IC BUCK SYNC ADJ 3A 16QSOP

MAX15046AAEE+

Manufacturer Part NumberMAX15046AAEE+
DescriptionIC BUCK SYNC ADJ 3A 16QSOP
ManufacturerMaxim Integrated Products
TypeStep-Down (Buck)
MAX15046AAEE+ datasheet
 


Specifications of MAX15046AAEE+

Internal Switch(s)NoSynchronous RectifierYes
Number Of Outputs1Voltage - Output0.6 ~ 34 V
Current - Output3AFrequency - Switching100kHz ~ 1MHz
Voltage - Input4.5 ~ 40 VOperating Temperature-40°C ~ 125°C
Mounting TypeSurface MountPackage / Case16-QSOP
Power - Output771.5mWLead Free Status / RoHS StatusLead free / RoHS Compliant
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19-4719; Rev 1; 2/10
40V, High-Performance, Synchronous
General Description
The MAX15046 synchronous step-down controller oper-
ates from a 4.5V to 40V input voltage range and gener-
ates an adjustable output voltage from 85% of the input
voltage down to 0.6V, supporting loads up to 25A. The
device allows monotonic startup into a prebiased bus
without discharging the output and features adaptive
internal digital soft-start.
The MAX15046 offers the ability to adjust the switching
frequency from 100kHz to 1MHz with an external resis-
tor. The MAX15046’s adaptive synchronous rectifica-
tion eliminates the need for an external freewheeling
Schottky diode. The device also utilizes the external
low-side MOSFET’s on-resistance as a current-sense
element, eliminating the need for a current-sense resis-
tor. This protects the DC-DC components from damage
during output overloaded conditions or output short-
circuit faults without requiring a current-sense resistor.
Hiccup-mode current limit reduces power dissipation
during short-circuit conditions. The MAX15046 includes
a power-good output and an enable input with precise
turn-on/turn-off threshold, which can be used for input
supply monitoring and for power sequencing.
Additional protection features include sink-mode current
limit, and thermal shutdown. Sink-mode current limit pre-
vents reverse inductor current from reaching dangerous
levels when the device is sinking current from the output.
The MAX15046 is available in a 16-pin QSOP or 16-pin
QSOP-EP package and operates over the -40NC to +125NC
temperature range.
Pin Configurations appear at end of data sheet.
4.5V TO 40V
V
IN
ON
OFF
R4
C5
R3
C7
_______________________________________________________________ Maxim Integrated Products 1
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.
Input Voltage Ranges from 4.5V to 40V or 5V
S
Q10%
Adjustable Outputs from 0.85 x V
S
Adjustable Switching Frequency (100kHz to 1MHz)
S
with Q10% (1MHz) Accuracy
Adaptive Internal Digital Soft-Start
S
Up to 25A Output Capability
S
Cycle-by-Cycle Valley-Mode Current Limit with
S
Adjustable, Temperature-Compensated Threshold
(30mV to 300mV)
Monotonic Startup into Prebiased Output
S
Q1% Accurate Voltage Reference
S
3A-Peak Gate Drivers
S
Hiccup-Mode Short-Circuit Protection
S
Overtemperature Shutdown
S
Power-Good (PGOOD) Output and Enable Input
S
(EN) with Q5% Accurate Threshold
Thermally Enhanced 16-Pin QSOP Package
S
Industrial Power Supplies (PLC, Industrial
Computers, Fieldbus Components, Fieldbus
Couplers)
Telecom Power Supplies
Base Stations
PART
MAX15046AAEE+
MAX15046BAEE+
+ Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
C1
IN
CSP
MAX15046
V
DH
CC
PGOOD
LX
C2
EN
BST
DL
LIM
D1
COMP
DRV
C4
R5
FB
PGND
C6
RT
GND
R1
R3
R2
Buck Controller
Features
Down to 0.6V
IN
Applications
Ordering Information
TEMP RANGE
PIN-PACKAGE
°
°
16 QSOP
-40
C to +125
C
°
°
16 QSOP-EP*
-40
C to +125
C
Typical Operating Circuit
Q1
L1
0.6V TO 0.85V x V
IN
V
OUT
C3
Q2

MAX15046AAEE+ Summary of contents

  • Page 1

    ... Power-Good (PGOOD) Output and Enable Input S (EN) with Q5% Accurate Threshold Thermally Enhanced 16-Pin QSOP Package S Industrial Power Supplies (PLC, Industrial Computers, Fieldbus Components, Fieldbus Couplers) Telecom Power Supplies Base Stations PART MAX15046AAEE+ MAX15046BAEE+ + Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad CSP MAX15046 ...

  • Page 2

    High-Performance, Synchronous Buck Controller ABSOLUTE MAXIMUM RATINGS IN to GND ..............................................................-0.3V to +45V V to GND ..................... -0.3V to lower EN, DRV to GND .....................................................-0.3V to +6V PGOOD to GND ....................................................-0.3V to +45V PGND to GND ...

  • Page 3

    High-Performance, Synchronous ELECTRICAL CHARACTERISTICS (continued 24V 5V GND PGND noted. Typical values are +25NC.) (Note 2) A PARAMETER V Minimum Voltage COMP-RAMP COMP Source/Sink Current ENABLE (EN) ...

  • Page 4

    High-Performance Synchronous Buck Controller ELECTRICAL CHARACTERISTICS (continued 24V 5V GND PGND noted. Typical values are +25NC.) (Note 2) A PARAMETER DL Peak Current DH, DL Break-Before-Make Time ...

  • Page 5

    High-Performance Synchronous (V = 24V +25NC, unless otherwise noted EFFICIENCY vs. LOAD CURRENT (V = 24V) IN 100 3.3V V OUT = 1.8V 60 OUT V = 1.2V OUT V ...

  • Page 6

    High-Performance, Synchronous Buck Controller (V = 24V +25NC, unless otherwise noted LIM REFERENCE CURRENT vs. TEMPERATURE -40 -25 - ...

  • Page 7

    High-Performance, Synchronous (V = 24V +25NC, unless otherwise noted STARTUP WITH PREBIASED OUTPUT (2V) MAX15046 toc15c 24V IN 10V/div 2V V OUT 2V/div PGOOD 5V/div V = 3.3V OUT 4ms/div DH_ AND DL_ DISOVERLAP MAX15046 ...

  • Page 8

    High-Performance, Synchronous Buck Controller PIN NAME Regulator Input. Connect to the input rail of the buck converter. Bypass IN to PGND with a 100nF 1 IN minimum ceramic capacitor. When operating in the 5V Q10% range, connect IN to ...

  • Page 9

    High-Performance, Synchronous VREF OSCILLATOR RT ENABLE COMPARATOR EN EN_INT VREF BGAP_OK BANDGAP BGAP_OK V_BGAP OK GENERATOR VIN_OK INTERNAL V_BGAP VOLTAGE REGULATOR VL_OK UVLO BGAP_OK VDRV_OK DRV BGAP_OK UVLO V_DRV THERMAL VIN_OK SHUTDOWN SHUTDOWN AND ILIM ...

  • Page 10

    High-Performance, Synchronous Buck Controller Detailed Description The MAX15046 synchronous step-down controller oper- ates from a 4.5V to 40V input-voltage range and gener- ates an adjustable output voltage from 85% of the input- voltage down to 0.6V while supporting loads ...

  • Page 11

    High-Performance, Synchronous to function properly. The stray impedance in the gate discharge path can cause the sense circuitry to interpret the MOSFET gate as “off” while the V is still high. To minimize stray impedance, use very short, wide ...

  • Page 12

    High-Performance, Synchronous Buck Controller When the valley current limit is reached during soft-start, the MAX15046 regulates to the output impedance times the limited inductor current and turns off after 4096 clock cycles. When starting up into a large capacitive ...

  • Page 13

    High-Performance, Synchronous MAX15046 stops both DL and DH drivers and waits for 4096 switching cycles (hiccup timeout delay) before attempting a new soft-start sequence. The hiccup-mode protection remains active during the soft-start time. Undervoltage Lockout The MAX15046 provides an ...

  • Page 14

    High-Performance, Synchronous Buck Controller Setting the Switching Frequency An external resistor connecting RT to GND sets the switching frequency (f ). The relationship between f SW and R is: RT 17.3 10 × ...

  • Page 15

    High-Performance, Synchronous Connect an external resistor (R LIM to adjust the current-limit threshold, which is temper- ature-compensated with a temperature coefficient of 2300ppm/NC. The relationship between the current-limit threshold (V ) and R is: ITH LIM × ...

  • Page 16

    High-Performance, Synchronous Buck Controller Compensation Design The MAX15046 provides an internal transconductance amplifier with the inverting input and the output available for external frequency compensation. The flexibility of external compensation offers wide selection of output filtering components, especially the ...

  • Page 17

    High-Performance, Synchronous The total loop gain, which is the product of the modulator gain and the error-amplifier gain at f × GAIN GAIN 1 MOD ESR IN FB × × ...

  • Page 18

    High-Performance, Synchronous Buck Controller So π × R × 0 The gain of the modulator (GAIN the pulse-width modulator, LC filter, feedback divider, and associated circuitry at crossover frequency is: V ...

  • Page 19

    High-Performance, Synchronous OUT REF Figure 4. Type III Compensation Network overall thermal budget. Ensure that the DL gate driver can drive the low-side ...

  • Page 20

    High-Performance, Synchronous Buck Controller PCB Layout Guidelines Careful PCB layout is critical to achieve clean and stable operation. The switching power stage requires particular attention. Follow these guidelines for good PCB layout: 1) Place decoupling capacitors as close as ...

  • Page 21

    High-Performance, Synchronous V IN +24V C1 100FF R7 51kI ON OFF R9 32.4kI C13 68pF R8 C15 22.6kI 15pF C14 1500pF Q1: VISHAY SILICONIX Si7850DP Q2: VISHAY SILICONIX Si7460DP D1: DIODES INC. ZHCS506 L1: VISHAY IHLP-4040PZ ER1R5M C1: PANASONIC ...

  • Page 22

    High-Performance, Synchronous Buck Controller V IN +4.5V TO +5. PGOOD ENABLE AUX +4.5V TO +5. PGOOD ENABLE _____________________________________________________________________________________ Typical Application Circuits (continued) TYPICAL ...

  • Page 23

    High-Performance, Synchronous TOP VIEW + PGOOD 3 MAX15046A EN 4 LIM 5 COMP QSOP Chip Information PROCESS: BiCMOS ______________________________________________________________________________________ 16 CSP PGOOD BST ...

  • Page 24

    ... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 24 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 2010 Maxim Integrated Products © ...