19-5481; Rev 4; 3/12
IT
TION K
VALUA
E
BLE
AVAILA
2.1MHz, High-Voltage,
600mA Mini-Buck Converter
General Description
Features
o
Wide +3.5V to +28V Input Voltage Range
o
Tolerates Input Voltage Transients to +42V
o
600mA Minimum Output Current with Overcurrent
Protection
o
Fixed Output Voltages (+3.3V and +5V)
o
2.1MHz Switching Frequency with Three Modes of
Operation
25µA Ultra-Low Quiescent Current SKIP Mode
Forced Fixed-Frequency Operation
External Frequency Synchronization
o
Optional Spread-Spectrum Frequency Modulation
o
Power-Good Output
o
Enable-Pin Compatible from +3.3V Logic Level to
+42V
o
o
o
o
Thermal Shutdown Protection
-40°C to +125°C Automotive Temperature Range
10-Pin TDFN-EP or 16-Pin TSSOP-EP Packages
AEC-Q100 Qualified
MAX16904
The MAX16904 is a small, synchronous buck converter
with integrated high-side and low-side switches. The
device is designed to deliver 600mA with input voltages
from +3.5V to +28V while using only 25μA quiescent
current at no load. Voltage quality can be monitored by
observing the PGOOD signal. The MAX16904 can oper-
ate in dropout by running at 97% duty cycle, making it
ideal for automotive and industrial applications.
The MAX16904 operates at a 2.1MHz frequency, allow-
ing for small external components and reduced output
ripple. It guarantees no AM band interference. SYNC
input programmability enables three frequency modes
for optimized performance: forced fixed-frequency
operation, SKIP mode (ultra-low quiescent current of
25μA), and synchronization to an external clock. The
MAX16904 can be ordered with spread-spectrum fre-
quency modulation, designed to minimize EMI-radiated
emissions due to the modulation frequency.
The MAX16904 is available in a thermally enhanced,
3mm x 3mm, 10-pin TDFN package or a 16-pin TSSOP
package. The MAX16904 operates over the -40°C to
+125°C automotive temperature range.
Applications
Automotive
Industrial
Military
High-Voltage Input-Power DC-DC Applications
MAX16904RAUE__/V+
MAX16904SATB__/V+
MAX16904SAUE__/V+
PART
MAX16904RATB__/V+
Ordering Information
SPREAD
TEMP PIN-
SPECTRUM RANGE PACKAGE
Disabled
Disabled
Enabled
Enabled
-40°C to
10 TDFN-EP*
+125°C
-40°C to
16 TSSOP-EP*
+125°C
-40°C to
10 TDFN-EP*
+125°C
-40°C to
16 TSSOP-EP*
+125°C
Note:
Insert the desired suffix letters (from
Selector Guide)
into
the blanks to indicate the output voltage. Alternative output volt-
ages available upon request.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
*EP
= Exposed pad.
Selector Guide appears at end of data sheet.
________________________________________________________________
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.
2.1MHz, High-Voltage,
600mA Mini-Buck Converter
MAX16904
Typical Operating Circuits
33kΩ
SUP
4.7μF
EN
*
MAX16904_50/V+
SYNC
BST
GND
V
BAT
LEVEL
SIGNAL
0.1μF
4.7μH
5V AT 600mA
10μF
PGND
OUTS
LX
PGOOD
20kΩ
BIAS
2.2μF
33kΩ
SUP
4.7μF
EN
*
MAX16904_33/V+
SYNC
BST
GND
V
BAT
LEVEL
SIGNAL
0.1μF
3.3μH
3.3V AT 600mA
10μF
PGND
OUTS
LX
PGOOD
20kΩ
BIAS
2.2μF
*
PLACE INPUT SUPPLY CAPACITORS AS CLOSE AS POSSIBLE TO THE SUP PIN. SEE THE
APPLICATIONS INFORMATION
SECTION FOR MORE DETAILS.
2
_______________________________________________________________________________________
2.1MHz, High-Voltage,
600mA Mini-Buck Converter
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND.)
SUP, EN..................................................................-0.3V to +42V
BST to LX..................................................................-0.3V to +6V
LX..............................................................-0.3V to (V
SUP
+ 0.3V)
BST .........................................................................-0.3V to +47V
OUTS ......................................................................-0.3V to +12V
SYNC, PGOOD, BIAS............................................-0.3V to +6.0V
PGND to GND .......................................................-0.3V to +0.3V
LX Continuous RMS Current .................................................1.0A
OUTS Short-Circuit Duration ......................................Continuous
ESD Protection
Human Body Model .........................................................±2kV
Machine Model ..............................................................±200V
Continuous Power Dissipation (T
A
= +70°C)
TDFN (derate 24.4 mW/°C above +70°C)......................1951mW
TSSOP (derate 26.1 mW/°C above +70°C) ...................2089mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
MAX16904
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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TDFN
Junction-to-Ambient Thermal Resistance (θ
JA
) ...........41°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ..................9°C/W
TSSOP
Junction-to-Ambient Thermal Resistance (θ
JA
) ........38.3°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ..................3°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(V
SUP
= +14V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage Range
SYMBOL
V
SUP
(Note 2)
t < 1s
EN = low
Supply Current
I
SUP
V
UVLO
V
UVLO,HYS
V
BIAS
I
BIAS
V
OUT
= 5V, fixed frequency
V
OUT,5V
Voltage Accuracy
V
OUT,3.3V
V
OUT
= 5V, SKIP mode
(Note 3)
V
OUT
= 3.3V, fixed frequency
V
OUT
= 3.3V, SKIP mode
(Note 3)
6V V
SUP
18V,
I
LOAD
= 0 to 600mA,
T
A
= -40°C to
+125°C
EN = high, no load
EN = high, continuous, no switching
UV Lockout
Bias Voltage
Bias Current Limit
BUCK CONVERTER
-2.0%
-2.0%
-2.0%
-2.0%
5
5
3.3
3.3
+2.5%
+4%
+2.5%
+4%
V
Bias rising
Hysteresis
+5.5V
V
SUP
+42V
10
2.8
4
25
1
3
0.4
5
3.2
CONDITIONS
MIN
3.5
TYP
MAX
28
42
8
35
UNITS
V
μA
mA
V
V
mA
_______________________________________________________________________________________
3
2.1MHz, High-Voltage,
600mA Mini-Buck Converter
MAX16904
ELECTRICAL CHARACTERISTICS (continued)
(V
SUP
= +14V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
SKIP-Mode Peak Current
High-Side DMOS RDS
ON
Low-Side DMOS RDS
ON
DMOS Peak Current-Limit
Threshold
Soft-Start Ramp Time
LX Rise Time
Minimum On-Time
PWM Switching Frequency
SYNC Input Frequency Range
Spread-Spectrum Range
PGOOD
PGOOD Threshold
PGOOD Debounce
PGOOD High Leakage Current
PGOOD Output Low Level
LOGIC LEVELS
EN Level
EN Input Current
SYNC Switching Threshold
SYNC Internal Pulldown
THERMAL PROTECTION
Thermal Shutdown
Thermal Shutdown Hysteresis
T
SHDN
T
SHDN,HYS
175
15
°C
°C
V
IH,EN
V
IL,EN
I
IN,EN
V
IH,SYNC
V
IL,SYNC
R
PD,SYNC
200
V
EN
= V
SUP
= +42V, T
A
= +25°C
1.4
0.4
2.4
0.6
1
V
μA
V
k
V
THR,PGD
V
THF,PGD
t
DEB
I
LEAK,PGD
V
OUT,PGD
T
A
= +25°C
Sinking 1mA
V
OUT
rising
V
OUT
falling
88
93
91
10
1
0.4
94
%
μs
μA
V
SYMBOL
I
SKIP
R
ON,HS
R
ON,LS
I
MAX
t
SS
t
RISE,LX
t
ON
f
SW
f
SYNC
SS
Spread-spectrum option only
Internally generated
1.925
1.8
+6
0.85
7
V
BIAS
= 5V
CONDITIONS
MIN
TYP
350
400
250
1.05
8
5
80
2.1
2.275
2.6
800
450
1.22
9
MAX
UNITS
mA
m
m
A
ms
ns
ns
MHz
MHz
%
Note 2:
When the typical minimum on-time of 80ns is violated, the device skips pulses.
Note 3:
Guaranteed by design; not production tested.
4
_______________________________________________________________________________________
2.1MHz, High-Voltage,
600mA Mini-Buck Converter
Typical Operating Characteristics
(V
SUP
= +14V, T
A
= +25°C, unless otherwise noted.)
MAX16904
EFFICIENCY vs. LOAD CURRENT
MAX16904 toc01
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (SKIP MODE)
MAX16904 toc02
LINE REGULATION
(I
LOAD
= 600mA)
3
OUTPUT VOLTAGE CHANGE (%)
2
1
0
-1
-2
-3
-4
6
8 10 12 14 16 18 20 22 24 26 28
INPUT VOLTAGE (V)
MAX16904 toc03
MAX16904 toc07
MAX16904 toc05
100
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
0
5V, SKIP MODE
3.3V, SKIP MODE
60
50
SUPPLY CURRENT (µA)
40
30
20
10
0
3.3V PART
4
5V, FFF MODE
5V PART
3.3V, FFF MODE
0.1
0.2
0.3
0.4
0.5
0.6
6
8 10 12 14 16 18 20 22 24 26 28
INPUT VOLTAGE (V)
LOAD CURRENT (A)
LOAD REGULATION
3
OUTPUT-VOLTAGE CHANGE (%)
2
1
0
-1
-2
-3
-4
0
0.1
0.2
0.3
0.4
0.5
0.6
LOAD CURRENT (A)
0
6
FFF MODE
MAX16904 toc04
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
15
12
SUPPLY CURRENT (µA)
9
6
3
4
SKIP MODE
8 10 12 14 16 18 20 22 24 26 28
INPUT VOLTAGE (V)
STARTUP RESPONSE
(I
LOAD
= 600mA)
MAX16904 toc06
SHUTDOWN WAVEFORM (I
LOAD
= 600mA)
EN
5V/div
I
INDUCTOR
0.5A/div
PGOOD
5V/div
V
OUT
5V/div
20µs/div
V
EN
5V/div
I
L
1A/div
V
OUT
5V/div
V
PGOOD
5V/div
1ms/div
_______________________________________________________________________________________
5