ADP5076ACBZ-R7 datasheet(20/23 Pages) AD

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ADP5076

Data Sheet

Rev. A | Page 20 of 23

ZCOMP2 is the impedance of the series RC network from the

COMP2 pin to the AGND pin.

GCS2 is the current sense transconductance gain (the inductor

current divided by the voltage at COMP2), which is internally

set by the ADP5076 and is 12.5 A/V.

ZOUT2 is the impedance of the load in parallel with the output

capacitor.

At crossover frequency (fC2), the ZCOMP2 is dominated by a

resistor (RC2), and the ZOUT2 is dominated by the impedance of the

output capacitor (COUT2). Therefore, when solving for the fC2, the

equation (by definition of the crossover frequency) is simplified to

(2 |

FB2

VL2

NEG

OUT2

| V













To solve for RC2, use the following equation:

2(2 |

OUT2

NEG

FB2

CS2

| (V















where GCS2 = 12.5 A/V.

Using typical values for VFB2 and GM2 results in

2094

| (

(2 |

OUT2

NEG











See the Specifications section for the typical values for VFB2 and

GM2. The typical value for VFB2 can be obtained by subtracting

(VREF − VFB2) from VREF.

For better accuracy, it is recommended to use the COUT2 value

expected under the dc bias conditions that the COUT2 value

operates under in the calculation for RC2.

After the compensation resistor is known, set the zero formed

by the CC2 and RC2 to one-fourth of the crossover frequency, or

π fR





where CC2 is the compensation capacitor.

ERROR

AMPLIFIER

REF2

gM2

FB2

COMP2

RC2

CC2

Figure 45. Compensation Component

COMMON APPLICATIONS

Table 10, Table 11, and Table 12 list a number of common

component selections for typical VIN and VOUT conditions.

These have been bench tested and provide an off the shelf solution.

When pairing a boost and inverting regulator bill of materials,

choose the same VIN and fSW.

ADP5076

SW1

COMP1

RC1

102kΩ

CC1

1nF

COMP2

RC2

61.9kΩ

CC2

2.2nF

EN1

SYNC

SLEW

SEQ

EN2

AGND

PVIN

AVIN

CIN

10µF

VIN

+5V

FB1

PD3S140

3.3µH

VIN

+5V

VIN

+5V

6.8µF

RFB1

137kΩ

RFT1

2.43MΩ

VPOS

+15V

SW2

PGND

FB2

VREF

PD3S140

RFB2

118kΩ

VNEG

–15V

CVREF

1µF

COUT1

10µF

COUT2

10µF

RFT2

2.32MΩ

Figure 46. Typical +5 V to ±15 V Application

Figure 46 shows the schematic referenced by Table 10, Table 11,

and Table 12 with example component values for +5 V to ±15 V

generation. Table 10 shows the components common to all of

the VIN and VOUT conditions.

Table 10. Recommended Common Components Selections

Reference

Value

Part Number

Manufacturer

Input

Capacitor

10 μF

GRM21BZ71C106KE15L

Murata

CVREF

1 μF

GRM188R71C105KA12C

Murata

Figure 47 shows the efficiency curves for the boost and inverting

regulator using the recommended small-sized components in

Table 10, Table 11, and Table 12 for VPOS = +15 V and VNEG =

−15 V at VIN = +5 V.

100

0.001

0.01

0.1

LOAD CURRENT (A)

VPOS = +15V, 2.4MHz

VPOS = +15V, 1.2MHz

VNEG = –15V, 1.2MHz

VNEG = –15V, 2.4MHz

Figure 47. Boost Regulator and Inverting Regulator Efficiency vs. Current

Load, TA = 25

°C

ADP5076ACBZ-R7 Datasheet(PDF) 20 Page - Analog Devices

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