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Evaluation Board User Guide

UG-334

One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com

Evaluation Board for the ADP1876 Step-Down DC-to-DC Controller

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT

WARNING AND LEGAL TERMS AND CONDITIONS.

Rev. 0 | Page 1 of 16

FEATURES

Input range: 10 V to 20 V

Two output voltages: 5 V and 1.8 V

Output current: 13 A per channel

Switching frequency: 600 kHz

Operates in PWM

Compact, low cost, and efficient design

EVALUATION BOARD DESCRIPTION

This user guide describes the design, operation, and test results

of the ADP1876-E VA L Z. The input range for this evaluation

board is 10 V to 20 V, and the two regulated output voltages are

set to 5 V (V

OUT1

) and 1.8 V (V

OUT2

) with a maximum 13 A output

current. The power components, such as the MOFSETS, inductors,

and bulk input and output capacitors, were chosen to yield a low

system cost and good efficiency.

ADP1876 DEVICE DESCRIPTION

The ADP1876 is a dual-channel, step-down switching controller

with integrated drivers for external N-channel synchronous power

MOSFETs. The two PWM outputs are phase shifted 180°, which

reduces the input rms ripple current, thus minimizing the required

input capacitance.

In addition, boost diodes are integrated into the ADP1876,

which lowers the overall system cost and component count. The

ADP1876 is configured to operate in forced PWM continuous

conduction mode.

The ADP1876 includes externally adjustable soft start, output

overvoltage protection, externally adjustable current limit,

power good and tracking function for Channel 1. The ADP1876

provides an output voltage accuracy of ±0.85% for a −40°C to

+85°C junction temperature and ±1.5% for a −40°C to +125°C

junction temperature. This controller can be powered from a

2.75 V to 20 V supply and is available in a 32-lead, 5 mm × 5 mm

lead frame chip scale package (LFCSP).

ADP1876-EVALZ EVALUATION BOARD

10272-001

ADP1876

GND

TERMINAL

VIN

TERMINAL

GND

TERMINAL

OUT1

TERMINAL

OUT2

TERMINAL

GND

TERMINAL

Figure 1.

Summary of content (16 pages)

PAGE 1
Evaluation Board User Guide UG-334 One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com Evaluation Board for the ADP1876 Step-Down DC-to-DC Controller FEATURES ADP1876 DEVICE DESCRIPTION Input range: 10 V to 20 V Two output voltages: 5 V and 1.
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UG-334 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Output Capacitors .........................................................................3 Evaluation Board Description......................................................... 1 MOSFET Selection ........................................................................3 ADP1876 Device Description ................................................
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Evaluation Board User Guide UG-334 COMPONENT DESIGN OUTPUT CAPACITORS For information about selecting power components and calculating component values, see the ADP1876 data sheet. A combination of POSCAP™ polymer capacitors and MLCCs are selected for the output rails. Polymer capacitors have low ESR and high current ripple rating. Connecting polymer capacitors and MLCCs in parallel is very effective in reducing voltage ripple.
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UG-334 Evaluation Board User Guide TEST RESULTS TA = 25°C. 100 T 90 VOUT1 = 5V 80 VOUT1 RIPPLE AT 10A SW1 VOUT2 = 1.8V 60 1 50 2 40 VOUT2 RIPPLE AT 10A SW2 30 TA = 25°C VIN = 12V 20 3 10 0 2 4 6 8 LOAD (A) 10 12 14 10272-002 4 0 BW BW CH1 20.0mV CH3 20.0mV Figure 2. Efficiency (Measurement Is Made with the Adjacent Channel Disabled) CH2 10.0V CH4 10.0V M1.00µs A CH4 10.2V 10272-005 EFFICIENCY (%) 70 Figure 5. Output Ripple, 10 A Load 0 T –0.005 VOUT2 = 1.
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Evaluation Board User Guide UG-334 0.035 T TA = 25°C VIN = 12V LINE REGULATION (%) 0.030 0.025 1 STEP LOAD 1mA TO 200mA CINLDO = 1µF, COUTLDO = 4.7µF 0.020 0.015 OUTPUT TRANSIENT 0.010 2 4.0 3.5 4.5 VINLDO (V) 5.0 5.5 6.0 CH1 100mA Ω BW CH2 50.0mV 0 TA = 25°C VIN = 12V –0.06 –0.08 –0.10 VINLDO = 5V –0.12 VINLDO = 3V –0.14 –0.16 –0.18 –0.20 0.025 0.050 0.075 0.100 0.125 VOUTLDO LOAD (A) 0.150 0.175 0.200 10272-009 LOAD REGULATION (%) –0.04 0 A CH1 Figure 10.
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UG-334 Evaluation Board User Guide EVALUATION BOARD OPERATING INSTRUCTIONS 1. 2. 3. Connect Jumper J3 (EN1) to the high position to enable Channel 1 of the ADP1876. Connect Jumper J2 (EN2) to the high position to enable Channel 2 of the ADP1876. Connect the positive terminal of the input power supply to the T1 input terminal. The input range is 10 V to 20 V, which powers up the ADP1876 IC. 4. Connect the positive terminal of another input power supply to the T7 input terminal (VINLDO).
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Evaluation Board User Guide UG-334 EVALUATION BOARD PCB LAYOUT As seen in Figure 1, the layout of this evaluation board is not optimized for the smallest PCB area. It is laid out in such a way that any of the components can be desoldered and replaced easily with different components with a hand soldering iron so that the user can modify the existing design without acquiring a new PCB layout.
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1 2 3 4 T14 TP-575-4 VDL TP16 VDL 1 T11 TURRET T2 1 T10 TURRET 1 2 3 4 T7 TP-575-4 T13 TP-575-4 VOUTLDO VINLDO VIN open RV5 100nf CVIN 1 1.0uF CV5 VCCO REN2 OPEN VEN1 TP3 1 T1 J2 2 Way Link 3 0 RVCC0 OPEN REN1 1 J3 VDL OPEN 0 3 VIN EN1 1 1.0uF EN1 750k RR2 44.2k FB1 29 73.2k RF11 RF21 20k RF22 10k 330pF 22pF NC AGND VDL VCCO VOUTLDO VINLDO VIN CC21 8 7 6 5 4 3 2 1 U1 120pF CC11 CC22 RC2 VOUTLDO 1uF 12.
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UG-334 10272-012 Evaluation Board User Guide 10272-013 Figure 12. Top Silkscreen Figure 13. Top Layer Rev.
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Evaluation Board User Guide 10272-014 UG-334 10272-015 Figure 14. Second Layer (AGND Plane) Figure 15. Third Layer (PGND Layer) Rev.
PAGE 11
UG-334 10272-016 Evaluation Board User Guide Figure 16. Bottom Layer (PGND Layer) Rev.
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UG-334 Evaluation Board User Guide ORDERING INFORMATION BILL OF MATERIALS Table 3. Qty 1 4 2 4 1 4 1 4 2 4 1 1 1 1 1 3 7 2 2 2 1 1 1 1 2 2 5 6 3 Reference Designator U1 QH1, QH3, QL2, QL3 L1, L2 COV1, COV2, COV5, COV6 CIN20 CIN11, CIN12, CIN21, CIN22 CVIN Css1, Css2, Cbst1, Cbst2 Cv5, Cdr COV13, COV23, COV12, COV22 CINLDO COUTLDO Cc11 Cc12 Cc21 Cc22, Clim1, Clim2 Rb0, Rvcco, RDH1, RDH2, RDL1, RDL2, Rt11 Description ADP1876, 32-lead LFCSP, 5 mm × 5 mm N MOSFET, 30 V, 6 mΩ Inductor, 1.8 µH, 3.
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Evaluation Board User Guide UG-334 NOTES Rev.
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UG-334 Evaluation Board User Guide NOTES Rev.
PAGE 15
Evaluation Board User Guide UG-334 NOTES Rev.
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UG-334 Evaluation Board User Guide NOTES ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.