Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - DC/DC voltage regulator Converter, Boost TQFN 28

Ordering Information continued at end of data sheet.

19-3504; Rev 3; 5/14

General Description

The MAX5073 is a dual-output DC-DC converter with

integrated high-side n-channel power MOSFETs. Each

output can be configured either as a buck converter or a

boost converter. The device is capable of operating from

a wide 5.5V to 23V input voltage range. Each output is

programmable down to 0.8V in the buck mode and up to

28V in the boost mode with an output voltage accuracy

of ±1%. In the buck mode, converter 1 and converter 2

can deliver 2A and 1A, respectively. The output switching

frequency of each converter can be programmed from

200kHz to 2.2MHz to avoid harmonics in a radio power

supply or to reduce the size of the power supply. Each

output operates 180° out-of-phase thus reducing input-

capacitor ripple current, size, and cost. A SYNC input

facilitates external frequency synchronization. Moreover,

a CLKOUT output provides out-of-phase clock signal

with respect to converter 2, allowing four-phase operation

using two MAX5073 ICs in master-slave configuration.

The MAX5073 includes an internal digital soft-start that reduc-

es inrush current, eliminates output-voltage overshoot, and

ensures monotonic rise in output voltage during power-up.

The device includes individual shutdown and a power-good

output for each converter. Protection features include output

short-circuit protection for buck mode and maximum duty-

cycle limit for boost operation, as well as thermal shutdown.

The MAX5073 is available in a thermally enhanced 28-pin

thin QFN package that can dissipate 2.7W at +70°C ambi-

ent temperature. The device is rated for operation over the

-40°C to +85°C extended, or -40°C to +125°C automotive

temperature range.

Applications

● Point-of-Load DC-DC Converters

● Telecom Line Card

● Networking Line Card

● Power-Over-Ethernet Postregulation for PDs

Features

● 4.5V to 5.5V or 5.5V to 23V Input Supply

Voltage Range

● 0.8V (Buck) to 28V (Boost) Output Voltage

● Two Independent Output DC-DC Converters

with Internal Power MOSFETs

● Each Output can be Configured in Buck or Boost

Mode

● I

OUT1

and I

OUT2

of 2A and 1A (Respectively) in

Buck Mode

● 180° Out-of-Phase Operation

● Clock Output for Four Phase Operation

● Switching Frequency Programmable from 200kHz to

2.2MHz

● Digital Soft-Start and Sync Input

● Individual Converter Shutdown and Power-Good

Output

● Short-Circuit Protection (Buck)/Maximum Duty-Cycle

Limit (Boost)

● Thermal Shutdown

● Thermally Enhanced 28-Pin Thin QFN Package

Dissipates up to 2.7W at +70°C

*EP = Exposed pad.

+Denotes lead-free package.

PART TEMP RANGE

PIN-

PACKAGE

CODE

MAX5073ETI -40°C to +125°C

28 Thin QFN-EP*

(5mm x 5mm)

T2855-6

MAX5073ETI+ -40°C to +125°C

28 Thin QFN-EP*

(5mm x 5mm)

T2855-6

21 20 19 18 17 16 15

1 2 3 4 5 6 7

MAX5073

THIN QFN

TOP VIEW

SOURCE1

PGOOD2

SOURCE1

SGND

PGND

SOURCE2

PGOOD1

BST1/VDD1

DRAIN1

EN1

FB1

COMP1

BYPASS

V+

OSC

N.C.

SYNC

COMP2

FB2

EN2

DRAIN2

BST2/VDD2

CLKOUT

MAX5073 2.2MHz, Dual-Output Buck or Boost Converter

with Internal Power MOSFETs

Pin Conguration

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (24 pages)

PAGE 1
EVALUATION KIT AVAILABLE 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs PINPACKAGE PACKAGE CODE MAX5073ETI -40°C to +125°C 28 Thin QFN-EP* (5mm x 5mm) T2855-6 MAX5073ETI+ -40°C to +125°C 28 Thin QFN-EP* (5mm x 5mm) T2855-6 PART TEMP RANGE *EP = Exposed pad. +Denotes lead-free package. Ordering Information continued at end of data sheet.
PAGE 2
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Absolute Maximum Ratings V+ to PGND...........................................................-0.3V to +25V SGND to PGND.....................................................-0.3V to +0.3V VL to SGND..................-0.3V to the lower of +6V or (V+ + 0.3V) BST1/VDD1, BST2/VDD2, DRAIN_, PGOOD2, PGOOD1 to SGND.................................................................-0.
PAGE 3
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Electrical Characteristics (continued) (V+ = VL = 5.2V or V+ = 5.5V to 23V, EN_ = VL, SYNC = GND, IVL = 0mA, PGND = SGND, CBYPASS = 0.22µF, CVL = 4.7µF (ceramic), ROSC = 10kΩ (circuit of Figure 1), TA = TJ = TMIN to TMAX, unless otherwise noted.
PAGE 4
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Electrical Characteristics (continued) (V+ = VL = 5.2V or V+ = 5.5V to 23V, EN_ = VL, SYNC = GND, IVL = 0mA, PGND = SGND, CBYPASS = 0.22µF, CVL = 4.7µF (ceramic), ROSC = 10kΩ (circuit of Figure 1), TA = TJ = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX SYNC = SGND, fSW = 1.
PAGE 5
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Typical Operating Characteristics (V+ = VL = 5.2V, TA = +25°C, unless otherwise noted.) 70 VIN = 12.0V 60 VIN = 16.0V 50 40 30 20 VIN = 12.0V 50 VIN = 16.0V 40 30 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 0.3 0.4 0.5 0.6 0.7 0.8 VIN = 5V 90 80 70 VIN = 3.3V 60 50 40 30 20 VOUT = 2.5V fSW = 2.2MHz 0.2 VOUT = 12V fSW = 2.2MHz 10 0 0.9 1.0 0.02 VL OUTPUT VOLTAGE vs. CONVERTER SWITCHING FREQUENCY 5.
PAGE 6
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Typical Operating Characteristics (continued) (V+ = VL = 5.2V, TA = +25°C, unless otherwise noted.) LINE-TRANSIENT RESPONSE (BUCK CONVERTER) CONVERTER 1 LOAD-TRANSIENT RESPONSE (BUCK CONVERTER) MAX5073 toc10 MAX5073 toc11 VIN 5V/div 0V VOUT1 = 3.3V AC-COUPLED 200mV/div VOUT1 = 3.3V/1.5A AC-COUPLED 200mV/div IOUT1 1A/div VOUT2 = 2.5V/0.
PAGE 7
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Typical Operating Characteristics (continued) (V+ = VL = 5.2V, TA = +25°C, unless otherwise noted.) SYNC 5V/div 0V 1.8 SOURCE1 5V/div 0V 1.4 ROSC = 10kΩ ISTBY (mA) MAX5073 toc16 MAX5073 toc17 V+ STANDBY SUPPLY CURRENT (ISTBY) vs. TEMPERATURE EXTERNAL SYNCHRONIZATION VOUT1 RIPPLE AC-COUPLED 20mV/div CLKOUT 5V/div 0V 1.0 ROSC = 60kΩ 0.6 0.2 200ns/div -7 -40 26 59 92 125 TEMPERATURE (°C) 3.
PAGE 8
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Typical Operating Characteristics (continued) (V+ = VL = 5.2V, TA = +25°C, unless otherwise noted.) VIN = 5.5V fSW = 2.2MHz 2.75 2.50 MAX5073 toc22 MAX5073 toc21 3.00 OUTPUT CURRENT LIMIT (A) FOUR-PHASE OPERATION (SEE FIGURE 3) OUTPUT LOAD CURRENT LIMIT vs. TEMPERATURE SOURCE1 (MASTER) 0V OUTPUT1 2.25 2.00 SOURCE2 (MASTER) 0V OUTPUT2 1.75 SOURCE1 (SLAVE) 0V 1.50 SOURCE2 (SLAVE) 1.25 1.
PAGE 9
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Pin Description (continued) PIN NAME FUNCTION 10 OSC Oscillator Frequency Set Input. Connect a resistor from OSC to SGND (ROSC) to set the switching frequency (see the Oscillator section). Set ROSC for equal to or lower oscillator frequency than the SYNC input frequency when using external synchronization (0.2fSYNC < fOSC < 1.2fSYNC). ROSC is still required when an external clock is connected to the SYNC input.
PAGE 10
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs PGOOD2 OUTPUT2 2.5V/1A OUTPUT1 3.3V/2A VL CLOCK OUT 28 27 26 25 24 23 22 SOURCE2 PGND SGND SOURCE1PGOOD2 PGOOD1 21 1 CLKOUT 2 BST2/VDD2 INPUT SGND EP 4 DRAIN2 5 EN2 BST1/VDD1 20 INPUT DRAIN1 19 3 DRAIN2 ON OFF VL DRAIN1 18 MAX5073 EN1 17 FB1 16 6 FB2 COMP1 15 7 COMP2 SYNC N.C. OSC V+ 8 9 10 11 ON OFF VL BYPASS 13 14 VL 12 SGND SYSTEM CLOCK VIN = 5.
PAGE 11
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Internal Oscillator/Out-of-Phase Operation The internal oscillator generates the 180° out-of-phase clock signal required by each regulator. The internal oscillator frequency is programmable from 400kHz to 4.4MHz using a single 1% resistor at ROSC. Use the following equation to calculate ROSC: R OSC = 25 × 10 9 f OSC where fOSC is the internal oscillator frequency in hertz and ROSC in ohms.
PAGE 12
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs V+ MAX5073 VL LDO CONVERTER 1 VL OSCILLATOR DEAD-TIME CONTROL BST1/VDD1 FREQUENCY FOLDBACK DRAIN1 BYPASS Q N SOURCE1 Q Q PGOOD1 fSW / 4 VREF EN1 VREF DIGITAL SOFT-START FB1 COMP1 0.5VREF 0.92VREF SYNC CKO OSC PGOOD2 MAIN OSCILLATOR BST2/VDD2 VL VDD2 OSCILLATOR EN2 DRAIN2 SOURCE2 CONVERTER 2 FB2 COMP2 Figure 2. Functional Diagram www.maximintegrated.
PAGE 13
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs VIN OUTPUT2 DUTY CYCLE = 50% CLKIN CIN DRAIN2 SOURCE2 SYNC V+ DRAIN1 SOURCE1 OUTPUT1 CLKOUT OUTPUT4 V+ DRAIN2 SOURCE2 DRAIN1 SOURCE1 OUTPUT3 SYNC MASTER SLAVE SYNC CLKOUT (MASTER) CLKOUT (SLAVE) SOURCE1 (MASTER) SYNCPHASE CLKOUTPHASE SOURCE2 (MASTER) SOURCE1 (SLAVE) SOURCE2 (SLAVE) CIN (RIPPLE) Figure 3. Synchronized Controllers www.maximintegrated.
PAGE 14
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Enable The MAX5073 dual converter provides separate enable inputs EN1 and EN2 to individually control or sequence the output voltages. These active-high enable inputs are TTL compatible. Pulling EN_ high ramps up the reference slowly, which provides soft-start at the outputs. Forcing the EN_ low externally disables the individual output and generates a PGOOD_ signal. Use EN1, EN2, and PGOOD1 for sequencing (see Figure 4).
PAGE 15
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Applications Information Setting the Switching Frequency The controller generates the clock signal by dividing down the internal oscillator or the SYNC input signal when driven by an external oscillator. The switching frequency equals half the oscillator frequency (fSW = fOSC/2). The internal oscillator frequency is set by a resistor (ROSC) connected from OSC to SGND. The relationship between fSW and ROSC is: R OSC = 12.
PAGE 16
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Inductor Selection Three key inductor parameters must be specified for operation with the MAX5073: inductance value (L), peak inductor current (IL), and inductor saturation current (ISAT). The minimum required inductance is a function of operating frequency, input-to-output voltage differential and the peak-to-peak inductor current (∆IL).
PAGE 17
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Output Capacitors The allowable output ripple voltage and the maximum deviation of the output voltage during step load currents determines the output capacitance and its ESR. The output ripple is comprised of ∆VQ (caused by the capacitor discharge) and ∆VESR (caused by the ESR of the capacitor). Use low-ESR ceramic or aluminum electrolytic capacitors at the output.
PAGE 18
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Input Capacitor The input current for the boost converter is continuous and the RMS ripple current at the input is low. Calculate the capacitor value and ESR of the input capacitor using the following equations. IN ∆I × D 4 × f SW × ∆VQ ESR = where ∆VESR ∆IL (V − VDS ) × D ∆IL = IN L × f SW where VDS is the total voltage drop across the internal MOSFET plus the voltage drop across the inductor ESR.
PAGE 19
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs = PDC I2 RMS × R DS(ON)MAX where VDS is the drop across the internal MOSFET. See the Electrical Characteristics for the RDS(ON)MAX value. PSW = VO ×IIN ×(t R + t F )× f SW 4 where tR and tF are rise and fall times of the internal MOSFET. The tR and tF are typically 20ns, and can be measured in the actual application. The supply current in the MAX5073 is dependent on the switching frequency.
PAGE 20
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs VIN ESR 0.8 × × GM = VOSC ESR + (2π× f C ×L OUT ) VOUT VOUT CCF where VOSC is a peak-to-peak ramp amplitude equal to 1V. RI The transconductance error amplifier gain is: CI - G E/A = g m ×R F R2 VREF The total loop gain at fC sho be equal to 1 G M × G E/A = 1 or CF RF R1 COMP gM + Figure 7. Type III Compensation Network where: RF = VOSC (ESR + 2π× f C ×L OUT )VOUT CF = 0.
PAGE 21
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs OUTPUT2 PGND PGOOD2 OUTPUT1 PGOOD1 SGND OUTPUT1 3.3V/2A VL 28 27 26 25 24 23 22 SOURCE2 PGND SGND SOURCE1PGOOD2 PGOOD1 21 1 CLKOUT SGND 2 BST2/VDD2 BST1/VDD1 20 EP CLOCK OUT OUTPUT2 12V/0.2A 4 DRAIN2 5 EN2 INPUT DRAIN1 19 3 DRAIN2 ON OFF VL DRAIN1 18 MAX5073 FB1 16 6 FB2 COMP1 15 7 COMP2 SYNC N.C.
PAGE 22
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs 3) Calculate CI for a target crossoverequency, fC: Careful PC board layout is critical to achieve low switching losses and clean, stable operation. This is especially true for dual converters where one channel can affect the other. Refer to the MAX5073 EV kit data sheet for a specific layout example. Use a multilayer board whenever possible for better noise immunity.
PAGE 23
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs Layout Procedure 1) Place the power components first, with ground terminals adjacent (inductor, CIN_, and COUT_). Make all these connections on the top layer with wide, copperfilled areas (2oz copper recommended). 2) Group the gate-drive components (bootstrap diodes and capacitors, and VL bypass capacitor) together near the controller IC.
PAGE 24
MAX5073 2.2MHz, Dual-Output Buck or Boost Converter with Internal Power MOSFETs REVISION HISTORY REVISION NUMBER REVISION DATE 5 5/14 PAGES CHANGED DESCRIPTION Removed automotive reference under Applications section on Page 1 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.