Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - DC/DC voltage regulator Holder TQFN 16

General Description

The MAX15036/MAX15037 high-frequency, DC-DC con-

verters with an integrated n-channel power MOSFET

provide up to 3A of load current. The MAX15036

includes an internal power MOSFET to enable the

design of a nonsynchronous buck or boost topology

power supply. The MAX15037 is for the design of a

synchronous buck topology power supply. These

devices operate from a 4.5V to 5.5V or 5.5V to 23V

input voltage and offer the ability to set the switching

frequency from 200kHz to 2.2MHz with an external

resistor. The voltage-mode architecture with a peak

switch current-limit scheme provides stable operation

up to a 2.2MHz switching frequency. The MAX15036

includes a clock output for driving a second DC-DC

converter 180° out-of-phase and a power-on-reset

(RESET) output. The MAX15037 includes a power-good

output and a synchronous rectifier driver to drive an

external low-side MOSFET in the buck converter config-

uration for high efficiency.

The MAX15036/MAX15037 protect against overcurrent

conditions by utilizing a peak current limit as well as

overtemperature shutdown providing a very reliable

and compact power source for point-of-load regulation

applications. Additional features include synchroniza-

tion, internal digital soft-start, and an enable input. The

MAX15036/MAX15037 are available in a thermally

enhanced, space-saving 16-pin TQFN (5mm x 5mm)

package and operate over the -40°C to +125°C tem-

perature range.

Applications

xDSL Modem Power Supplies

Automotive Radio Power Supplies

Servers and Networks

IP Phones/WLAN Access Points

Features

o 4.5V to 5.5V or 5.5V to 23V Input Voltage Range

o Output Voltage Adjustable Down to 0.6V (Buck) or

Up to 28V (Boost)

o 3A Output Current

o Synchronous Rectifier Driver Output (MAX15037)

for Higher Efficiency

o Resistor-Programmable Switching Frequency

from 200kHz to 2.2MHz

o External Synchronization and Enable (On/Off)

Inputs

o Clock Output for Driving Second Converter 180°

Out-Of-Phase (MAX15036)

o Integrated 150mΩ High-Side n-Channel Power

MOSFET

o Power-On-Reset Output (MAX15036)/Power-Good

Output (MAX15037)

o Short-Circuit Protection (Buck)/Maximum Duty-

Cycle Limit (Boost)

o Thermal-Shutdown Protection

o Thermally Enhanced 16-Pin TQFN Package

Dissipates 2.7W

MAX15036/MAX15037

2.2MHz, 3A Buck or Boost Converters

with an Integrated High-Side Switch

________________________________________________________________

Maxim Integrated Products

DRAIN

PGND

CKO

SOURCE

RESET

12 11 9

BST/VDD

V+

BYPASS

OSC

MAX15036

COMP SGND

SYNC

EP*

*EXPOSED PAD.

THIN QFN

5mm x 5mm

TOP VIEW

Pin Configurations

Ordering Information

19-4222; Rev 0; 7/08

For pricing delivery, and ordering information please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Pin Configurations continued at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX15036ATE+ -40°C to +125°C 16 TQFN-EP*

MAX15037ATE+ -40°C to +125°C 16 TQFN-EP*

Selector Guide

PART CONFIGURATION FEATURES

MAX15036ATE

Nonsynchronous

Buck or Boost

RESET Output,

Clock Output

MAX15037ATE Synchronous Buck

PGOOD Output,

Synchronous FET

Driver

Denotes a lead-free/RoHS-compliant package.

EP = Exposed pad.

Summary of content (25 pages)

PAGE 1
9-4222; Rev 0; 7/08 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Features The MAX15036/MAX15037 high-frequency, DC-DC converters with an integrated n-channel power MOSFET provide up to 3A of load current. The MAX15036 includes an internal power MOSFET to enable the design of a nonsynchronous buck or boost topology power supply. The MAX15037 is for the design of a synchronous buck topology power supply. These devices operate from a 4.5V to 5.5V or 5.
PAGE 2
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch ABSOLUTE MAXIMUM RATINGS V+ to PGND............................................................-0.3V to +25V BST/VDD, DRAIN to SGND ....................................-0.3V to +30V SGND to PGND .....................................................-0.3V to +0.3V BST/VDD to SOURCE...............................................-0.3V to +6V SOURCE to SGND..................................................-0.
PAGE 3
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch (V+ = VL = 5V or V+ = 5.5V to 23V, VEN = 5V, TA = TJ = -40°C to +125°C, unless otherwise noted. Circuits of Figures 5 and 6. Typical values are at TA = TJ = +25°C.
PAGE 4
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch ELECTRICAL CHARACTERISTICS (continued) (V+ = VL = 5V or V+ = 5.5V to 23V, VEN = 5V, TA = TJ = -40°C to +125°C, unless otherwise noted. Circuits of Figures 5 and 6. Typical values are at TA = TJ = +25°C.
PAGE 5
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch 60 40 30 VOUT = 2.5V 40 30 0.5 1.0 1.5 2.0 2.5 0 0 3.0 OUTPUT CURRENT (A) 0.5 1.0 1.5 2.0 OUTPUT CURRENT (A) 2.5 MAX15037 SYNCHRONOUS EFFICIENCY vs. OUTPUT CURRENT (VIN = 12V, fSW = 330kHz, L = 15μH) VOUT = 3.3V 90 0.5 1.0 1.5 2.0 OUTPUT CURRENT (A) 80 VOUT = 3.3V 70 2.5 3.0 60 VOUT = 2.5V 80 EFFICIENCY (%) EFFICIENCY (%) 85 0 MAX15037 SYNCHRONOUS EFFICIENCY vs. OUTPUT CURRENT (VIN = 12V, fSW = 2.
PAGE 6
Typical Operating Characteristics (continued) (V+ = VL = 5.2V, TA = +25°C, Figures 5 and 6, unless otherwise noted.) 2350 2100 0.20 V+ = 5V 0.15 FREQUENCY (kHz) FREQUENCY (kHz) V+ = 5.25V 1000 1600 1350 850 600 0.05 350 600 1100 1600 0 2100 ROSC = 20kΩ ROSC = 40kΩ 100 100 100 ROSC = 10kΩ 1100 0.10 0 ROSC = 6.04kΩ 1850 0.30 0.25 10 20 30 40 50 60 70 -40 10 60 TEMPERATURE (°C) RESISTANCE (kΩ) SWITCHING FREQUENCY (kHz) MAX15037 LOAD-TRANSIENT RESPONSE (IOUT = 0.
PAGE 7
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch MAX15037 SOFT-START AND SHUTDOWN (IOUT = 2A) RESET TIMEOUT (MAX15036) VIN STARTUP WAVEFORM (EN CONNECTED TO VL) (MAX15037) MAX15036 toc15 MAX15036 toc17 MAX15036 toc16 VEN 5V/div VIN = 12V VIN 10V/div VOUT 2V/div 1V/div VEN VPGOOD 5V/div 0V 5V/div VEN 5V/div VOUT 2V/div 5V/div VRESET 0V VIN 10V/div 1ms/div 40ms/div 1ms/div MAX15036 EXTERNALLY SYNCHRONIZED SWITCHING WAVEFORM STANDBY CURRENT vs.
PAGE 8
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch MAX15036/MAX15037 Pin Description PIN NAME FUNCTION 1, 2 DRAIN Internal Power MOSFET Drain Connection. Buck converter operation—use the MOSFET as a high-side switch and connect DRAIN to the input supply. Boost converter operation (MAX15036 only)—use the MOSFET as a low-side switch and connect DRAIN to the inductor and diode junction. 3 COMP Transconductance Error Amplifier Output.
PAGE 9
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch MAX15036/MAX15037 V+ DRAIN VL LDO VL = 5.2V SYNC RSENSE CKO CURRENT-LIMIT COMPARATOR OSCILLATOR OSC 4-PULSE SKIP BST/VDD 2V R 150mΩ 1V Q N2 BYPASS PWM COMPARATOR SOURCE Q ADAPTIVE BBM VREF 20Ω N3 fSW/4 PGND EN DIGITAL SOFT-START gm VREF = 0.6V FB COMP SGND 200mV RESET N1 MAX15036 0.925 x VREF 200ms DELAY Figure 1.
PAGE 10
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch V+ DRAIN VL LDO VL = 5.2V SYNC RSENSE CURRENT-LIMIT COMPARATOR OSCILLATOR OSC 4-PULSE SKIP BST/VDD 2V R 150mΩ 1V Q N2 BYPASS PWM COMPARATOR SOURCE Q ADAPTIVE BBM 20Ω N3 fSW/4 VL VREF DL PGND EN DIGITAL SOFT-START gm VREF = 0.6V FB COMP SGND 200mV PGOOD N1 MAX15037 0.925 x VREF Figure 2.
PAGE 11
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch PWM Controller The MAX15036/MAX15037 use a pulse-width modulation (PWM) voltage-mode control scheme. The MAX15036 is a nonsynchronous converter and uses an external low-forward-drop Schottky diode for rectification. The MAX15037 is a synchronous converter and drives a low-side, low-gate-charge MOSFET for higher efficiency.
PAGE 12
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Enable EN is an active-high input that turns the MAX15036/ MAX15037 on and off. EN is a TTL-logic input with 2.0V and 0.8V logic-high and low levels, respectively. When EN is asserted high, the internal digital soft-start cycle slowly ramps up the internal reference and provides some soft-start at the output. Hysteresis provides immunity to the glitches during logic turn-on of the converter.
PAGE 13
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Power-On Reset (RESET) (MAX15036 Only) RESET is an active-low open-drain output that goes low when VOUT falls below 92.5% of its nominal set point. RESET goes high impedance when VOUT rises above 92.5% of its nominal set point, the soft-start period is complete, and the 200ms (typ) timeout period has elapsed. Connect a pullup resistor from RESET to a logic voltage or to VL.
PAGE 14
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Effective Input Voltage Range The MAX15036/MAX15037 can operate with input supplies ranging from 4.5V to 5.5V or 5.5V to 23V. The input voltage range (V+) can be constrained to a minimum by the duty-cycle limitations and to a maximum by the on-time limitation. The minimum input voltage is determined by: V + VDROP1 VIN _ MIN = OUT + VDROP2 − VDROP1 DMAX D MAX is the maximum duty cycle of 87.5% (typ).
PAGE 15
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch ESR = CIN = ΔVESR ΔIP−P ⎞ ⎛ ⎜IOUT + ⎟ ⎝ 2 ⎠ IOUT × D(1− D) ΔVQ × fSW where ΔIP−P = (VIN − VOUT ) × VOUT VIN × fSW × L V D = OUT VIN and where IOUT is the output current, D is the duty cycle, and f SW is the switching frequency. Use additional input capacitance at lower input voltages to avoid possible undershoot below the UVLO threshold during transient loading.
PAGE 16
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Inductor Choose the minimum inductor value so the converter remains in continuous mode operation at minimum output current (IOUTMIN). LMIN = V 2IN × D × η 2 × fSW × VOUT × IOUTMIN where V + VD − VIN D = OUT VOUT + VD − VDS and IOUTMIN = 0.25 x IOUT. The V D is the forward voltage drop of the external Schottky diode, D is the duty cycle, and VDS is the voltage drop across the internal switch.
PAGE 17
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch D IRMS_MOSFET = (I DC +I PK +(IDC × IPK )) × MAX 3 2 2 V ×I IIN = OUT OUT VIN × η ΔIP − P = ( VIN − VDROP ) × D L × fSW IDC = IIN − ΔIP − P 2 IPK = IIN + ΔIP − P 2 The power lost due to switching the internal power MOSFET is: PSW = VIN × IOUT × (tR + tF ) × fSW 4 tR and tF are the rise and fall times of the internal power MOSFET measured at SOURCE.
PAGE 18
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch If fZESR is lower than fC and close to fLC, use a Type II compensation network where RFCF provides a midband zero (fmid,zero) and RFCCF provides a high-frequency pole. Calculate the modulator gain (GM) at the crossover frequency.
PAGE 19
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch MAX15036/MAX15037 VOUT R1 COMP gm R2 VREF CCF RF CF Figure 3. Type II Compensation Network VOUT CCF RA R1 CF RF CA gm R2 COMP VREF Figure 4.
PAGE 20
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch Boost Converter Compensation The boost converter compensation gets complicated due to the presence of a right-half-plane zero fZERO,RHP. The right-half-plane zero causes a drop in-phase while adding positive (+1) slope to the gain curve. It is important to drop the gain significantly below unity before the RHP frequency. Use the following procedure to calculate the compensation components. (See Figure 4.
PAGE 21
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch 3) 4) 5) 6) Ensure that the feedback connection from FB to COUT is short and direct. 7) Route high-speed switching nodes (BST/VDD, SOURCE) away from the sensitive analog areas (BYPASS, COMP, FB, and OSC). Use internal PCB layers for SGND as EMI shields to keep radiated noise away from the IC, feedback dividers, and the analog bypass capacitors.
PAGE 22
PGND VIN + Figure 5. MAX15036 Buck Configuration ______________________________________________________________________________________ SGND R2 6.04kΩ 1% PGND R3 750Ω 1% R1 27.4kΩ 1% C5 330pF VOUT C1 47μF 35V VIN C8 0.1μF C6 0.1μF VL C9 4.7μF R5 6.04kΩ 1% VIN C3 1200pF R4 10kΩ 1% C7 0.
PAGE 23
PGND VIN + SGND R2 6.04kΩ 1% R3 750Ω 1% R1 27.4kΩ 1% PGND C5 330pF VOUT C1 47μF 35V VIN C8 0.1μF C6 0.1μF VL C9 4.7μF R5 6.04kΩ 1% VIN C3 1200pF R4 10kΩ 1% C7 0.22μF C4 22pF C2 10μF 10 8 5 6 11 7 4 3 2 1 SGND VL OSC EN DL SOURCE BST/VDD SYNC PGOOD MAX15037 BYPASS PGND V+ FB COMP DRAIN DRAIN 9 12 15 13 14 16 R6 4.7Ω R7 15Ω JU1 R8 10kΩ VL 3 N1 C10 0.1μF D1 VL R10 10kΩ 4 1 256 R9 10kΩ D2 C11 22μF L1 4.7μH C12 0.
PAGE 24
MAX15036/MAX15037 2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch VL VOUT R8 10kΩ JU1 VOUT C12 0.1μF PGND C11 22μF EN 16 D2 VIN PGND C1 47μF 35V R9 10kΩ L1 4.7μH VIN 1 2 C2 10μF DRAIN SYNC 14 C4 22pF R4 22.1kΩ 1% C3 2200pF R2 6.04kΩ 1% COMP SOURCE 4 FB CKO VIN OSC 7 C6 0.1μF 11 6 C7 0.22μF R10 10kΩ VL BST/VDD 15 C10 0.1μF 12 9 5 PGND BYPASS SGND PGND R5 6.04kΩ 1% V+ VL VL SGND 8 10 C9 4.7μF C8 0.1μF Figure 7.
PAGE 25
2.2MHz, 3A Buck or Boost Converters with an Integrated High-Side Switch CIN V+ V+ DRAIN DRAIN OUTPUT1 OUTPUT2 SOURCE SOURCE DUTY CYCLE = 50% SYNC CLKIN SYNC CLKOUT SLAVE MASTER SYNC CLKOUT (MASTER) SOURCE (MASTER) SYNCPHASE SOURCE (SLAVE) CLKOUTPHASE Figure 8. Synchronized Converters Chip Information Pin Configurations (continued) SOURCE PGND SGND DL TOP VIEW PROCESS: BiCMOS 12 11 10 9 SYNC 13 PGOOD 14 MAX15037 BST/VDD 15 *EXPOSED PAD.