Operating Temperature Range (Note 1)........... -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
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 Information
PACKAGE TYPE: 16-PIN TQFN
Package Code
Outline Number
Land Pattern Number
Junction to Ambient (θ
JA
)
Junction to Case (θ
JC
)
T1633+5C
21-0136
90-0032
38°C/W
10°C/W
THERMAL RESISTANCE, FOUR-LAYER BOARD (Note 2):
For the latest package outline information and land patterns (footprints), go to
www.maximintegrated.com/packages.
Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
Note 1:
Junction temperature greater than +125°C degrades operating lifetimes.
Note 2:
Package thermal resistances were obtained using the MAX17631 evaluation kit with no airflow.
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Maxim Integrated
│
2
MAX17631
4.5V to 36V, 1.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics
(V
IN
= V
EN/UVLO
= 24V, R
RT
= unconnected (f
SW
= 400 kHz), C
VCC
= 2.2μF, V
MODE/SYNC
= V
EXTVCC
= V
SGND
= V
PGND
= 0V,
V
FB
= 3.67V (MAX17631A), V
FB
= 5.5V (MAX17631B), V
FB
= 1V (MAX17631C), LX = SS =
RESET
= Open, V
BST
to V
LX
= 5V,
T
A
= -40°C to 125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
INPUT SUPPLY (V
IN
)
Input-Voltage Range
Input-Shutdown Current
V
IN
I
IN-SH
I
Q_PFM
Input-Quiescent Current
I
Q_DCM
I
Q_PWM
ENABLE/UVLO (EN/UVLO)
EN/UVLO Threshold
EN Input-Leakage Current
V
CC
(LDO)
V
CC
Output-Voltage
Range
V
CC
Current Limit
V
CC
Dropout
V
CC
UVLO
EXTVCC
EXTVCC Switchover
Threshold
POWER MOSFETS
High-Side nMOS
On-Resistance
Low-Side nMOS
On-Resistance
LX Leakage Current
SOFT-START (SS)
Charging Current
I
SS
V
SS
= 0.5V
4.7
5
5.3
μA
R
DS-ONH
R
DS-ONL
I
LX_LKG
I
LX
= 0.3A, sourcing
I
LX
= 0.3A, sinking
V
LX
= (V
PGND
+1V) to (V
IN
- 1V), T
A
= +25°C
-2
137
90
275
180
+3
mΩ
mΩ
μA
V
EXTVCC
rising
V
EXTVCC
falling
4.56
4.3
4.7
4.45
4.84
4.6
V
V
CC
I
VCC-MAX
V
CC-DO
V
CC_UVR
V
CC_UVF
1mA ≤ I
VCC
≤ 15mA
6V ≤ V
IN
≤ 36V, I
VCC
= 1mA
V
CC
= 4.5V, V
IN
= 7.5V
V
IN
= 4.5V, I
VCC
= 10mA
V
CC
rising
V
CC
falling
4.05
3.65
4.2
3.8
4.75
4.75
25
5
5
50
0.3
4.3
3.9
5.25
5.25
V
mA
V
V
V
ENR
V
ENF
I
EN
V
EN/UVLO
rising
V
EN/UVLO
falling
V
EN/UVLO
= 0V, T
A
= +25°C
1.19
1.068
-50
1.215
1.09
0
1.26
1.131
+50
V
nA
V
EN/UVLO
= 0V (Shutdown mode)
MODE/SYNC = Open, V
EXTVCC
= 5V
MODE/SYNC = Open, R
RT
= 50.8kΩ,
V
EXTVCC
= 5V
DCM Mode, V
LX
= 0.1V
Normal switching mode, f
SW
= 400kHz,
V
FB
= 3V (MAX17631A), V
FB
= 4.4V
(MAX17631B), V
FB
= 0.8V (MAX17631C)
4.5
2.8
50
60
1.2
4.7
1.8
mA
μA
36
4.5
V
μA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated
│
3
MAX17631
4.5V to 36V, 1.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(V
IN
= V
EN/UVLO
= 24V, R
RT
= unconnected (f
SW
= 400 kHz), C
VCC
= 2.2μF, V
MODE/SYNC
= V
EXTVCC
= V
SGND
= V
PGND
= 0V,
V
FB
= 3.67V (MAX17631A), V
FB
= 5.5V (MAX17631B), V
FB
= 1V (MAX17631C), LX = SS =
RESET
= Open, V
BST
to V
LX
= 5V,
T
A
= -40°C to 125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
FEEDBACK (FB)
MODE/SYNC = SGND or MODE/SYNC = V
CC
,
for MAX17631A
MODE/SYNC = SGND or MODE/SYNC = V
CC
,
for MAX17631B
FB Regulation Voltage
V
FB-REG
MODE/SYNC = SGND or MODE/SYNC = V
CC
for MAX17631C
MODE/SYNC = Open, for MAX17631A
MODE/SYNC = Open, for MAX17631B
MODE/SYNC = Open for MAX17631C
For MAX17631A
FB Input-Bias Current
MODE/SYNC
V
M-DCM
MODE Threshold
SYNC Frequency-
Capture Range
SYNC Pulse Width
SYNC Threshold
CURRENT LIMIT
Peak Current-Limit
Threshold
Runaway Peak
Current-Limit Threshold
PFM Peak Current-Limit
Threshold
Valley Current-Limit
Threshold
I
PEAK-LIMIT
I
RUNAWAY-
LIMIT
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
3.26
4.94
0.889
3.26
4.94
0.89
3.3
5
0.9
3.36
5.09
0.915
21
17
3.34
5.06
0.911
3.43
5.20
0.936
μA
+50
nA
V
I
FB
For MAX17631B
0 ≤ V
FB
≤ 1V, T
A
= 25°C For MAX17631C
MODE/SYNC = V
CC
(DCM mode)
MODE/SYNC = Open (PFM mode)
MODE/SYNC = SGND (PWM mode)
f
SW
set by R
RT
1.1 x f
SW
50
-50
V
CC
- 0.65
V
M-PFM
V
M-PWM
f
SYNC
V
CC
/2
0.75
1.4 x f
SW
V
kHz
ns
V
IH
V
IL
2.1
0.8
V
2.3
2.55
MODE/SYNC = Open
MODE/SYNC = Open or MODE/SYNC = V
CC
MODE/SYNC = SGND, V
FB
> 0.65
-0.15
2.7
3.1
0.61
0
-1.8
3.1
3.5
A
A
A
I
PFM
I
VALLEY-LIMIT
+0.15
A
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Maxim Integrated
│
4
MAX17631
4.5V to 36V, 1.5A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(V
IN
= V
EN/UVLO
= 24V, R
RT
= unconnected (f
SW
= 400 kHz), C
VCC
= 2.2μF, V
MODE/SYNC
= V
EXTVCC
= V
SGND
= V
PGND
= 0V,
V
FB
= 3.67V (MAX17631A), V
FB
= 5.5V (MAX17631B), V
FB
= 1V (MAX17631C), LX = SS =
RESET
= Open, V
BST
to V
LX
= 5V,
T
A
= -40°C to 125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
RT
R
RT
= 50.8kΩ
Switching Frequency
f
SW
R
RT
= 40.2kΩ
R
RT
= 8.06kΩ
R
RT
= Open
V
FB
Undervoltage Trip
Level to Cause Hiccup
HICCUP Timeout
Minimum On-Time
Minimum Off-Time
LX Dead Time
RESET
RESET
Output-Level Low
RESET
Output-Leakage
Current
FB Threshold for
RESET
Deassertion
FB Threshold for
RESET
Assertion
RESET
Delay after FB
Reaches 95% Regulation
THERMAL SHUTDOWN (TEMP)
Thermal-Shutdown
Threshold
Thermal-Shutdown
Hysteresis
Temperature rising
165
10
°C
°C
t
ON-MIN
t
OFF-MIN
LX
DT
V
RESETL
I
RESETLKG
V
FB-OKR
V
FB-OKF
I
RESET
= 10mA
T
A
= T
J
= 25°C, V
RESET
= 5.5V
V
FB
rising
V
FB
falling
-100
93.8
90.5
95
92
1024
140
5
40
+100
97.8
94.6
For MAX17631A
V
FB-HICF
For MAX17631B
For MAX17631C
(Note 4)
380
475
1950
370
2.05
3.11
0.56
400
500
2200
400
2.13
3.22
0.58
32768
52
80
160
420
525
2450
430
2.2
3.33
0.6
Cycles
ns
ns
ns
mV
nA
%
%
Cycles
V
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 3:
Electrical specifications are production tested at T
A
= +25°C. Specifications over the entire operating temperature range are
