MAX8515E_K データシートの表示（PDF） - Maxim Integrated

部品番号

コンポーネント説明

メーカー

MAX8515E_K

Wide-Input 0.6V Shunt Regulators for Isolated DC-to-DC Converters

Maxim Integrated 

Wide-Input 0.6V Shunt Regulators for

Isolated DC-to-DC Converters

VIN

1.8V

R3

C1

0.1µF

IN

OUT

MAX8515A

MAX8515

PGND

GND

FB

VOUT

0.6V/20mA

R1 = SHORT

R2 = OPEN

C2

1.0µF

R1

VIN (V) R3 (Ω)

3.3 135

10 470

R2

28 1.33k

Figure 1. MAX8515A/MAX8515 Typical Application Circuit,

Shunt Regulator/Adjustable Voltage Reference

Optical Feedback

Setting VOUT

Figure 3 displays an application circuit using the

MAX8515A/MAX8515 in an opto-isolated feedback cir-

cuit. The maximum bias current for the photodiode is

set with R1. The isolated DC-to-DC converter compen-

sation circuit is formed with R2, C3, and C4. Resistors

R3 and R4 set the isolated DC-to-DC converter output

voltage. C1 decouples the input supply and C2 is

needed to stabilize the MAX8515A/MAX8515. Calculate

VREG with the following equation:

VREG = 0.6 ×

1 +

R3 

R4 

Set R4 to 10kΩ and calculate R3 by:

R3

=





VOUT

VFB



- 1

×

R4

For example, given a regulator output voltage of 1.8V

and R4 = 10kΩ, R3 is found to be 20kΩ.

Compensation Circuit

A typical compensation scheme is depicted in Figure 3.

C3 provides an integrator function that minimizes out-

put regulation error.

R2 provides additional phase compensation at the zero

frequency fz:

fZ

=

2π

×

1

R2

×

C3

5.6V

3.3V

VOUT = 0.6V

TEST CIRCUIT

0.1µF

IN

OUT

MAX8515A

MAX8515

PGND

GND

FB

GAIN = TEST/REFERENCE

1kΩ

TEST

2.2nF

1MΩ

0.82µF

50kΩ

2.2nF

REFERENCE

1MΩ

NETWORK

ANALYZER

SOURCE

11V

3.3V

VOUT = 6V

TEST CIRCUIT

115kΩ

1%

TEST

2.2nF

1MΩ

160kΩ

0.1µF

IN

OUT

MAX8515A

MAX8515

PGND

GND

FB

10kΩ

1%

GAIN = TEST/REFERENCE

0.1µF

50kΩ

90.1kΩ

1%

2.2nF

NETWORK

ANALYZER

SOURCE

REFERENCE

1MΩ

Figure 2. Test Circuits for Gain and Phase Plots

The midband gain is given by:

A = R2

R3

Add C4 for high-frequency noise rejection. Determine

R2 based on the midband gain required by the isolated

power supply. Choose fz based on the power supply

small-signal transfer function. Calculate C3 once fz

is known.

_______________________________________________________________________________________ 5

Share Link: