Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - voltage regulators - DC DC switch controllers TSSOP 28 EP

General Description

The MAX5066 is a two-phase, configurable single- or

dual-output buck controller with an input voltage range of

4.75V to 5.5V or from 5V to 28V. Each phase of the

MAX5066 is designed for 180° operation. A mode pin

allows for a dual-output supply or connecting two phases

together for a single-output, high-current supply. Each

output channel of the MAX5066 drives n-channel

MOSFETs and is capable of providing more than 25A of

load current. The MAX5066 uses average current-mode

control with a switching frequency up to 1MHz per phase

where each phase is 180° out of phase with respect to

the other. Out-of-phase operation results in significantly

reduced input capacitor ripple current and output volt-

age ripple in dual-phase, single-output voltage applica-

tions. Each buck regulator output has its own high-

performance current and voltage-error amplifier that can

be compensated for optimum output filter L-C values and

transient response.

The MAX5066 offers two enable inputs with accurate

turn-on thresholds to allow for output voltage sequencing

of the two outputs. The device’s switching frequency can

be programmed from 100kHz to 1MHz with an external

resistor. The MAX5066 can be synchronized to an exter-

nal clock. Each output voltage is adjustable from 0.61V to

5.5V. Additional features include thermal shutdown, “hic-

cup mode” short-circuit protection. Use the MAX5066

with adaptive voltage positioning for applications that

require a fast transient response, or accurate output volt-

age regulation.

The MAX5066 is available in a thermally enhanced 28-pin

TSSOP package capable of dissipating 1.9W. The device

is rated for operation over the -40°C to +85°C extended,

or -40°C to +125°C automotive temperature range.

Applications

High-End Desktop Computers

Graphics Cards

Networking Systems

Point-of-Load High-Current/High-Density

Telecom DC-DC Regulators

RAID Systems

Features

♦ 4.75V to 5.5V or 5V to 28V Input

♦ Dual-Output Synchronous Buck Controller

♦ Configurable for Two Separate Outputs or One

Single Output

♦ Each Output is Capable of Up to 25A Output

Current

♦ Average Current-Mode Control Provides Accurate

Current Limit

♦ 180° Interleaved Operation Reduces Size of Input

Filter Capacitors

♦ Limits Reverse Current Sinking When Operated in

Parallel Mode

♦ Each Output is Adjustable from 0.61V to 5.5V

♦ Independently Programmable Adaptive Voltage

Positioning

♦ Independent Shutdown for Each Output

♦ 100kHz to 1MHz per Phase Programmable

Switching Frequency

♦ Oscillator Frequency Synchronization from

200kHz to 2MHz

♦ Hiccup Mode Overcurrent Protection

♦ Overtemperature Shutdown

♦ Thermally Enhanced 28-Pin TSSOP Package

Capable of Dissipating 1.9W

♦ Operates Over -40°C to +85°C or -40°C to +125°C

Temperature Range

MAX5066

Configurable, Single-/Dual-Output, Synchronous

Buck Controller for High-Current Applications

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3661; Rev 1; 8/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE PIN-PACKAGE

MAX5066EUI -40°C to +85°C 28 TSSOP-EP*

MAX5066AUI -40°C to +125°C 28 TSSOP-EP*

*Exposed Pad

Summary of content (22 pages)

PAGE 1
9-3661; Rev 1; 8/05 KIT ATION EVALU LE B A IL A AV Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications The MAX5066 is a two-phase, configurable single- or dual-output buck controller with an input voltage range of 4.75V to 5.5V or from 5V to 28V. Each phase of the MAX5066 is designed for 180° operation. A mode pin allows for a dual-output supply or connecting two phases together for a single-output, high-current supply.
PAGE 2
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications ABSOLUTE MAXIMUM RATINGS IN to AGND.............................................................-0.3V to +30V BST_ to AGND........................................................-0.3V to +35V DH_ to LX_ ....................................-0.3V to (VBST_ - VLX_) + 0.3V DL_ to PGND ..............................................-0.3V to (VDD + 0.3V) BST_ to LX_ ................................................
PAGE 3
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications (VIN = VREG = VDD = VEN_ = +5V, TA = TJ = TMIN to TMAX, unless otherwise noted, circuit of Figure 6. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS OSCILLATOR Switching Frequency fSW Switching Frequency Accuracy 1MHz (max) switching frequency per phase RRT = 12.4kΩ 1000 RRT = 127kΩ 100 kHz fSW = 250kHz nominal, RRT = 50kΩ -7.5 +7.
PAGE 4
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications ELECTRICAL CHARACTERISTICS (continued) (VIN = VREG = VDD = VEN_ = +5V, TA = TJ = TMIN to TMAX, unless otherwise noted, circuit of Figure 6. Typical values are at TA = +25°C.
PAGE 5
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications 16 SUPPLY CURRENT (mA) 1000 100 10 fSW = 500kHz 12 10 8 fSW = 250kHz 6 16 fSW = 125kHz 12 fSW = 1MHz fSW = 500kHz 10 8 fSW = 250kHz 6 4 2 2 0 fSW = 125kHz 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 RT (kΩ) TEMPERATURE (°C) TEMPERATURE (°C) SUPPLY CURRENT vs. TEMPERATURE AND FREQUENCY (VIN = 24V) SUPPLY CURRENT vs. OSCILLATOR FREQUENCY SUPPLY CURRENT vs.
PAGE 6
Typical Operating Characteristics (continued) (Circuit of Figure 6, TA = +25°C, unless otherwise noted. VIN = 12V, VOUT1 = 0.8V, VOUT2 = 1.3V, fSW = 500kHz per phase.) 90 80 70 3.300 60 tRISE (ns) 3.301 3.299 30 DL 50 5 10 3.296 0 5 7 9 11 13 15 17 19 21 DL 20 10 20 IREF = 200µA 25 15 30 3.297 DH DH 40 3.298 35 tFALL (ns) IREF = 0 40 MAX5066 toc09 3.302 100 MAX5066 toc08 3.303 DRIVER FALL TIME vs.
PAGE 7
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications LOW-SIDE DRIVER FALL TIME (VIN = 12V, CLOAD = 10nF) OUT1/OUT2 OUT-OF-PHASE WAVEFORMS (VOUT1 = 0.8V, VOUT2 = 1.
PAGE 8
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications MAX5066 Pin Description PIN NAME 1 CSN2 Current-Sense Differential Amplifier Negative Input for Output2. Connect CSN2 to the negative terminal of the sense resistor. The differential voltage between CSP2 and CSN2 is internally amplified by the current-sense amplifier (AV(CS) = 36V/V). 2 CSP2 Current-Sense Differential Amplifier Positive Input for Output2.
PAGE 9
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications PIN NAME FUNCTION 14 CSN1 15 EN1 Output 1 Enable. A logic-low shuts down channel 1’s MOSFET drivers. EN1 can be used for output sequencing. 16 BST1 Boost Flying Capacitor Connection. Reservoir capacitor connection for the high-side MOSFET driver supply. Connect a 0.47µF ceramic capacitor between BST1 and LX1. 17 DH1 High-Side Gate Driver Output1. DH1 drives the gate of the high-side MOSFET.
PAGE 10
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications 13 CSP1 CLP1 10 EAOUT1 12 EAN1 11 CA1 14 CSN1 DF1 AND HICCUP LOGIC CEA1 VEA1 16 BST1 CPWM1 17 DH1 IN 22 REG 21 EN1 15 REF 6 UVLO VREG = 5V 2VP-P RAMP CONTROL AND DRIVER LOGIC 1 FOR INTERNAL BIASING 18 LX1 20 VDD 19 DL1 CEN1 0° 1.225V VREF = 3.3V VINTREF = 0.61V THERMAL SHUTDOWN UV33 OSCILLATOR AND PHASE SPLITTER 1.
PAGE 11
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications Dual-Output/Dual-Phase Select (MODE) The MAX5066 can operate as a dual-output independently regulated buck converter, or as a dual-phase, single-output buck converter. The MODE input selects between the two operating modes. When MODE is grounded (logic low), VEA1 and VEA2 connect to CEA1 and CEA2, respectively (see Figure 1) and the device operates as a two-output DC-DC converter.
PAGE 12
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications Hiccup Fault Protection The MAX5066 includes overload fault protection circuitry that prevents damage to the power MOSFETs. The fault protection consists of two digital fault integration blocks that enable “hiccuping” under overcurrent conditions. This circuit works as follows: for every clock cycle the current-limit threshold is exceeded, the fault integration counter increments by one count.
PAGE 13
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications Peak-Current Comparator The peak-current comparator (see Figure 3) monitors the voltage across the current-sense resistor (RSENSE) and provides a fast cycle-by-cycle current limit with a threshold of 52.5mV. Note that the average current-limit threshold of 22.5mV still limits the output current during short-circuit conditions.
PAGE 14
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications VDD PEAK-CURRENT COMPARATOR 52.5mV CLP_ AV = 36 CSP_ gM = 500µS CSN_ BST_ PWM COMPARATOR GMIN Q S DH_ RAMP LX_ 2 x fSW (V/S) CLK R Q DL_ 1.225V PGND EN_ Figure 3. Current Comparator and MOSFET Driver Logic VOUT VOLTAGE-POSITIONING WINDOW VCNTR + ∆VOUT/2 RF VCNTR R1 COUT EAN_ LOAD VCNTR - ∆VOUT/2 EAOUT_ R2 VREF = 0.61V NO LOAD 1/2 LOAD FULL LOAD LOAD (A) Figure 4.
PAGE 15
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications MAX5066 VIN IN VDD D1 (100mA, 30V) REG BST1 0.8V/10A C8 0.1µF BST2 C4 4.7µF C9 0.1µF DH2 LX1 Q1 IRF7832 LX2 DL1 D3 (1A, 30V) C3 0.1µF Q4 IRF7821 DH1 MAX5066 C6 680µF D2 (100mA, 30V) 22Ω Q2 IRF7821 L1 0.5µH R3 1Ω 22Ω C2 1µF R1 2mΩ C5 10µF L2 0.8µH Q3 IRF7832 D4 (1A, 30V) DL2 R2 2mΩ 1.3V/10A C7 680µF PGND R4 1.74kΩ CSP1 CSN1 CSP2 EAN1 CSN2 EAN2 EAOUT1 R5 4.64kΩ EAOUT2 R8 29.
PAGE 16
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications VIN IN VDD D1 (100mA, 30V) 1.3V/20A REG BST1 L1 0.8µH C8 0.1µF C3 0.1µF BST2 Q4 IRF7821 DH1 C9 0.1µF DH2 LX1 Q1 IRF7832 L2 0.8µH LX2 Q3 IRF7832 DL1 D3 (1A, 30V) D2 (100mA, 30V) 22Ω Q2 IRF7821 MAX5066 C6 680µF R3 1Ω 22Ω C2 1µF R1 2mΩ C5 10µF D4 (1A, 30V) DL2 PGND R4 5.11kΩ CSP1 CSN1 CSP2 EAN1 CSN2 EAN2 EAOUT1 R5 4.75kΩ EAOUT2 R8 60.
PAGE 17
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications inductor with a saturating current greater than the worst-case peak inductor current: Design Procedures Inductor Selection The switching frequency per phase, peak-to-peak ripple current in each phase, and allowable voltage ripple at the output, determine the inductance value.
PAGE 18
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications Table 1. High-Side MOSFET Losses LOSS DESCRIPTION Conduction Loss Losses associated with MOSFET on-time and on-resistance. IRMS is a function of load current and duty cycle. Gate Drive Loss Losses associated with charging and discharging the gate capacitance of the MOSFET every cycle. Use the MOSFET’s (QG) specification.
PAGE 19
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications MAX5066 Table 2. Low-Side MOSFET Losses LOSS DESCRIPTION SEGMENT LOSSES PCONDUCTION = IRMS 2 × RDS(ON) Conduction Loss Losses associated with MOSFET on-time, IRMS is a function of load current and duty cycle. Gate Drive Loss Losses associated with charging and discharging the gate of the MOSFET every cycle. There is no QGD charging involved in this MOSFET due to the zero-voltage turn-on.
PAGE 20
MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications 1.63 × 10 −3 IREVERSE = RSENSE Output-Voltage Setting The output voltage is set by the combination of resistors R1, R2, and RF as described in the Voltage Error Amplifier section. First select a value for resistor R2. Then calculate the value of R1 from the following equation: R1 = (VOUT(NL) − 0.6135) 0.6135 × R2 where VOUT(NL) is the voltage at no load.
PAGE 21
Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications CCFF = 1 2 × π × fC × 10 × RCF where CCFF is C11 and C13 in Figure 6. Applications Information 8) Distribute the power components evenly across the top side for proper heat dissipation. 9) Keep AGND and PGND isolated and connect them at one single point close to the IC. Do not connect them together anywhere else. 10) Place all input bypass capacitors for each input as close to each other as is practical.
PAGE 22
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) TSSOP 4.4mm BODY.EPS MAX5066 Configurable, Single-/Dual-Output, Synchronous Buck Controller for High-Current Applications XX XX PACKAGE OUTLINE, TSSOP, 4.40 MM BODY, EXPOSED PAD 21-0108 E 1 1 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product.