ADP1876-EVALZ AD [Analog Devices], ADP1876-EVALZ Datasheet

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ADP1876-EVALZ

Manufacturer Part Number
ADP1876-EVALZ
Description
600 kHz Dual Output Synchronous Buck
Manufacturer
AD [Analog Devices]
Datasheets
Data Sheet
FEATURES
Wide input range: 2.75 V to 20 V
Power stage input voltage: 1 V to 20 V
Output voltage range: 0.6 V up to 90% V
Linear dropout (LDO) regulator with a fixed output
Output current more than 25 A per channel
180º phase shift between channels for reduced input
±0.85% reference voltage accuracy from −40°C to +85°C
Integrated boost diodes
Independent channel precision enable
Overcurrent limit protection
Externally programmable soft start, slope compensation,
Thermal overload protection
Input undervoltage lockout (UVLO)
Power good with internal pull-up resistor
Available in 32-lead, 5 mm × 5 mm LFCSP
APPLICATIONS
Consumer applications
Telecommunications base station and networking
Industrial and instrumentation
GENERAL DESCRIPTION
The
controller operating at 600 kHz fixed frequency with integrated
drivers that drive N-channel power MOSFETs. An additional
fixed voltage output, 150 mA linear regulator is available for
powering low power loads. The device operates in current
mode for improved transient response and uses valley current
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
1.5 V at 150 mA
capacitance
and current sense gain
ADP1876
is a dual output dc-to-dc synchronous buck
IN
600 kHz Dual Output Synchronous Buck
PWM Controller with Linear Regulator
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
3V to 5V INPUT
sensing for enhanced noise immunity. The two PWM outputs
are phase shifted 180° for reducing the input current ripple and
the required input capacitance.
The
capability with dead time optimization to enable energy
efficient power conversion.
ADP1876
1.5V
TYPICAL OPERATION CIRCUIT
provides high speed, high peak current drive
EN1
EN2
VDL
VCCO
TRK1
PGOOD1
PGOOD2
VINLDO
VOUTLDO
NC
COMP1
COMP2
SS1
SS2
AGND
RAMP1
ADP1876
R
RAMP1
©2011 Analog Devices, Inc. All rights reserved.
RAMP2
PGND1
PGND2
VIN
BST1
ILIM1
BST2
ILIM2
SW1
SW2
Figure 1.
DH1
DH2
FB1
DL1
FB2
DL2
R
RAMP2
R
R
CSG1
CSG2
V
IN
M1
M2
M3
M4
ADP1876
L1
L2
R11
R12
R21
R22
V
www.analog.com
IN
V
V
OUT1
OUT2

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ADP1876-EVALZ Summary of contents

Page 1

... One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 Fax: 781.461.3113 ADP1876 TYPICAL OPERATION CIRCUIT RAMP1 RAMP1 VIN ADP1876 M1 EN1 L1 DH1 EN2 BST1 VDL SW1 R11 ILIM1 VCCO FB1 TRK1 ...

Page 2

... ADP1876 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 Typical Operation Circuit ................................................................ 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Functional Block Diagram .............................................................. 3 Specifications ..................................................................................... 4 Absolute Maximum Ratings ....................................................... 7 ESD Caution .................................................................................. 7 Pin Configuration and Function Descriptions ............................. 8 Typical Performance Characteristics ........................................... 10 Theory of Operation ...................................................................... 14 Independent Low Dropout Linear Regulator ......................... 14 Controller Architecture ............................................................. 14 Input Undervoltage Lockout ..................................................... 14 Internal Linear Regulator (VCCO) ...

Page 3

... Figure 2. Functional Block Diagram Rev Page 0.6V UV ADP1876 VCCO OV1 LOGIC UV1 12kΩ + – + – VCCO DRIVER LOGIC CONTROL AND STATE MACHINE DCM + – CS GAIN VCCO – CURRENT SENSE AMPLIFIER + 50µA + – ADP1876 AGND PGOOD1 BST1 DH1 SW1 VDL DL1 PGND1 ILIM2 ...

Page 4

... ADP1876 SPECIFICATIONS All limits at temperature extremes are guaranteed via correlation using standard statistical quality control. V are valid for T = −40°C to +125°C, unless otherwise specified. Typical values are Table 1. Parameter POWER SUPPLY Input Voltage Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis ...

Page 5

... ADP1876 Unit Ω Ω %/°C Ω Ω °C ° μA kΩ kΩ μs μs mV μA ns Ω μ ...

Page 6

... ADP1876 Parameter RMS Output Noise Short-Circuit Current Undervoltage Lockout Threshold Undervoltage Lockout Hysteresis 1 Guaranteed by design. Not production tested. 2 Connect V to VCCO when V < 5 Symbol Test Conditions/Comments 100 kHz, VINLDO = GND OUTLDO V V rising INLDO_UVLO INLDO V INLDO Rev Page ...

Page 7

... Unless otherwise specified, all other voltages are 32 V referenced to GND ESD CAUTION −8 V −0 +0.3 V − 32.6°C/W −40°C to +125°C −65°C to +150°C 260°C , and the junction Maximum junction . Rev Page ADP1876 ...

Page 8

... Boot Strapped Upper Rail of High-Side Internal Driver for Channel 2. Connect a 0.1 µF to 0.22 µF multilayer ceramic capacitor (MLCC) between BST2 and SW2. There is an internal boost rectifier connected between VDL and BST2. EN1 1 24 SW1 2 23 DH1 VIN VINLDO 3 22 PGND1 ADP1876 VOUTLDO 21 DL1 4 TOP VIEW 5 20 DL2 VCCO (Not to Scale) VDL 6 ...

Page 9

... RAMP1 is 0.2 V during operation. This pin is high impedance when the channel is disabled. 30 COMP1 Compensation Node For Channel 1. Output of Channel 1 error amplifier. Connect a series resistor/capacitor network from COMP1 to AGND to compensate the regulation control loop. 31 FB1 Output Voltage Feedback for Channel 1. 32 TRK1 Tracking Input for Channel 1. Rev Page ADP1876 ...

Page 10

... ADP1876 TYPICAL PERFORMANCE CHARACTERISTICS Test conditions are 25°C and 100 1. OUT OUT 12V LOAD (A) Figure 4. Efficiency Plot of Figure 33 0 –0.05 –0.10 50mA LOAD –0.15 100mA LOAD –0.20 –0.25 2.5 3.0 3.5 4.0 V (V) IN Figure 5. VCCO Dropout 5 ...

Page 11

... DHx MINIMUM ON TIME 100 50 2.5 5.0 7.5 10.0 12.5 15.0 V (V) IN Figure 14. Typical DHx Minimum On Time and Off Time 4 3 DHx MINIMUM OFF TIME 2 1 DHx MINIMUM ON TIME 0 –1 –2 –3 –4 –40 – TEMPERATURE (°C) ADP1876 110 135 17.5 20.0 110 135 ...

Page 12

... ADP1876 12V IN OUTPUT IS LOADED 34 HS FET = BSC080N03LS LS FET = BSC030N03LS DEAD TIME BETWEEN SWx FALLING EDGE AND DLx RISING EDGE, INCLUDING DIODE RECOVERY TIME 25 –40 – TEMPERATURE (°C) Figure 16. Dead Time vs. Temperature OUTPUT IS LOADED ...

Page 13

... VOUTLDO LOAD (A) Figure 22. VOUTLDO Noise Spectral Density 1 2 CH1 100m 1 Rev Page ADP1876 STEP LOAD 1mA TO 200mA CINLDO = 1µF; COUTLDO = 4.7µF OUTPUT TRANSIENT 100mA Ω CH2 50.0mV M10.0µs A CH1 W W Figure 23. VOUTLDO Step Load Transient ...

Page 14

... Synchronous Rectifier and Dead Time The synchronous rectifier (low-side MOSFET) improves efficiency by replacing the Schottky diode that is normally used in an asynchronous buck regulator. In the ADP1876, the antishoot through circuit monitors the SW and DL nodes and adjusts the low-side and high-side drivers to ensure break-before-make switching to prevent cross conduction or shoot through between the high-side and low-side MOSFETs ...

Page 15

... V IN The EN1 and EN2 pins enable or disable Channel 1 and Channel 2, respectively, of the ADP1876. The precision enable threshold for EN1 or EN2 is typically 0.63 V. When the EN1 or EN2 voltage rises above 0.63 V, the and starts normal operation after the soft start period. When the voltage at ENx drops below 0 ...

Page 16

... VCCO, and VOUTLDO are turned off and SSx discharges toward zero through an internal 1 kΩ resistor. When the junction temperature drops below 135°C, the resumes normal operation after the soft start sequence. Rev Page Data Sheet ADP1876 ...

Page 17

... When the drop ILIM is equal to or greater than DSON ADP1876 flags a current-limit event. DSON of the MOSFET at its highest DSON × LPK DSON _ MAX = 40 μA by replacing R ILIM . See Figure 28 for the implementation of this ADP1876 vary over is DSON DSON_MAX ...

Page 18

... R value that produces between 6 µA and 20 µA. RAMP Figure 29 illustrates the connection of the slope compensation resistor and the current sense gain resistor, R RAMP R RAMP RAMP ADP1876 DHx SWx R ILIM ILIMx DLx R PGNDx CSG Figure 29. Slope Compensation and CS Gain Connection ...

Page 19

... L is the equivalent series inductance of the output capacitor ESL (or the parallel combination of ESL of all capacitors). Solving C in the previous equation yields OUT ∆ I ≅ OUT Rev Page ADP1876 ADP1876 V × OUT   1   ×  ...

Page 20

... V   2 ≅ × OUT (   C LOAD DSON V   IN ≅ V × Q × ADP1876 internal drivers. This × × + × LOAD SW ≅ can be estimated by the following equations ≅ GSW R I DRIVER ...

Page 21

... V is the forward voltage drop of the body diode, typically 0 the dead time in the ADP1876, typically 30 ns when driving D some medium-size MOSFETs with input capacitance, C approximately 3 nF. The dead time is not fixed. Its effective value varies with gate drive resistance and high load current designs and low voltage designs ...

Page 22

... ADP1876 Because the zero produced by the ESR of the output capacitor is not needed to stabilize the control loop, assuming ESR is small, the ESR is ignored for analysis. Then FILTER sC OUT Because C is small relative COMP COMP + COMP COMP sC COMP ...

Page 23

... Figure 33. Typical Applications Circuit Rev Page Note, Printed Circuit Board Layout Guidelines for V = 10V TO 14V IN M1 CIN CIN1 L1 2.1kΩ COUT COUT 11 M2 22kΩ CIN2 L2 2.1kΩ COUT COUT M4 21 22kΩ PGND ADP1876 AN-1119 V OUT1 5V@ 13A 12 V OUT2 1.8V@ 13A 22 ...

Page 24

... OUTLINE DIMENSIONS PIN 1 INDICATOR 0.80 0.75 0.70 SEATING PLANE ORDERING GUIDE 1 Model Temperature Range ADP1876ACPZ-R7 −40°C to +85°C ADP1876-EVALZ RoHS Compliant Part. ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10103-0-11/11(A) 5.10 0.30 5.00 SQ 0.25 4.90 0.18 25 0.50 BSC 16 0 ...

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