LM2594 Просмотр технического описания (PDF) - ON Semiconductor

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производитель

LM2594

0.5 A, Step-Down Switching Regulator

ON Semiconductor 

LM2594

SYSTEM PARAMETERS

ELECTRICAL CHARACTERISTICS Specifications with standard type face are for TJ = 25°C, and those with boldface type apply

over full Operating Temperature Range −40°C to +125°C

Characteristics

Symbol

Min

Typ

Max

Unit

LM2594 (Note 1, Test Circuit Figure 16)

Feedback Voltage (Vin = 12 V, ILoad = 0.1 A, Vout = 5.0 V, )

VFB_nom

1.23

V

Feedback Voltage (8.0 V ≤ Vin ≤ 40 V, 0.1 A ≤ ILoad ≤ 0.5 A, Vout = 5.0 V)

VFB

1.193

1.18

1.267

V

1.28

Efficiency (Vin = 12 V, ILoad = 0.5 A, Vout = 5.0 V)

Characteristics

η

−

80

%

Symbol

Min

Typ

Max

Unit

Feedback Bias Current (Vout = 5.0 V)

Ib

25

100

nA

200

Oscillator Frequency (Note 2)

fosc

135

150

165

kHz

120

180

Saturation Voltage (Iout = 0.5 A, Notes 3 and 4)

Vsat

1.0

1.2

V

1.4

Max Duty Cycle “ON” (Note 4)

DC

95

%

Current Limit (Peak Current, Notes 3 and 4)

ICL

0.7

1.0

1.6

A

0.65

1.8

Output Leakage Current (Notes 5 and 6)

Output = 0 V

Output = −1.0 V

IL

mA

0.5

2.0

13

30

Quiescent Current (Note 5)

Standby Quiescent Current (ON/OFF Pin = 5.0 V (“OFF”))

(Note 6)

IQ

5.0

10

mA

Istby

50

200

mA

250

ON/OFF PIN LOGIC INPUT

Threshold Voltage

1.6

V

Vout = 0 V (Regulator OFF)

VIH

2.2

V

2.4

Vout = Nominal Output Voltage (Regulator ON)

VIL

1.0

V

0.8

ON/OFF Pin Input Current

ON/OFF Pin = 5.0 V (Regulator OFF)

IIH

−

15

30

mA

ON/OFF Pin = 0 V (regulator ON)

IIL

−

0.01

5.0

mA

1. External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance.

When the LM2594 is used as shown in the Figure 16 test circuit, system performance will be as shown in system parameters section.

2. The oscillator frequency reduces to approximately 30 kHz in the event of an output short or an overload which causes the regulated output

voltage to drop approximately 40% from the nominal output voltage. This self protection feature lowers the average dissipation of the IC by

lowering the minimum duty cycle from 5% down to approximately 2%.

3. No diode, inductor or capacitor connected to output (Pin 8) sourcing the current.

4. Feedback (Pin 4) removed from output and connected to 0 V.

5. Feedback (Pin 4) removed from output and connected to +12 V to force the output transistor “off”.

6. Vin = 40 V.

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