step-down controller designed to operate with input volt-
ages from 3.5V to 36V while using only 50µA of quies-
cent current at no load. The switching frequency is
adjustable from 220kHz to 1MHz by an external resistor
and can be synchronized to an external clock up to
1.1MHz. The MAX16955 output voltage is pin program-
mable to be either 5V fixed, or adjustable from 1V to
10V. The wide input voltage range, along with its ability
to operate in dropout during undervoltage transients,
makes it ideal for automotive and industrial applications.
The MAX16955 operates in fixed-frequency PWM mode
and low quiescent current skip mode. It features an
enable logic input, which is compatible up to 42V to
disable the device and reduce its shutdown current to
10µA. Protection features include overcurrent limit,
overvoltage, undervoltage, and thermal shutdown with
automatic recovery. The device also features a power-
good monitor to ease power-supply sequencing.
The MAX16955 is available in a thermally enhanced 16-
pin TSSOP package with exposed pad and is specified
for operation over the -40°C to +125°C automotive tem-
perature range.
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Features
Wide 3.5V to 36V Input Voltage Range
42V Input Transient Tolerance
High Duty Cycle During Undervoltage Transients
220kHz to 1MHz Adjustable Switching Frequency
Current-Mode Control Architecture
Adjustable (1V to 10V) Output Voltage with ±2%
Accuracy
Three Operating Modes
50µA Ultra-Low Quiescent Current Skip Mode
Forced Fixed-Frequency Mode
External Frequency Synchronization
Lowest BOM Count, Current-Mode Control
Architecture
Power-Good Output
Enable Input Compatible from 3.3V Logic Level to
42V
Current-Limit, Thermal Shutdown, and
Overvoltage Protection
-40°C to +125°C Automotive Temperature Range
Automotive Qualified
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Typical Operating Circuit
V
BAT
C
IN
SUP
DH
BST
LX
C
BST
L
NH
Applications
Automotive
Industrial
Military
Point of Load
R
COMP
C
COMP2
COMP
Ordering Information
PART
MAX16955AUE/V+
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
16 TSSOP-EP*
C
COMP1
MAX16955
PGOOD
EN
FSYNC
FOSC
R
FOSC
SGND
DL
PGND
CS
OUT
FB
BIAS
C
L
NL
R
SENSE
/V denotes an automotive qualified part.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
V
OUT
5V
C
OUT
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-5781; Rev 1; 9/12
MAX16955
36V, 1MHz Step-Down Controller
with Low Operating Current
ABSOLUTE MAXIMUM RATINGS
SUP and EN to SGND ............................................-0.3V to +42V
LX to PGND ..............................................................-1V to +42V
BST to LX .................................................................-0.3V to +6V
BIAS, FB, PGOOD, FSYNC to SGND .......................-0.3V to +6V
DH to LX ...................................................................-0.3V to +6V
DL to PGND .............................................-0.3V to (V
BIAS
+ 0.3V)
FOSC to SGND ........................................-0.3V to (V
BIAS
+ 0.3V)
CS and OUT to SGND ............................................-0.3V to +11V
*As
per JEDEC51 standard (multilayer board).
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
PGND to SGND .....................................................-0.3V to +0.3V
嵌入式系统
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