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Evaluation Board User Guide

UG-205

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

Evaluation Board for the ADP1850DP Step-Down DC-to-DC Controller

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT

WARNING AND LEGAL TERMS AND CONDITIONS.

Rev. A | Page 1 of 12

FEATURES

Input range: 10 V to 15 V

Output voltage: 1.09 V

Output current: 50 A

Switching frequency: 300 kHz

Operates in PWM

Compact, low cost, and efficient design

EVALUATION BOARD DESCRIPTION

This document describes the design, operation, and test results

of the ADP1850DP-EVALZ operating in dual-phase mode. The

input range for this evaluation board is 10 V to 15 V, and the

regulated output voltage is 1.09 V with a maximum 50 A output

current. A switching frequency (f

) of 300 kHz is chosen to

achieve a good balance between efficiency and the sizes of the

power components.

ADP1850 DEVICE DESCRIPTION

The ADP1850 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

required input capacitance. The two outputs can be combined

for dual-phase PWM operation that can deliver more than 50 A

output current. The internal parameters of the two channels are

optimized for current sharing.

In addition, boost diodes are integrated into the ADP1850,

thus lowering the overall system cost and component count.

The ADP1850 can be set to operate in pulse skip, high

efficiency mode under light load or in PWM continuous

conduction mode.

The ADP1850 includes externally adjustable soft start, output

overvoltage protection, externally adjustable current limit,

power good, tracking function, and a programmable oscillator

frequency that ranges from 200 kHz to 1.5 MHz. The ADP1850

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

+85°C and ±1.5% from −40°C to +125°C junction temperature.

This controller may be powered from a 2.75 V to 20 V supply is

available in a 32-lead 5 mm × 5 mm LFCSP package.

ADP1850DP EVALUATION BOARD

09456-001

VIN TERMINALGND TERMINAL

DP1850

GND TERMINAL

VOUT TERMINAL

Figure 1.

Summary of content (12 pages)

PAGE 1
Evaluation Board User Guide UG-205 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 ADP1850DP Step-Down DC-to-DC Controller power MOSFETs. The two PWM outputs are phase shifted 180°, which reduces the input RMS ripple current, thus minimizing required input capacitance. The two outputs can be combined for dual-phase PWM operation that can deliver more than 50 A output current.
PAGE 2
UG-205 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Output Capacitors .........................................................................3 Evaluation Board Description......................................................... 1 MOSFET Selection........................................................................3 ADP1850 Device Description..................................................
PAGE 3
Evaluation Board User Guide UG-205 COMPONENT DESIGN For information about selecting power components and calculating component values, see the ADP1850 data sheet. OUTPUT CAPACITORS INDUCTOR SELECTION A 0.47 μH inductor with a 50 A saturation current rating and a 30 A average current rating (744355147 from Würth Elektronik) is selected. This is a compact inductor with an iron alloy core, which offers high performance in terms of low RDC and low core loss.
PAGE 4
UG-205 Evaluation Board User Guide TEST RESULTS TA = 25°C. 100 90 SW1 80 1 SW2 60 3 50 40 4 30 20 VIN = 12V VOUT = 1.09V fSW = 300kHz 0 0 10 20 30 40 OUTPUT RIPPLE 50 LOAD (A) 09456-002 10 CH1 10V CH3 10V Figure 2. Efficiency CH4 20mV M2µs A CH3 10.2V 09456-005 EFFICIENCY (%) 70 Figure 5. Output Ripple, 50 A Load 0.10 fSW = 300kHz, 25A LOAD 0.08 LINE REGULATION (%) 0.06 0.04 1A TO 16A STEP LOAD 0.02 3 0 –0.02 OUTPUT RESPONSE VOUT = 1.09V 4 –0.04 –0.
PAGE 5
Evaluation Board User Guide UG-205 EVALUATION BOARD OPERATING INSTRUCTION 1. 2. Connect Jumper J3 (EN) to the high position to enable Channel 1 and Channel 2 of the ADP1850. Jumper J3 is connected to both EN1 and EN2. Connect Jumper J4 (FREQ) to the low position for 300 kHz operation. 3. 4. Connect Jumper J1 (SYNC) to the high position for PWM operation. Connect the positive terminal of the input power supply to the input terminal, T1. The input range is 10 V to 15 V. Table 1.
PAGE 6
UG-205 Evaluation Board User Guide OTHER INFORMATION ABOUT THE 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.
PAGE 7
1 1 VDL 1 2 3 4 1 VDL TP16 TURRET T11 T2 TURRET 2 RB0 open RFREQ 100nf CVIN 1 J1 VCC 2 T10 VIN 1 TP3 J4 SYNC 3 2 Way Link VCC 1 J3 VCC RT22 RT21 0 1.0uF TP5 CDR VDL VCC 1.0uF TRK2 EN1 0 R103 CV5 2 1 REN11 RVCC0 REN12 VIN 3 2 Way Link FREQ open RV5 SYNC 2 Way Link 3 1 2 1 2 3 4 2 T1 VIN 137k RR2 EN2 8 7 6 5 4 3 2 1 8.
PAGE 8
Evaluation Board User Guide 09456-008 UG-205 09456-009 Figure 8. Top Silkscreen Figure 9. Top Layer Rev.
PAGE 9
UG-205 09456-010 Evaluation Board User Guide 09456-011 Figure 10. Second Layer (AGND Plane) Figure 11. Third Layer (PGND Layer) Rev.
PAGE 10
Evaluation Board User Guide 09456-012 UG-205 09456-013 Figure 12. Bottom Layer (PGND Layer) Figure 13. Bottom Silk Screen Rev.
PAGE 11
Evaluation Board User Guide UG-205 ORDERING INFORMATION BILL OF MATERIALS Table 3.
PAGE 12
UG-205 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.