Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - power supply controllers/monitors 6 mA TQFN 32 EP (5x5)

Triple-Output Buck Controllers

with Tracking/Sequencing

MAX15048/MAX15049

EVALUATION KIT AVAILABLE

General Description

The MAX15048/MAX15049 are triple-output pulse-width

modulated (PWM), step-down, DC-DC controllers with

tracking (MAX15048) and sequencing (MAX15049)

options. The devices operate over the 4.7V to 23V input-

voltage range. Each PWM controller provides an adjustable

output down to 0.6V and delivers up to 15A of load current

with excellent load and line regulation. The MAX15049 can

start into prebiased outputs. The MAX15048/MAX15049

are optimized for high-performance, small-size power-

management solutions.

The options of coincident or ratiometric tracking (MAX15048)

or output sequencing (MAX15049) allow the tailoring of

the power-up/power-down sequence depending on the

system requirements. Each of the MAX15048/MAX15049

PWM sections utilizes a voltage-mode control scheme with

external compensation, allowing for good noise immunity

and maximum flexibility with a wide selection of inductor

values and capacitor types. Each PWM section operates at

the same fixed switching frequency that is programmable

from 200kHz to 1.2MHz. Each converter, operating at up to

1.2MHz with 120N out-of-phase, increases the input capaci-

tor ripple frequency up to 3.6MHz, reducing the RMS input

ripple current and thus the size of the input bypass capaci-

tor significantly. The MAX15048/MAX15049 integrate boost

diodes for additional system cost savings.

The MAX15048/MAX15049 include internal undervolt-

age lockout (UVLO) with hysteresis and digital soft-start

(MAX15048/MAX15049)/soft-stop (MAX15048) for glitch-

free power-up and power-down of the converter. The

power-good circuitry (PGOOD) monitors all three outputs

and provides a power-good signal to the system control/

processor when all outputs are within regulation. Protection

features include lossless valley-mode current limit, hiccup

mode output short-circuit protection, and thermal shutdown.

The MAX15048/MAX15049 are available in space-saving,

5mm x 5mm, lead-free, 32-pin TQFN-EP packages and

are specified for operation over the -40NC to +85NC

extended temperature range.

Applications

Point-of-Load DC-DC Converters

ASIC/CPU/DSP Core and I/O Voltages

DDR Power Supply

Base-Station Power Supplies

Telecom and Networking Power Supplies

RAID Control Power Supplies

Set-Top Boxes

Features

S 4.7V to 23V or 5V ±10% Input Voltage Range

Triple-Output Synchronous Buck Controllers with

120° Out-of-Phase Operation

Prebias Power-Up (MAX15049)

Output Voltage Adjustable Down to 0.6V

Coincident/Ratiometric Tracking (MAX15048)

Accurate Sequencing Through Enable Threshold

(MAX15049)

External Compensation for Maximum Flexibility

Digital Soft-Start (MAX15048/MAX15049) and Soft-

Stop (MAX15048)

Lossless Valley-Mode Current Sensing Using

DS(ON)

of the Low-Side MOSFET

PGOOD Output

Integrated Bootstrap Diodes

Programmable Switching Frequency from 200kHz

to 1.2MHz

Thermal Shutdown and Hiccup Mode Short-Circuit

Protection

Space-Saving (5mm x 5mm), 32-Pin TQFN

Package

19-5110; Rev 0; 1/10

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

Ordering Information

Simplified Typical Operating

Circuit (Coincident Tracking)

PART TEMP RANGE PIN-PACKAGE

MAX15048ETJ+ -40

C to +85

C 32 TQFN-EP*

MAX15049ETJ+ -40

C to +85

C 32 TQFN-EP*

LX1

BST1

PGND1

FB1

COMP1

OUT1

DH1

DL1

EN1

OUT3

OUT2

LX2

BST2

PGND2

FB2

COMP2

DH2

DL2

EN2

LX3

BST3

PGND3

FB3

COMP3

DH3

DL3

EN3

REG

SGND

PGOOD

REG

OUT1

OUT2

OUT3

SOFT-START SOFT-STOP

COINCIDENT TRACKING OUTPUTS

MAX15048

For pricing, delivery, and ordering information, please contact Maxim Direct

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

Summary of content (31 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing General Description Features The MAX15048/MAX15049 are triple-output pulse-width modulated (PWM), step-down, DC-DC controllers with tracking (MAX15048) and sequencing (MAX15049) options. The devices operate over the 4.7V to 23V inputvoltage range. Each PWM controller provides an adjustable output down to 0.6V and delivers up to 15A of load current with excellent load and line regulation.
PAGE 2
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing ABSOLUTE MAXIMUM RATINGS IN, LX_ to SGND....................................................-0.3V to +30V BST_ to SGND........................................................-0.3V to +30V BST_ to LX_..............................................................-0.3V to +6V REG, DREG_, EN_, RT to SGND..............................-0.3V to +6V PGOOD, FB_, COMP_ to SGND..............................-0.3V to +6V DL_ to PGND_..............
PAGE 3
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing ELECTRICAL CHARACTERISTICS (continued) (VIN = 12V or VIN = VREG = 5V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = TJ = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS OSCILLATOR Switching Frequency Range (Each Converter) fSW fSW minimum, VRT = 0.
PAGE 4
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing ELECTRICAL CHARACTERISTICS (continued) (VIN = 12V or VIN = VREG = 5V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = -40NC to +85NC, unless otherwise noted. Typical values are at TA = TJ = +25NC.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX 0.57 0.60 0.
PAGE 5
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Characteristics (continued) (VIN = 12V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = +25NC, unless otherwise noted. See Figure 10.) CONVERTER 2 OUTPUT VOLTAGE vs. LOAD CURRENT VIN = 12V 3.310 3.308 3.305 3.303 3.300 0.5 VIN = 12V 1.804 1.803 1.0 1.5 2.0 3.0 2.5 1.196 VIN = 5V 1.195 1.194 1.193 1.191 VOUT2 = 1.8V 0 0.5 1.0 1.5 2.0 2.5 VOUT3 = 1.2V 1.190 3.
PAGE 6
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Characteristics (continued) (VIN = 12V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = +25NC, unless otherwise noted. See Figure 10.) OPERATING SUPPLY CURRENT vs.
PAGE 7
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Characteristics (continued) (VIN = 12V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = +25NC, unless otherwise noted. See Figure 10.
PAGE 8
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Characteristics (continued) (VIN = 12V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = +25NC, unless otherwise noted. See Figure 10.) VFB_ vs. TEMPERATURE 120° OUT-OF-PHASE OPERATION MAX15048 toc25 0.60125 VLX1 0V 10V/div 0V VLX2 10V/div VLX3 0V FEEDBACK VOLTAGE (V) 10V/div MAX15048 toc26 0.60250 DRIVERS SWITCHING NO OUTPUT LOAD VIN = 12V 0.60000 0.59875 0.59750 0.59625 0.
PAGE 9
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Characteristics (continued) (VIN = 12V, VDREG_ = VREG, VPGND_ = 0V, CREG = 2.2FF, RRT = 39.2kI, TA = +25NC, unless otherwise noted. See Figure 10.) STARTUP INTO PREBIASED OUTPUT (1.8V PREBIASED) STARTUP INTO PREBIASED OUTPUT (1.2V PREBIASED) MAX15048 toc32 MAX15048 toc31 5V/div VEN1 5V/div VEN1 0V 0V VOUT1 1V/div VOUT1 1V/div 0V 0V 1ms/div 1ms/div LOAD-TRANSIENT RESPONSE (I0UT1 = 1.
PAGE 10
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing FB3 COMP3 PGND1 DL1 DREG1 LX1 DH1 TOP VIEW EN3 Pin Configuration 24 23 22 21 20 19 18 17 16 BST3 25 BST1 DH3 26 15 EN1 LX3 27 14 FB1 13 COMP1 12 PGOOD 11 COMP2 10 FB2 9 EN2 DREG3 28 MAX15048 MAX15049 DL3 29 PGND3 30 4 5 6 7 8 DH2 BST2 SGND 3 LX2 2 DREG2 1 RT REG 32 DL2 + PGND2 IN 31 EP* TQFN (5mm × 5mm) *EXPOSED PAD.
PAGE 11
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Pin Description (continued) PIN NAME 12 PGOOD 13 COMP1 14 FB1 Controller 1 Feedback Regulation Point. Connect to the center tap of a resistive voltage-divider from the converter output to SGND to set the output voltage. The FB1 voltage regulates to 0.6V (typ). 15 EN1 Controller 1 Enable Input. For tracking (MAX15048), EN1 must be above 0.6V, VEN-TH, for the PWM controller to start outputs 1, 2, and 3.
PAGE 12
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Functional Diagrams IN EN1 0.60V 0.55V PGOOD MAX15048 PWM CONTROLLER 1 LDO REG EN SGND 0.60V 0.55V THERMAL SHDN OFF DOWN1 VREF PGPD1 PGPD2 PGPD3 SHDN 0.6V REF CLK1 VREGOK OVL CONFIG DIGITAL SOFT-START AND -STOP OVL1 IMAX1 GM PGND1 OVL_ LX1 OVERLOAD MANAGEMENT CLK1 FB1 BST1 R COMP1 OSC CLK1 S LX1 RAMP DREG1 LEVEL SHIFT CLK2 DH1 Q SET DOMINANT CPWM RT CURRENT-LIMIT SET (69mV TYPICAL) CLK 0.
PAGE 13
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Functional Diagrams (continued) VREF OFF DOWN2/3 CLK2/3 PGND2/3 SHDN DIGITAL SOFT-START AND -STOP OVL CONFIG VREF OVL2/3 VR2/3 IMAX2/3 OVL_ LX2/3 OVERLOAD MANAGEMENT CLK2/3 CURRENT-LIMIT SET (69mV TYPICAL) GM EN2/3 BST2/3 FB2/3 R COMP2/3 SET DOMINANT CPWM CLK2/3 MAX15048 Maxim Integrated S LX2/3 RAMP DREG2/3 LEVEL SHIFT PWM CONTROLLERS 2 AND 3 DH2/3 Q CLK 0.55V 0.
PAGE 14
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Functional Diagrams (continued) IN EN1 0.60V 0.55V PGOOD MAX15049 PWM CONTROLLER 1 LDO REG EN SGND 0.60V 0.55V THERMAL SHDN OFF1 DOWN1 VREF PGPD1 PGPD2 PGPD3 SHDN 0.
PAGE 15
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Functional Diagrams (continued) EN2/3 0.60V 0.55V MAX15049 PWM CONTROLLERS 2 AND 3 PGND2/3 VREF OFF2/3 SHDN LX2/3 CLK2/3 DIGITAL SOFT-START OVL2/3 R GM Q IMAX2/3 SET PREBIAS DOMINANT LATCH S FB2/3 OVERLOAD MANAGEMENT CURRENT-LIMIT SET (69mV TYPICAL) BST2/3 R COMP2/3 DH2/3 Q SET DOMINANT CPWM CLK2/3 CLK2/3 S LX2/3 RAMP DREG2/3 LEVEL SHIFT CLK 0.55V 0.
PAGE 16
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Detailed Description The MAX15048/MAX15049 are triple-output, PWM, stepdown, DC-DC controllers with tracking and sequencing options. The devices operate over the 4.7V to 23V or 5V Q10% input voltage range. Each PWM controller provides an adjustable output down to 0.6V and delivers up to 15A of load current with excellent load and line regulation. The MAX15049 can start into prebiased outputs.
PAGE 17
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing MOSFET Gate Drivers and Internal Boost Switch so that either the master or slave output does not stay on when the other outputs are shorted to ground. When the slave is shorted and enters in hiccup mode, both the master and the other slave soft-stop. When the master is shorted and the part enters hiccup mode, the slaves ratiometrically soft-stop.
PAGE 18
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing MAX15049 Output-Voltage Sequencing (EN_) amplifier. The error transamplifier has an 80dB openloop gain and a 10MHz GBW product. See the Typical Operating Characteristics for a plot of gain and phase vs. frequency. In Figure 1c, when sequencing, the enable input must be above 0.6V for each PWM controller to start. The VOUT_ outputs and EN_ inputs can be daisy-chained to generate power sequencing.
PAGE 19
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing COUNT OF 8 NCL CLR IN CURRENT LIMIT IN INITIATE HICCUP TIMEOUT NHT COUNT OF 3 NCLR CLR Figure 3. Hiccup-Mode Block Diagram just before the beginning of a new PWM cycle, the controller skips that cycle. During severe overload or shortcircuit conditions, the switching frequency of the device appears to decrease because the on-time of the low-side MOSFET extends beyond a clock cycle.
PAGE 20
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing (fSW) is programmable between 200kHz and 1.2MHz (see the Setting the Switching Frequency section). The peak-to-peak inductor current (DIP-P), which reflects the peak-to-peak output ripple, is worst at the maximum input voltage. See the Output-Capacitor Selection section to verify that the worst-case output current ripple is acceptable.
PAGE 21
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Use the following equations to calculate the required ESR, ESL, and capacitance value during a load step: ESR = C OUT = ESL = ∆VESR I STEP I STEP × t RESPONSE ∆VQ ∆VESL × t STEP I STEP t RESPONSE = Compensation Design Guidelines 1 3 × fCO where ISTEP is the load step, tSTEP is the rise time of the load step, tRESPONSE is the response time of the controller, and fCO is the closed-loop crossover frequency of system (see the Comp
PAGE 22
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Below are equations that define the power modulator: G MOD(DC) = fLC = especially the output capacitor. For cost-sensitive applications, use aluminum electrolytic capacitors; for spacesensitive applications, use low ESR tantalum or multilayer ceramic chip (MLCC) capacitors at the output. The higher switching frequencies of the MAX15048/MAX15049 allow the use of MLCC as the primary filter capacitor(s).
PAGE 23
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing The desired (compensated) rolloff follows a -20dB/ decade slope (and commensurate 90° of phase shift), and, in this example, occurs at approximately six times the uncompensated crossover frequency, fCO. In this example, a Type II compensator provides stable closedloop operation, leveraging the +20dB/decade slope of the capacitor’s ESR zero (see Figure 4b).
PAGE 24
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing As with the previous example, the actual gain and phase response is overlaid on the power modulator’s asymptotic gain response. It is readily observed that the more dramatic gain and phase transition at or near the power modulator’s resonant frequency, fLC, vs. the gentler response of the previous example. This is due to the component’s lower parasitics leading to the higher frequency of the inherent ESR zero of the output capacitor.
PAGE 25
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Design procedures for both Type II and Type III compensators are shown below. 2) Select the unity-gain crossover frequency as: f fCO ≤ SW 10 Type II: Compensation when fCO > fZERO, ESR When the fZERO, ESR is lower than fCO and close to fLC, a Type II compensation network provides the necessary closed-loop response. The Type II compensation network provides a midband compensating zero and high-frequency pole (see Figures 5a and 5b).
PAGE 26
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Type III: Compensation when fCO < fZERO, ESR As previously indicated, the position of the output capacitor’s inherent ESR zero is critical in designing an appropriate compensation network. When low-ESR ceramic output capacitors are used, the ESR zero frequency (fZERO, ESR) is usually much higher than unity crossover frequency (fCO). In this case, a Type III compensation network is recommended (see Figure 6a).
PAGE 27
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing Typical Operating Circuits 1 f = 8) Place a second pole ( P2 2π × R F × C CF ) at or below one-half the switching frequency: 1 C CF = π × fSW × R F Figure 7 shows the MAX15048 coincident tracker. Figure 8 is the MAX15048 ratiometric tracker and Figure 9 is the MAX15049 sequencer. Figure 10 shows the evaluation kit schematic configured for the MAX15049 (sequencer).
PAGE 28
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing VOUT2 IN EN2 COMP2 DH3 VOUT3 FB2 PGND2 DL2 LX2 BST2 DH2 IN IN EN1 IN LX3 DH1 BST3 LX1 DL3 MAX15048 PGND3 VOUT1 BST1 DL1 FB3 PGND1 COMP3 DREG3 DREG2 DREG1 PGOOD REG RT SGND FB1 EN3 COMP1 VREG Figure 8.
PAGE 29
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing VOUT2 IN EN2 COMP2 DH3 VOUT3 FB2 PGND2 DL2 BST2 LX2 DH2 IN IN EN1 IN LX3 DH1 BST3 LX1 DL3 MAX15049 PGND3 VOUT1 BST1 DL1 FB3 VOUT2 PGND1 COMP3 DREG3 DREG2 DREG1 PGOOD REG RT SGND FB1 EN3 COMP1 VREG Figure 9.
PAGE 30
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing VOUT2 (1.8V/3A) 24.9kI 12.4kI 330pF 1kI 0.1µF 22µF 22µF 3.3µH VIN 4.99kI FDMC8200 FDMC8200 470µF 22µF 10µF 1µF 22pF 15kI 1500pF 0.1µF 1000pF 2.49kI VIN DH3 EN2 COMP2 FB2 DL2 LX2 BST2 PGND2 IRF7907 VOUT3 (1.2V/6A) DH2 IN 60kI 22µF EN1 VIN 10kI 1µH LX3 100µF 100µF BST3 20I IRF7907 24.9kI DL3 0.1µF 1kI 24.9kI 330pF COMP3 FB1 22pF 10kI 39.2kI 2.2µF DREG3 DREG2 DREG1 VPGOOD 0.
PAGE 31
MAX15048/MAX15049 Triple-Output Buck Controllers with Tracking/Sequencing PWM Controller Applications Information Power Dissipation The 32-pin TQFN thermally enhanced package can dissipate up to 2758.6mW. Calculate power dissipation in the MAX15048/MAX15049 as a product of the input voltage and the total REG output current (IREG).