Threshold

2.65

5.50

≤ VCC ≤ 28V

(includes LDO dropout)

4.50

5.00

5.50

LDO Output Voltage

Reference and LDO Regulators

328

MAX668

PWM Controller

Input Voltage Range, VCC

3.5

SYNC/SHDN = GND, VCC = 28V

Shutdown Supply Current (VCC)

220

350

VFB = 1.30V, VCC = 3V to 28V

VCC Supply Current (Note 1)

0.2

CS+ forced to GND

CS+ Input Current

515

Idle Mode Current-Sense Threshold

2.7

5.5

Input Voltage Range with VCC Tied to LDO

1.225

1.250

1.275

FB Threshold

VFB = 1.30V

FB Input Current

100

115

Current Limit Threshold

MIN

TYP

MAX

CONDITIONS

PARAMETER

kHz

µA

UNITS

MAX669

1.8

LDO load =

∞ to 400Ω

≤ VCC ≤ 28V

(includes LDO dropout)

ROSC = 500kΩ ±1%

ROSC = 100kΩ ±1%

0.013

Typically 0.013% per mV on CS+;

VCS+ range is 0 to 100mV for 0 to full

load current.

FB Threshold Load Regulation

%/mV

0.012

Typically 0.012% per % duty factor on

EXT; EXT duty factor for a step-up is:

100% (1 – VIN/VOUT)

FB Threshold Line Regulation

%/%

REFERENCE AND LDO REGULATORS

OSCILLATOR

PWM CONTROLLER

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