Step-Down Controllers with

Synchronous Rectifier for CPU Power

4

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ELECTRICAL CHARACTERISTICS (continued)

Note 3: All -40°C to +85°C specifications above are guaranteed by design.

External resistor divider

0mV < (CSH - CSL) < 80mV, FB = VL, 4.5V < V+ < 30V,

includes line and load regulation

0mV < (CSH - CSL) < 80mV, FB = VL, 6V < V+ < 30V,

includes line and load regulation

CONDITIONS

V

REF

6.0

Nominal Adjustable Output

Voltage Range

V

3.10

3.35

3.56

3.3V Output Voltage (CSL)

V

5.0

30

Input Supply Range

V

4.70

5.10

5.40

5V Output Voltage (CSL)

UNITS

MIN

TYP

MAX

PARAMETER

CSH - CSL, negative

(CSH-CSL) = 0V

6V < V+ < 30V

CSH - CSL, positive

-40

-100

-160

Current-Limit Voltage

V

2.40

2.60

Feedback Voltage

%/V

0.04

0.06

Line Regulation

mV

70

130

FB = CSH = CSL = 6V, VL switched over to CSL

SHDN = 0V, V+ = 30V, CSL = 0V or 6V

Rising edge, hysteresis = 25mV

No external load (Note 1)

µA

110

V+ Off-State Leakage Current

µA

110

V+ Shutdown Current

V

Rising edge, hysteresis = 15mV

4.2

4.7

VL/CSL Switchover Voltage

V

2.43

2.505

2.57

Reference Output Voltage

Falling edge, hysteresis = 15mV (MAX796)

Falling edge, hysteresis = 20mV (MAX799)

mV

50

Reference Load Regulation

V

3.75

4.05

VL Fault Lockout Voltage

V

4.7

5.3

VL Output Voltage

2.40

2.60

V

-0.08

0.08

SECFB Regulation Setpoint

SYNC = REF

SYNC = 0V or 5V

89

91

kHz

210

320

Oscillator Sync Range

kHz

SYNC = REF

120

150

180

Oscillator Frequency

ns

250

SYNC High Pulse Width

ns

250

SYNC Low Pulse Width

250

300

350

mW

4.8

8.4

Quiescent Power Consumption

High or low, BST - LX = 4.5V

High or low

SYNC = 0V or 5V

Ω

7

DH On-Resistance

Ω

7

DL On-Resistance

%

93

96

Maximum Duty Cycle

+3.3V and +5V STEP-DOWN CONTROLLERS

FLYBACK/PWM CONTROLLER

INTERNAL REGULATOR AND REFERENCE

OSCILLATOR AND INPUTS/OUTPUTS