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MAX17634A/MAX17634B/
MAX17634C
4.5V to 36V, 4.25A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
General Description
Benefits and Features
The MAX17634x is a high-efficiency, high-voltage, synchro-
nous step-down DC-DC converter with integrated MOSFETs
operating over an input-voltage range of 4.5V to 36V. It can
deliver up to 4.25A current. The MAX17634 is available in
three variants: MAX17634A, MAX17634B, and MAX17634C.
The MAX17634A and MAX17634B are fixed 3.3V and fixed
5V output voltage parts, respectively. The MAX17634C is
an adjustable output voltage (from 0.9V up to 90% of V )
part. Built-in compensation across the output voltage range
eliminates the need for external components.
● Reduces External Components and Total Cost
• No Schottky–Synchronous Operation
• Internal Compensation Components
• All-Ceramic Capacitors, Compact Layout
● Reduces Number of DC-DC Regulators to Stock
• Wide 4.5V to 36V Input
• Adjustable Output Range from 0.9V up to 90% of V
• 400kHz to 2.2MHz Adjustable Frequency with
External Synchronization
IN
IN
• Available in a 20-Pin, 4mm x 4mm TQFN Package
The MAX17634x features peak-current-mode control
architecture. The device can be operated in forced pulse-
width modulation (PWM), pulse-frequency modulation (PFM),
or discontinuous-conduction mode (DCM) to enable high
efficiency under full-load and lightload conditions. The
MAX17634x offers a low minimum on time that allows high
switching frequencies and a smaller solution size.
● Reduces Power Dissipation
• Peak Efficiency of 94%
• PFM and DCM Modes Enable Enhanced Light-
Load Efficiency
• Auxiliary Bootstrap Supply (EXTVCC) for Improved
Efficiency
• 2.8μA Shutdown Current
The feedback voltage regulation accuracy over -40°C
to +125°C for the MAX17634x is ±1.3%.The device is
available in a compact 20-pin (4mm x 4mm) TQFN package.
Simulation models are available.
● Operates Reliably in Adverse Industrial Environments
• Hiccup-Mode Overload Protection
• Adjustable and Monotonic Startup with Prebiased
Output Voltage
• Built-in Output-Voltage Monitoring with RESET
• Programmable EN/UVLO Threshold
• Overtemperature Protection
• High Industrial -40°C to +125°C Ambient Operating
Temperature Range/-40°C to +150°C Junction
Temperature Range
Applications
● Industrial Control Power Supplies
● General-Purpose Point-of-Load
● Distributed Supply Regulation
● Base Station Power Supplies
● Wall Transformer Regulation
● High-Voltage, Single-Board Systems
Ordering Information appears at end of data sheet.
Typical Application Circuit
V
IN
6.5V–36V
C1
2 x 4.7µF
EN/UVLO
IN
RT
BST
L1
8.2µH
C5
0.1µF
R5
51.1kΩ
MODE/SYNC
V
OUT
LX
FB
5V, 4.25A
C4
2 x 47µF
INTVCC
C3
2.2µF
MAX17634B
SGND
EXTVCC
PGND
C2
5600pF
EP
SS
f
400kHz
SW :
RESET
L1: 8.2µH (XAL6060-822ME)
C1: 4.7µF/50V/X7R/1206 (GRM31CR71H475KA12)
C4: 47uF/10V/X7R/1210 (GRM32ER71A476ME15)
19-100572; Rev 0; 6/19