MAX8775 Просмотр технического описания (PDF) - Maxim Integrated

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MAX8775

Dual and Combinable Graphics Core Controller for Notebook Computers

Maxim Integrated 

Dual and Combinable Graphics Core

Controller for Notebook Computers

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, VIN = 12V, SKIP_ = 0, ON_ = VCC = 5V, separate mode, TA = -40°C to +85°C, unless otherwise noted.) (Note 6)

PARAMETER

FAULT DETECTION

OVP_ Adjust Range

Output Overvoltage Trip Threshold

Output Undervoltage Protection

Trip Threshold

PGOOD_ Lower Trip Threshold

PGOOD_ Output Low Voltage

Current-Balance Fault

Comparator Thresholds

GATE DRIVERS

DH_ Gate Driver On-Resistance

DL_ Gate Driver On-Resistance

(Note 4)

INPUTS AND OUTPUTS

Logic Input-High Threshold

SYMBOL

CONDITIONS

VOVP_

Rising edge measured at CSL_,

with respect to OVP_ set voltage

Falling edge measured at CSL_,

with respect to error comparator threshold

Falling edge measured at CSL_

with respect to error comparator threshold,

hysteresis = 1%

ISINK = 4mA

V(CCI2, REF),

0.5V ≤ VFB ≤ 2.5V

Lower threshold,

0.84VREF

Upper threshold,

1.2VREF

RDH BST_ - LX_ forced to 5V (Note 4)

DL_, high state

RDL

DL_, low state

ON1, ON2, DTRANS, SKIP1, SKIP2,

hysteresis = 225mV

MIN TYP MAX UNITS

0.5

2.5

V

180

220

mV

275

325

mV

-180

2.0

2.9

-120 mV

0.4

V

2.2

mV

3.1

5

Ω

5

Ω

3

1.2

2.2

V

Note 1: When the inductor is in continuous conduction, the output voltage has a DC regulation level lower than the error comparator

threshold by 50% of the ripple. In discontinuous conduction, the output voltage has a DC regulation level higher than the

error comparator threshold by 50% of the ripple.

Note 2: Operation below 0.5V but above the REFOK threshold is allowed, but the accuracy is not guaranteed.

Note 3: The MAX8775 cannot operate over all combinations of frequency, input voltage (VIN), and output voltage. For large input-to-

output differentials and high switching-frequency settings, the required on-time might be too short to maintain the regulation

specifications. Under these conditions, a lower operating frequency must be selected. The minimum on-time must be

greater than 150ns, regardless of the selected switching frequency. On-time and off-time specifications are measured from

the 50% point to the 50% point at the DH_ pin with LX_ = GND, VBST_ = 5V, and a 250pF capacitor connected from DH_ to

LX_. Actual in-circuit times may differ due to MOSFET switching speeds.

Note 4: Specifications are guaranteed by design, not production tested.

Note 5: Production testing limitations due to package handling require relaxed maximum on-resistance specifications for the

thin QFN package.

Note 6: Specifications to TA = -40°C to +85°C are guaranteed by design, not production tested.

6 _______________________________________________________________________________________

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