EVALUATION KIT AVAILABLE
MAX17245
3.5V–36V, 3.5A, Synchronous Buck Converter
With 28μA Quiescent Current and Reduced EMI
General Description
Benefits and Features
The MAX17245 high-efficiency, synchronous step-down
DC-DC converter with integrated MOSFETs operates
over a 3.5V to 36V input voltage range with 42V input
transient protection. The MAX17245 can operate in drop-
out condition by running at 98% duty cycle. This converter
delivers up to 3.5A and generates fixed output voltages of
3.3V/5V, along with the ability to program the output voltage
between 1V to 10V.
●
Eliminates External Components and Reduces
Total Cost
• Integrated High-Side and Low-Side Switch Enables
Synchronous Operation for High Efficiency and
Reduced Cost
• All-Ceramic Capacitor Solution Allows
Ultra-Compact Solution Size
• 220kHz to 2.2MHz Adjustable Frequency with
External Synchronization
The MAX17245 uses a current-mode control architecture
and can operate in the pulse-width modulation (PWM)
or pulse-frequency modulation (PFM) control schemes.
PWM operation provides constant frequency operation at
all loads and is useful in applications sensitive to switching
frequency. PFM operation disables negative inductor
current and additionally skips pulses at light loads for
high efficiency. Under light-load applications, the external
sync pin FSYNC logic input allows the device to operate
in either PFM mode for reduced current consumption or
fixed-frequency PWM (forced-PWM) mode to eliminate
frequency variation to minimize EMI. Fixed-frequency
PWM mode is extremely useful for power supplies
designed for RF transceivers where tight emission control
is necessary.
• Power Good Output and High-Voltage EN Input
Simplify Power Sequencing
●
●
Increases Design Flexibility
• 180° Out-of-Phase Clock Output at SYNCOUT
Enables Cascaded Power Supplies for Increased
Power Output
• Fixed Output Voltage with ±2% Accuracy (5V/3.3V)
or Externally Resistor Adjustable (1V to 10V)
Reduces Power Dissipation
• >90% Peak Efficiency
• PWM and PFM Operation Optimizes Conversion
Efficiency From Heavy to Light Loads
• Automatic LX Slew-Rate Adjustment for Optimum
Efficiency Across Operating Frequency Range
• Low 5μA (typ.) Shutdown Current
• Low 28μA (typ.) Quiescent Current
This device is available in a compact 16-pin (5mm x 5mm)
TQFN package with exposed pad and 16-pin TSSOP.
-40°C to +85°C operation.
●
Operates Reliably
• 42V Input Voltage Transient Protection
• Fixed 8ms Internal Software Start Reduces Input
Inrush Current
Typical Application Circuit
V
BAT
• Cycle-by-Cycle Current limit, Thermal Shutdown
with Automatic Recovery
C
IN2
4.7µF
C
4.7µF
IN3
C
IN1
R
___
0I
• Reduced EMI Emission with Spread-Spectrum
Control
C
0.1µF
BST
SUP
SUPSW
BST
L1
2.2µH
V
OUT
EN
5V AT 3.5A
LX
OSC SYNC PULSE
FSYNC
COMP
V
D1
C
OUT
OUT
22µF
Applications
V
BIAS
R
SNUB*
OUT
FB
C
SNUB*
●
●
●
Distributed Supply Regulation
Wall Transformer Regulation
General-Purpose Point-of-Load
C
COMP1
1000pF
R
MAX17245
FOSC
12kI
C
COMP2
12pF
V
V
BIAS
OUT
R
COMP
20kI
FOSC
BIAS
R
R
SYNCOUT
100I
PGOOD
10kI
PGOOD
POWER-GOOD OUTPUT
180° OUT-OF-PHASE OUTPUT
C
BIAS
1µF
SYNCOUT
PGND AGND
*R
= 1Iand C = 220pF required for
SNUB
SNUB
the following operating conditions:
25V, V 5V, f
Ordering Information/Selector Guide appears at end of data
sheet.
V
BAT
R
P
R 1.8MHz,
OUT SW
FPWM mode enabled
19-8527; Rev 0; 4/16