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MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
General Description
Benefits and Features
The MAX17630 is a high-efficiency, high-voltage,
synchronous step-down DC-DC converter with integrated
MOSFETs operating over an input-voltage range of 4.5V
to 36V. It can deliver up to 1A current. The MAX17630 is
available in three variants, MAX17630A, MAX17630B,
and MAX17630C. The MAX17630A and MAX17630B
are fixed 3.3V and fixed 5V output parts, respectively.
The MAX17630C is an adjustable output voltage (0.9V
up to 90% of VIN) part. Built-in compensation across the
output-voltage range eliminates the need for external
compensation 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 Voltage Range from
0.9V Up to 90% of VIN
• Delivers Up to 1A Over the Temperature Range
• 400kHz to 2.2MHz Adjustable Frequency with
External Clock Synchronization
• Available in a 16-Pin, 3mm x 3mm TQFN Package
●● Reduces Power Dissipation
The MAX17630 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 MAX17630 offers a low minimum ontime that allows high switching frequencies and a smaller
solution size.
• Peak Efficiency of 95%
• PFM and DCM Modes Enable Enhanced
Light-Load Efficiency
• Auxiliary Bootstrap Supply (EXTVCC) for
Improved Efficiency
• 2.8μA Shutdown Current
●● Operates Reliably in Adverse Industrial Environments
The feedback-voltage regulation accuracy over -40°C to
+125°C for the MAX17630A/MAX17630B/MAX17630C is
±1.2%.The device is available in a 16-pin (3mm x 3mm)
TQFN package. Simulation models are available.
• 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
RT
EN/UVLO
VIN
MODE/SYNC
VCC
C3
2.2µF
SGND
C2
5600pF
RESET
19-100461; Rev 0; 12/18
SS
MAX17630B
C1
2.2µF
BST
LX
C5
0.1µF
L1
15µH
C4
22µF
FB
EXTVCC
PGND
EP
VIN
6.5V TO 36V
VOUT
5V,1A
fSW : 400kHz
C1: 2.2µF/50V/X7R/1206 (C3216X7R1H225K160AE)
L1: 15µH (XAL5050-153ME)
C4: 22µF/25V/X7R/1210 (GRM32ER71E226ME15)
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Absolute Maximum Ratings
VIN to PGND..........................................................-0.3V to +40V
EN/UVLO to SGND.....................................-0.3V to (VIN + 0.3V)
LX to PGND................................................-0.3V to (VIN + 0.3V)
EXTVCC to SGND................................................-5.5V to +6.5V
BST to PGND......................................................-0.3V to +46.5V
BST to LX..............................................................-0.3V to +6.5V
BST to VCC............................................................-0.3V to +40V
RESET, SS, MODE/SYNC, VCC, RT to SGND....-0.3V to +6.5V
FB to SGND (MAX17630A & MAX17630B)............-5.5V to 6.5V
FB to SGND (MAX17630C)....................................-0.3V to 6.5V
PGND to SGND.....................................................-0.3V to +0.3V
LX Total RMS Current.........................................................±3.5A
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (Multilayer Board)
(TA = +70°C, derate 20.8mW/°C above +70°C.).....1666.7mW
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
T1633+5C
Outline Number
21-0136
Land Pattern Number
90-0032
THERMAL RESISTANCE, FOUR-LAYER BOARD (Note 2):
Junction to Ambient (θJA)
38°C/W
Junction to Case (θJC)
10°C/W
Note 1: Junction temperature greater than +125°C degrades operating lifetimes.
Note 2: Package thermal resistances were obtained using the MAX17630 evaluation kit with no airflow.
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.
www.maximintegrated.com
Maxim Integrated │ 2
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics
(VIN = VEN/UVLO = 24V, RRT = unconnected (fSW = 400 kHz), CVCC = 2.2μF, VMODE/SYNC = VEXTVCC = VSGND = VPGND = 0V,
VFB = 3.67V (MAX17630A), VFB = 5.5V (MAX17630B),VFB = 1V (MAX17630C), LX = SS = RESET = Open, VBST to VLX = 5V,
TA = -40°C to 125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
36
V
4.5
μA
INPUT SUPPLY (VIN)
Input-Voltage Range
Input-Shutdown Current
VIN
IIN-SH
VEN/UVLO = 0V (Shutdown mode)
2.8
MODE/SYNC = Open, VEXTVCC = 5V
50
MODE/SYNC = Open, RRT = 50.8kΩ,
VEXTVCC = 5V
60
IQ_DCM
DCM Mode, VLX = 0.1V
1.2
IQ_PWM
Normal Switching Mode, fSW = 400kHz,
VFB = 3V (MAX17630A), VFB = 4.4V
(MAX17630B), VFB = 0.8V (MAX17630C)
4.6
IQ_PFM
Input-Quiescent Current
4.5
μA
1.8
mA
ENABLE/UVLO (EN/UVLO)
EN/UVLO Threshold
EN Input-Leakage Current
VENR
VEN/UVLO rising
1.19
1.215
1.26
VENF
VEN/UVLO falling
1.068
1.09
1.131
VEN/UVLO = 0V, TA = +25°C
-50
0
+50
1mA ≤ IVCC ≤ 15mA
4.75
5
5.25
6V ≤ VIN ≤ 36V, IVCC = 1mA
4.75
5
5.25
25
50
IEN
V
nA
VCC (LDO)
VCC Output-Voltage
Range
VCC Current Limit
VCC Dropout
VCC UVLO
VCC
IVCC-MAX
VCC-DO
VCC = 4.5V, VIN = 7.5V
VIN = 4.5V, IVCC = 10mA
V
mA
0.3
VCC_UVR
VCC rising
4.05
4.2
4.3
VCC_UVF
VCC falling
3.65
3.8
3.9
VEXTVCC rising
4.56
4.7
4.84
VEXTVCC falling
4.3
4.45
4.6
V
V
EXTVCC
EXTVCC Switchover
Threshold
V
POWER MOSFETS
High-Side nMOS
On-Resistance
RDS-ONH
ILX = 0.3A, sourcing
150
300
mΩ
Low-Side nMOS
On-Resistance
RDS-ONL
ILX = 0.3A, sinking
100
200
mΩ
LX Leakage Current
ILX_LKG
VLX = (VPGND +1V) to (VIN - 1V), TA = +25°C
-2
+3
μA
VSS = 0.5V
4.7
5.3
μA
SOFT-START (SS)
Charging Current
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ISS
5
Maxim Integrated │ 3
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(VIN = VEN/UVLO = 24V, RRT = unconnected (fSW = 400 kHz), CVCC = 2.2μF, VMODE/SYNC = VEXTVCC = VSGND = VPGND = 0V,
VFB = 3.67V (MAX17630A), VFB = 5.5V (MAX17630B),VFB = 1V (MAX17630C), LX = SS = RESET = Open, VBST to VLX = 5V,
TA = -40°C to 125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
MODE/SYNC = SGND or MODE/SYNC = VCC,
for MAX17630A
3.26
3.3
3.34
MODE/SYNC = SGND or MODE/SYNC = VCC,
for MAX17630B
4.94
5
5.06
MODE/SYNC = SGND or MODE/SYNC = VCC
for MAX17630C
0.889
0.9
0.911
MODE/SYNC = Open, for MAX17630A
3.26
3.36
3.43
MODE/SYNC = Open, for MAX17630B
4.94
5.09
5.20
MODE/SYNC = Open for MAX17630C
0.89
0.915
0.936
UNITS
FEEDBACK (FB)
FB Regulation Voltage
FB Input-Bias Current
VFB-REG
IFB
For MAX17630A
11
For MAX17630B
17
0 ≤ VFB ≤ 1V, TA = 25ºC For MAX17630C
-50
V
μA
+50
nA
MODE/SYNC
MODE Threshold
SYNC Frequency-Capture
Range
VM-DCM
MODE/SYNC = VCC (DCM mode)
VM-PFM
MODE/SYNC = Open (PFM mode)
VM-PWM
MODE/SYNC = SGND (PWM mode)
fSYNC
fSW set by RRT
SYNC Pulse Width
SYNC Threshold
VCC - 0.65
V
VCC/2
0.75
1.1 x fSW
1.4 x fSW
50
VIH
kHz
ns
2.1
VIL
0.8
V
CURRENT LIMIT
Peak Current-Limit
Threshold
Runaway Peak
Current-Limit Threshold
PFM Peak Current-Limit
Threshold
Valley Current-Limit
Threshold
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IPEAK-LIMIT
1.6
1.86
2.14
A
IRUNAWAY-
1.89
2.32
2.6
A
LIMIT
IPFM
IVALLEYLIMIT
MODE/SYNC = Open
MODE/SYNC = Open or MODE/SYNC = VCC
MODE/SYNC = SGND, VFB > 0.65
0.41
-0.15
0
-1.8
A
+0.15
A
Maxim Integrated │ 4
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(VIN = VEN/UVLO = 24V, RRT = unconnected (fSW = 400 kHz), CVCC = 2.2μF, VMODE/SYNC = VEXTVCC = VSGND = VPGND = 0V,
VFB = 3.67V (MAX17630A), VFB = 5.5V (MAX17630B),VFB = 1V (MAX17630C), LX = SS = RESET = Open, VBST to VLX = 5V,
TA = -40°C to 125°C, unless otherwise noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
RRT = 50.8kΩ
380
400
420
RRT = 40.2kΩ
475
500
525
RRT = 8.06kΩ
1950
2200
2450
RRT = Open
370
400
430
For MAX17630A
2.05
2.13
2.2
For MAX17630B
3.11
3.22
3.33
For MAX17630C
0.56
0.58
0.6
UNITS
RT
Switching Frequency
VFB Undervoltage Trip
Level to Cause Hiccup
fSW
VFB-HICF
HICCUP Timeout
(Note 4)
Minimum On-Time
tON-MIN
Minimum Off-Time
tOFF-MIN
LX Dead Time
RESET
RESETOutput-Level Low
RESETOutput-Leakage
Current
32768
52
140
LXDT
VRESETL
IRESETLKG
TA = TJ = 25°C, VRESET = 5.5V
-100
V
Cycles
80
ns
160
ns
5
IRESET = 10mA
kHz
ns
400
mV
100
nA
FB Threshold for
RESET Deassertion
VFB-OKR
VFB rising
93.8
95
97.8
%
FB Threshold for
RESET Assertion
VFB-OKF
VFB falling
90.5
92
94.6
%
RESET Delay after FB
Reaches 95% Regulation
1024
Cycles
165
°C
10
°C
THERMAL SHUTDOWN (TEMP)
Thermal-Shutdown
Threshold
Thermal-Shutdown
Hysteresis
Temperature rising
Note 3: Electrical specifications are production tested at TA = +25ºC. Specifications over the entire operating temperature range are
guaranteed by design and characterization.
Note 4: See the Overcurrent Protection (OCP)/Hiccup Mode section for more details
www.maximintegrated.com
Maxim Integrated │ 5
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630A EFFICIENCY vs. LOAD CURRENT
FIGURE 3 CIRCUIT
toc01
90
80
80
60
50
VIN = 24V
VIN = 36V
VIN = 4.5V
30
0.6
0.8
0
1.0
VIN = 12V
30
10
0.4
VIN = 24V
40
10
0.2
VIN = 36V
50
20
0.0
80
60
20
VIN = 4.5V
0.01
100
VIN = 12V
60
50
VIN = 6.5V
40
30
0.2
0.4
0.6
0.8
LOAD CURRENT (A)
70
VIN = 36V
60
VIN = 24V
VIN = 12V
50
30
1.0
40
VIN = 4.5V
100
MAX17630B EFFICIENCY vs. LOAD CURRENT
FIGURE 4 CIRCUIT toc06
VIN = 6.5V
0.01
70
60
V = 24V
VIN = 12V IN
50
VIN = 36V
VIN = 6.5V
40
30
0.1
LOAD CURRENT (A)
20
0.001
1
0.01
0.1
LOAD CURRENT (A)
1
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, fSW = 400kHz
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, fSW = 400kHz
CONDITIONS: FIXED 5V OUTPUT, PFM MODE, fSW = 400kHz
MAX17630C EFFICIENCY vs. LOAD CURRENT
FIGURE 7 CIRCUIT
toc07
MAX17630C EFFICIENCY vs. LOAD CURRENT
FIGURE 7 CIRCUIT
toc08
MAX17630C EFFICIENCY vs. LOAD CURRENT
FIGURE 7 CIRCUIT
toc09
100
100
100
90
VIN = 24V
50
VIN = 8V
40
80
90
85
VIN = 16V
VIN = 12V
80
30
20
75
10
0.0
0.2
0.4
0.6
0.8
1.0
LOAD CURRENT (A)
CONDITIONS: ADJUSTABLE 5V OUTPUT,
PWM MODE, fSW = 1.5MHz
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70
0.005
VIN = 24V
VIN = 8V
EFFICIENCY (%)
VIN = 12V
60
VIN = 16V
EFFICIENCY (%)
70
0
90
95
80
EFFICIENCY (%)
VIN = 12V
50
80
40
0.0
VIN = 36V
90
20
10
VIN = 24V
0.01
0.1
1
LOAD CURRENT (A)
CONDITIONS: FIXED 3.3V OUTPUT, PFM MODE, fSW = 400kHz
80
EFFICIENCY (%)
70
VIN = 36V
VIN = 24V
60
20
0.001
90
80
EFFICIENCY (%)
1
MAX17630B EFFICIENCY vs. LOAD CURRENT
FIGURE 4 CIRCUIT toc05
100
90
0
0.1
LOAD CURRENT (A)
CONDITIONS: FIXED 3.3V OUTPUT, DCM MODE, fSW = 400kHz
MAX17630B EFFICIENCY vs. LOAD CURRENT
FIGURE 4 CIRCUIT
toc04
70
30
LOAD CURRENT (A)
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE, fSW = 400kHz
MAX17630A EFFICIENCY vs. LOAD CURRENT
FIGURE 3 CIRCUIT
toc03
90
70
40
0
100
EFFICIENCY (%)
VIN = 12V
EFFICIENCY (%)
70
EFFICIENCY (%)
100
90
MAX17630A EFFICIENCY vs. LOAD CURRENT
FIGURE 3 CIRCUIT
toc02
EFFICIENCY (%)
100
70
VIN = 16V
50
VIN = 12V
40
VIN = 8V
30
20
0.05
0.5
LOAD CURRENT (A)
CONDITIONS: ADJUSTABLE 5V OUTPUT,
PFM MODE, fSW = 1.5MHz
VIN = 24V
60
0.01
0.1
1
LOAD CURRENT (A)
CONDITIONS: ADJUSTABLE 5V OUTPUT,
DCM MODE, fSW = 1.5MHz
Maxim Integrated │ 6
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630A EFFICIENCY vs. LOAD CURRENT
WITH XAL4040 INDUCTOR, FIGURE 3 CIRCUIT
100
90
90
80
80
80
70
70
VIN = 12V
60
50
VIN = 24V
VIN = 36V
VIN = 4.5V
40
60
10
10
0.4
0.6
0.8
LOAD CURRENT (A)
0.2
VIN = 36V
3.31
3.31
3.30
VIN = 4.5V
3.32
OUTPUT VOLTAGE (V)
VIN = 12V
VIN = 24V
3.30
0.5
LOAD CURRENT (A)
CONDITIONS: FIXED 3.3V OUTPUT,
PWM MODE, fSW = 400kHz
0.01
0.1
LOAD CURRENT (A)
1
3.31
3.30
VIN = 36V
VIN = 24V
OUTPUT VOLTAGE (V)
1
MAX17630A LOAD AND LINE REGULATION
FIGURE 3 CIRCUIT toc15
VIN = 4.5V
VIN = 12V
3.36
VIN = 24V
3.34
VIN = 36V
3.32
3.28
3.26
0.0
0.5
LOAD CURRENT (A)
1.0
VIN = 36V
VIN = 24V
5.08
0.0
0.5
1.0
LOAD CURRENT (A)
CONDITIONS: FIXED 3.3V OUTPUT, PFM MODE, fSW = 400kHz
CONDITIONS: FIXED 3.3V OUTPUT, DCM MODE, fSW = 400kHz
0.5
1.0
LOAD CURRENT (A)
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, fSW = 400kHz
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0.1
LOAD CURRENT (A)
3.30
MAX17630B LOAD AND LINE REGULATION
FIGURE 4 CIRCUIT
toc17
5.08
VIN = 36V
VIN = 12V
5.07
5.07
5.06
VIN = 6.5V
5.06
0.0
0.01
3.38
3.31
5.05
5.04
VIN = 4.5V
3.40
VIN = 12V
VIN = 4.5V
5.06
VIN = 6.5V
VIN = 12V
CONDITIONS: FIXED 3.3V OUTPUT,
DCM MODE, fSW = 400kHz
MAX17630A LOAD AND LINE REGULATION
FIGURE 3 CIRCUIT
toc14
3.32
3.29
1.0
VIN = 12V
5.07
VIN = 24V
30
0
MAX17630B LOAD AND LINE REGULATION
FIGURE 4 CIRCUIT
toc16
5.08
40
10
3.30
0.0
VIN = 36V
50
20
OUTPUT VOLTAGE (V)
3.29
60
CONDITIONS: FIXED 3.3V OUTPUT, PFM MODE, fSW = 400kHz
MAX17630A LOAD AND LINE REGULATION
FIGURE 3 CIRCUIT toc13
3.32
VIN = 4.5V
0
0.001
1.0
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE, fSW = 400kHz
3.32
VIN = 12V
30
20
0.0
VIN = 24V
40
20
0
VIN = 36V
50
OUTPUT VOLTAGE (V)
70
EFFICIENCY (%)
90
30
OUTPUT VOLTAGE (V)
MAX17630A EFFICIENCY vs. LOAD CURRENT
WITH XAL4040 INDUCTOR, FIGURE 3 CIRCUIT
toc12
toc11
100
EFFICIENCY (%)
EFFICIENCY (%)
100
MAX17630A EFFICIENCY vs. LOAD CURRENT
WITH XAL4040 INDUCTOR, FIGURE 3 CIRCUIT
toc10
5.05
0.0
VIN = 24V
0.5
LOAD CURRENT (A)
1.0
CONDITIONS: FIXED 5V OUTPUT, DCM MODE, fSW = 400kHz
Maxim Integrated │ 7
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630B LOAD AND LINE REGULATION
FIGURE 4 CIRCUIT toc18
VIN = 6.5V
VIN = 24V
5.15
MAX17630C LOAD AND LINE REGULATION
FIGURE 7 CIRCUIT
toc20
5.02
5.01
VIN = 12V
5.20
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
5.25
VIN = 36V
5.10
5.05
4.98
4.95
4.96
0.5
1.0
LOAD CURRENT (A)
CONDITIONS: FIXED 5V OUTPUT, PFM MODE, fSW = 400kHz
MAX17630C LOAD AND LINE REGULATION
toc21
FIGURE 7 CIRCUIT
VIN = 16V
4.99
4.97
0.0
VIN = 12V
5.00
5.00
4.90
MAX17630C LOAD AND LINE REGULATION
FIGURE 7 CIRCUIT
toc19
5.02
OUTPUT VOLTAGE (V)
5.30
4.95
VIN = 8V
5.00
VIN = 8V
VIN = 12V
VIN = 16V VIN = 24V
4.98
4.96
VIN = 24V
4.94
0.0
0.5
1.0
LOAD CURRENT (A)
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE, fSW = 1.5MHz
0.0
0.5
LOAD CURRENT (A)
1.0
CONDITIONS: ADJUSTABLE 5V OUTPUT, DCM MODE, fSW = 1.5MHz
MAX17630A SOFT-START
WITH PREBIAS VOLTAGE OF 1.65V
FIGURE 3 CIRCUIT
toc23
MAX17630A SOFT-START/SHUTDOWN FROM EN/UVLO
FIGURE 3 CIRCUIT
toc22
5.09
VIN = 16V
OUTPUT VOLTAGE (V)
5.07
VEN/UVLO
5V/div
1A/div
VOUT
VRESET
1V/div
5V/div
5V/div
ILX
1A/div
VEN/UVLO
5V/div
VOUT
2V/div
ILX
VRESET
5.05
5.03
VIN = 24V
VIN = 8V
5.01
4.99
VIN = 36V
4.97
4.95
0.0
0.5
LOAD CURRENT (A)
1ms/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
1.0
CONDITIONS: ADJUSTABLE 5V OUTPUT, PFM MODE, fSW = 1.5MHz
MAX17630B SOFT-START
WITH PREBIAS VOLTAGE OF 2.5V
FIGURE 4 CIRCUIT
toc25
MAX17630B SOFT-START/SHUTDOWN FROM EN/UVLO
FIGURE 4 CIRCUIT
toc24
VEN/UVLO
VOUT
ILX
5V/div
VEN/UVLO
5V/div
2V/div
VOUT
2V/div
1A/div
VRESET
5V/div
VRESET
5V/div
1ms/div
CONDITIONS: FIXED 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
www.maximintegrated.com
1ms/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
ILX
1A/div
1ms/div
CONDITIONS: FIXED 5V OUTPUT, PWM MODE,
20mA LOAD, fSW = 400kHz
Maxim Integrated │ 8
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630C SOFT-START
WITH PREBIAS VOLTAGE OF 2.5V
FIGURE 7 CIRCUIT
toc27
MAX17630C SOFT-START/SHUTDOWN FROM EN/UVLO
FIGURE 7 CIRCUIT
toc26
VEN/UVLO
5V/div
VEN/UVLO
MAX17630A STEADY-STATE PERFORMANCE
FIGURE 3 CIRCUIT
toc28
5V/div
10V/div
VLX
VOUT(AC)
VOUT
2V/div
VOUT
ILX
1A/div
VRESET
5V/div
VRESET
5V/div
ILX
1A/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 1.5MHz
VLX
10V/div
VOUT(AC)
1A/div
2µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
toc31
toc30
10V/div
VOUT(AC)
ILX
MAX17630B STEADY-STATE PERFORMANCE
FIGURE 4 CIRCUIT
MAX17630A STEADY-STATE PERFORMANCE
FIGURE 3 CIRCUIT
MAX17630A STEADY-STATE PERFORMANCE
FIGURE 3 CIRCUIT
toc29
VLX
2V/div
1ms/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
20mA LOAD, fSW = 1.5MHz
1ms/div
20mV/div
50mV/div
VLX
10V/div
VOUT(AC)
20mV/div
20mV/div
ILX
0.2A/div
ILX
0.5A/div
MAX17630B STEADY-STATE PERFORMANCE
FIGURE 4 CIRCUIT
toc32
VLX
10V/div
MAX17630B STEADY-STATE PERFORMANCE
FIGURE 4 CIRCUIT
toc33
VLX
VOUT(AC)
VOUT(AC)
1A/div
2µs/div
CONDITIONS: FIXED 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
20µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PFM MODE,
20mA LOAD, fSW = 400kHz
1µs/div
CONDITIONS: FIXED 3.3V OUTPUT, DCM MODE,
20mA LOAD, fSW = 400kHz
ILX
10V/div
50mV/div
20mV/div
ILX
0.2A/div
1µs/div
CONDITIONS: FIXED 5V OUTPUT, DCM MODE,
20mA LOAD, fSW = 400kHz
www.maximintegrated.com
ILX
0.5A/div
20µs/div
CONDITIONS: FIXED 5V OUTPUT, PFM MODE,
20mA LOAD, fSW = 400kHz
Maxim Integrated │ 9
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630C STEADY-STATE PERFORMANCE
FIGURE 7 CIRCUIT
toc34
MAX17630C STEADY-STATE PERFORMANCE
FIGURE 7 CIRCUIT
toc35
VOUT(AC)
VLX
20mV/div
MAX17630C STEADY-STATE PERFORMANCE
FIGURE 4 CIRCUIT
toc36
VOUT(AC)
100mV/div
10V/div
VOUT(AC)
20mV/div
ILX
1A/div
1µs/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 1.5MHz
toc37
100mV/div
IOUT
10V/div
ILX
0.5A/div
400ns/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, DCM MODE,
20mA LOAD, fSW = 1.5MHz
MAX17630A LOAD TRANSIENT BETWEEN 0A AND 0.5A
FIGURE 3 CIRCUIT
VOUT(AC)
VLX
MAX17630A LOAD TRANSIENT BETWEEN 0.5A AND 1A
FIGURE 3 CIRCUIT
toc38
VOUT(AC)
100mV/div
VLX
10V/div
ILX
0.5A/div
10µs/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PFM MODE,
20mA LOAD, fSW = 1.5MHz
MAX17630A LOAD TRANSIENT BETWEEN 20mA AND 0.5A
FIGURE 3 CIRCUIT
toc39
VOUT(AC)
100mV/div
0.5A/div
IOUT
0.5A/div
0.5A/div
IOUT
100µs/div
100µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE, fSW = 400kHz
MAX17630A LOAD TRANSIENT BETWEEN 20mA AND 0.5A
FIGURE 3 CIRCUIT
toc40
VOUT(AC)
200µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE, fSW = 400kHz
CONDITIONS: FIXED 3.3V OUTPUT, DCM MODE, fSW = 400kHz
MAX17630B LOAD TRANSIENT BETWEEN 0A AND 0.5A
FIGURE 4 CIRCUIT
toc41
100mV/div
VOUT(AC)
IOUT
0.5A/div
400µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PFM MODE, fSW = 400kHz
www.maximintegrated.com
50mV/div
IOUT
0.5A/div
100µs/div
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, fSW = 400kHz
Maxim Integrated │ 10
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630B LOAD TRANSIENT BETWEEN 0.5A AND 1A MAX17630B LOAD TRANSIENT BETWEEN 20mA AND 0.5A
MAX17630B LOAD TRANSIENT BETWEEN 20mA AND 0.5A
FIGURE 4 CIRCUIT
FIGURE 4 CIRCUIT
FIGURE 4 CIRCUIT
toc42
toc43
toc44
VOUT(AC)
100mV/div
0.5A/div
IOUT
VOUT(AC)
100mV/div
IOUT
0.5A/div
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, fSW = 400kHz
MAX17630C LOAD TRANSIENT BETWEEN 0A AND 0.5A
FIGURE 7 CIRCUIT
CONDITIONS: FIXED 5V OUTPUT, DCM MODE, fSW = 400kHz
IOUT
0.2A/div
toc47
VOUT(AC)
50mV/div
IOUT
0.5A/div
100mV/div
IOUT
40µs/div
100mV/div
VSYNC
VOUT(AC)
VLX
IOUT
VOUT(AC)
0.2A/div
100µs/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE, fSW = 1.5MHz CONDITIONS: ADJUSTABLE 5V OUTPUT, DCM MODE, f = 1.5MHz
SW
MAX17630C LOAD TRANSIENT BETWEEN 20mA AND 0.5A MAX17630A EXTERNAL CLOCK SYNCHRONIZATION
FIGURE 7 CIRCUIT
FIGURE 3 CIRCUIT
toc48
toc49
VOUT(AC)
200µs/div
CONDITIONS: FIXED 5V OUTPUT, PFM MODE, fSW = 400kHz
toc46
40µs/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE, fSW = 1.5MHz
0.5A/div
MAX17630C LOAD TRANSIENT BETWEEN 0.5A AND 1A MAX17630C LOAD TRANSIENT BETWEEN 20mA AND 0.5A
FIGURE 7 CIRCUIT
FIGURE 7 CIRCUIT
toc45
50mV/div
100mV/div
IOUT
100µs/div
100µs/div
VOUT(AC)
VOUT(AC)
5V/div
50mV/div
10V/div
MAX17630B EXTERNAL CLOCK SYNCHRONIZATION
FIGURE 4 CIRCUIT
toc50
VSYNC
VOUT(AC)
VLX
5V/div
50mV/div
10V/div
0.5A/div
1A/div
IOUT
1A/div
4µs/div
4µs/div
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE, 1A LOAD CURRENT CONDITIONS: FIXED 5V OUTPUT, PWM MODE, 1A LOAD CURRENT
CONDITIONS: ADJUSTABLE 5V OUTPUT, PFM MODE, fSW = 1.5MHz
fSW = 400kHz, EXTERNAL CLOCK FREQUENCY = 440kHz
fSW = 400kHz, EXTERNAL CLOCK FREQUENCY = 440kHz
IOUT
400µs/div
www.maximintegrated.com
Maxim Integrated │ 11
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics (continued)
(VEN/UVLO = VIN = 24V, VSGND = VPGND = 0V, CVCC = 2.2μF, CBST = 0.1μF, CSS = 5600pF, TA = -40°C to +125°C, unless otherwise
noted. Typical values are at TA = +25°C. All voltages are referenced to SGND, unless otherwise noted.)
MAX17630A CLOSED-LOOP BODE PLOT
FIGURE 3 CIRCUIT
toc53
50
PHASE
40
VSYNC
5V/div
VOUT(AC)
VOUT
2V/div
GAIN (dB)
50mV/div
10V/div
IOUT
MAX17630B CLOSED-LOOP BODE PLOT
FIGURE 4 CIRCUIT
toc54
40
10
20
0
0
GAIN
-10
-20
-40
GAIN CROSSOVER
FREQUENCY = 45kHz
PHASE MARGIN = 66.5°
-40
-50
100µs/div
1k
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE, fSW = 1.5MHz
MAX17630C CLOSED-LOOP BODE PLOT
FIGURE 5 CIRCUIT
toc55
-60
-80
10k
100k
FREQUENCY (Hz)
CONDITIONS: FIXED 3.3V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
MAX17630C CLOSED-LOOP BODE PLOT
FIGURE 6 CIRCUIT
toc56
-100
80
40
30
60
30
60
40
20
40
20
40
10
20
10
20
10
20
0
0
0
0
0
0
40
30
60
20
-20
GAIN CROSSOVER
FREQUENCY = 49.2kHz
PHASE MARGIN = 67.6°
-30
-40
-50
1k
10k
FREQUENCY (Hz)
100k
-10
-40
-20
-60
-30
-80
-40
-100
-50
-20
GAIN
GAIN CROSSOVER FREQUENCY = 50.6kHz
PHASE MARGIN = 67°
1k
CONDITIONS: FIXED 5V OUTPUT, PWM MODE, 1A LOAD, fSW = 400kHz
MAX17630C CLOSED-LOOP BODE PLOT
FIGURE 7 CIRCUIT
PHASE
100
80
30
60
20
40
10
20
0
0
-10
GAIN
-20
GAIN CROSSOVER FREQUENCY = 87.3kHz
PHASE MARGIN = 66.6°
-30
-40
-50
-20
-40
-60
-80
10k
100k
FREQUENCY (Hz)
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 1.5MHz
www.maximintegrated.com
-100
-20
-60
-30
-80
-40
-100
-50
40
30
PEAK EMISSIONS
20
AVERAGE EMISSIONS
0.15
1
-20
GAIN
-40
GAIN CROSSOVER FREQUENCY = 52.7kHz
PHASE MARGIN = 67°
1k
10k
FREQUENCY (Hz)
100k
-60
-80
-100
TUV Rheinland
Final_ScanV
MaximIC_MAX17630
Final_ScanH
MAX17630B,
5V
OUTPUT,
1A
LOAD
CURRENT
RE 30MHz-1GHz
Limit
RADIATED EMI CURVE
toc59
70.0
70
50.0
50
40.0
40
30.0
30
20.0
20
CISPR-22 CLASS B QP LIMIT
VERTICAL SCAN
10.0
10
00
10
0
80
60.0
60
CISPR-22 CLASS B AVG LIMIT
50
100
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
CISPR-22 CLASS B QP LIMIT
60
AMPLITUDE (dBµV)
40
-40
MAX17630B, 5V OUTPUT, 1A LOAD CURRENT
CONDUCTED EMI CURVE
toc58
PHASE (°)
toc57
50
10k
100k
FREQUENCY (Hz)
CONDITIONS: ADJUSTABLE 3.3V OUTPUT, PWM MODE,
1A LOAD, fSW = 400kHz
PHASE
-10
AMPLITUDE(dBµV)
-20
GAIN
PHASE
Am p litu d e (d Bu V /m )
-10
GAIN (dB)
80
PHASE
40
PHASE (°)
50
GAIN (dB)
50
100
PHASE (°)
100
50
GAIN (dB)
1A/div
1A/div
2µs/div
CONDITIONS: ADJUSTABLE 5V OUTPUT, PWM MODE,
1A LOAD CURRENT, fSW = 1.5MHz,
EXTERNAL CLOCK FREQUENCY = 1.65MHz
GAIN (dB)
60
20
-30
IOUT
80
30
-20
VLX
100
PHASE (°)
toc52
PHASE (°)
MAX17630C
OVERLOAD PROTECTION FIGURE 7 CIRCUIT
MAX17630C EXTERNAL CLOCK SYNCHRONIZATION
FIGURE 7 CIRCUIT
toc51
10
30
FREQUENCY (MHz)
MEASURED ON THE MAX17630BEVKIT WITH L2 = 10µH,
C13 = C14 = 4.7µF/50V/X7R/1206
-10.0
-10
30.0M
30
HORIZONTAL SCAN
100.0M
100
1.0G
1000
Frequency (Hz)(MHz)
FREQUENCY
RE 30MHz-1GHz_0-360deg_90deg
step_1-4mtr Height_Quick
CONDITION: MEASURED
ON THE Scan_Test2.TIL
MAX17630EVKITB
01:04:51 PM, Wednesday, November 28, 2018
Maxim Integrated │ 12
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
LX
LX
BST
EXTVCC
Pin Configuration
12
11
10
9
TOP VIEW
14
VIN
15
VIN
16
MAX17630A
MAX17630B
MAX17630C
*EP
+
EN/UVLO
1
2
3
4
MODE/
SYNC
PGND
SGND
13
VCC
PGND
8
RESET
7
RT
6
FB
5
SS
16-PIN TQFN
(3mm x 3mm)
Pin Description
PIN
NAME
1
EN/UVLO
2
VCC
3
SGND
4
MODE/SYNC
5
SS
www.maximintegrated.com
FUNCTION
Enable/Undervoltage Lockout Pin. Drive EN/UVLO high to enable the output. Connect to the
center of the resistor-divider between VIN and SGND to set the input voltage at which the part
turns on. Connect to VIN pins for always on operation. Pull low (lower than VENF) for
disabling the device.
5V LDO Output. Bypass VCC with a 2.2μF ceramic capacitance to SGND.
LDO doesn't support the external loading on VCC.
Analog Ground
MODE/SYNC Pin Configures the Device to Operate either in PWM, PFM, or DCM Modes of
Operation. Leave MODE/SYNC open for PFM operation (pulse skipping at light loads). Connect
MODE/SYNC to SGND for constant-frequency PWM operation at all loads.
Connect MODE/SYNC to VCC for DCM operation at light loads.The device can be
synchronized to an external clock using this pin. See the Mode Selection and External Clock
Synchronization (MODE/SYNC) section for more details.
Soft-Start Input. Connect a capacitor from SS to SGND to set the soft-start time.
Maxim Integrated │ 13
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Pin Description (continued)
PIN
NAME
FUNCTION
6
FB
Feedback Input. Connect the output voltage node (VOUT) to FB for MAX17630A and MAX17630B.
Connect FB to the center node of an external resistor-divider from the output to SGND to set the
output voltage for MAX17630C. See the Adjusting Output Voltage section for more details.
7
RT
Programmable Switching Frequency Input. Connect a resistor from RT to SGND to set the
regulator’s switching frequency between 400kHz and 2.2MHz. Leave RT open for the default
400kHz frequency. See the Setting the Switching Frequency (RT) section for more details.
8
RESET
Open-Drain RESET Output. The RESET output is driven low if FB drops below 92% of its set
value. RESET goes high 1024 cycles after FB rises above 95% of its set value.
9
EXTVCC
External Power Supply Input Reduces the Internal-LDO Loss. Connect it to buck output when
it is programmed to 5V only. When EXTVCC is not used, connect it to SGND.
10
BST
11, 12
LX
13, 14
PGND
15, 16
VIN
Power-Supply Input Pins. 4.5V to 36V input-supply range. Decouple to PGND with a 2.2μF
capacitor; place the capacitor close to the VIN and PGND pins.
—
EP
Exposed Pad. Always connect EP to the SGND pin of the IC. Also, connect EP to a large SGND
plane with several thermal vias for best thermal performance. Refer to the MAX17630 EV kit data
sheet for an example of the correct method for EP connection and thermal vias.
www.maximintegrated.com
Boost Flying Capacitor. Connect a 0.1μF ceramic capacitor between BST and LX.
Switching Node Pins. Connect LX pins to the switching side of the inductor.
Power Ground Pins of the Converter. Connect externally to the power ground plane.
Refer to the MAX17630 EV kit data sheet for a layout example.
Maxim Integrated │ 14
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Functional Block Diagram
MAX17630A/MAX17630B/MAX17630C
EXTVCC
5V
VCC
BST
LDO
VIN
SGND
CURRENT- SENSE
LOGIC
EN/UVLO
1.215V
RT
ENOK
PWM/PFM/
HICCUP
LOGIC
LX
HICCUP
OSCILLATOR
SYNC
PGND
*S1
RT
FB
*S2
*S3
RB
THERMAL
SHUTDOWN
ERROR AMPLIFIER/
LOOP COMPENSATION
MODE
SELECTION
LOGIC
SWITCHOVER LOGIC
VCC
SS
SLOPE
COMPENSATION
MODE/SYNC
SYNC
ENOK
RESET
5µA
HICCUP
FB
RESET
LOGIC
*S1: CLOSE, *S2,*S3 : OPEN FOR MAX17630C
*S1: OPEN, *S2,*S3: CLOSE FOR MAX17630A/MAX17630B
RT: 242kΩ, RB: 54kΩ FOR MAX17630B
RT: 229kΩ, RB: 86kΩ FOR MAX17630A
www.maximintegrated.com
Maxim Integrated │ 15
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Detailed Description
The MAX17630 is a high-efficiency, high-voltage,
synchronous step-down DC-DC converter with integrated
MOSFETs operating over an input-voltage range of 4.5V
to 36V. It can deliver up to 1A current. MAX17630A and
MAX17630B are fixed 3.3V and fixed 5V output parts,
respectively. MAX17630C is the adjustable output voltage
(0.9V up to 90% of VIN) part. Built-in compensation
across the output-voltage range eliminates the need
for external compensation components. The feedbackvoltage regulation accuracy over -40°C to +125°C is
±1.2% for MAX17630A/MAX17630B/MAX17630C.
The device features a peak-current-mode control
architecture. An internal transconductance error amplifier
produces an integrated error voltage at an internal node,
which sets the duty cycle using a PWM comparator, a highside current-sense amplifier, and a slope-compensation
generator. At each rising edge of the clock, the highside MOSFET turns on and remains on until either
the appropriate or maximum duty cycle is reached, or
the peak current limit is detected. During the high-side
MOSFET’s on-time, the inductor current ramps up. During
the second half of the switching cycle, the high-side
MOSFET turns off and the low-side MOSFET turns on.
The inductor releases the stored energy as its current
ramps down and provides current to the output.
The device features a MODE/SYNC pin that can be used
to operate the device in PWM, PFM, or DCM control
modes. The device also features adjustable-input undervoltage lockout, adjustable soft-start, open-drain RESET,
and external frequency synchronization features. The
MAX17630 offers a low minimum on-time that enables
to design converter at high switching frequencies and a
small solution size.
Mode Selection and External Clock
Synchronization (MODE/SYNC)
The MAX17630 supports PWM, PFM, and DCM mode
of operation. The device enters the required mode of
operation based on the setting of the MODE/SYNC pin
as detected within 1.5ms after VCC and EN/UVLO voltages exceed their respective UVLO rising thresholds
(VCC_UVR, VENR). If the MODE/SYNC pin is open, the
device operates in PFM mode at light loads. If the state
of the MODE/SYNC pin is low (< VM-PWM), the device
operates in constant-frequency PWM mode at all loads. If
the state of the MODE/ SYNC pin is high (> VM-DCM), the
device operates in DCM mode at light loads.
During external clock synchronization, the device operates
in PWM mode irrespective of mode of operation detected.
www.maximintegrated.com
When 16 external clock rising edges are detected on the
MODE/SYNC pin, the internal oscillator frequency set by
the RT pin (fSW) changes to external clock frequency, and
the device transitions to PWM mode. The device remains
in PWM mode until EN/UVLO or input power is cycled.
The external clock frequency must be between 1.1 x fSW
and 1.4 × fSW. The minimum external clock pulse width
should be greater than 50ns. The off-time duration of the
external clock should be at least 160ns. See the MODE/
SYNC section in the Electrical Characteristics table for
details.
PWM Mode Operation
In PWM mode, the inductor current is allowed to go
negative. PWM operation provides constant frequency
operation at all loads, and is useful in applications
sensitive to switching frequency. However, the PWM
mode of operation gives lower efficiency at light loads
compared to PFM and DCM modes of operation.
PFM Mode Operation
PFM mode of operation disables negative inductor
current and additionally skips pulses at light loads for high
efficiency. In PFM mode, the inductor current is forced to
a fixed peak of IPFM (410mA (typ)) every clock cycle until
the output rises to 102.3% of the set nominal output voltage. Once the output reaches 102.3% of the set nominal
output voltage, both the high-side and low-side FETs
are turned off and the device enters hibernate operation
until the load discharges the output to 101.1% of the set
nominal output voltage. Most of the internal blocks
are turned off in hibernate operation to save quiescent
current. After the output falls below 101.1% of the set
nominal output voltage, the device comes out of hibernate
operation, turns on all internal blocks, and again commences
the process of delivering pulses of energy to the output
until it reaches 102.3% of the set nominal output voltage.
The advantage of the PFM mode is higher efficiency at
light loads because of lower quiescent current drawn from
supply. The disadvantage is that the output-voltage ripple is
higher compared to PWM or DCM modes of operation and
switching frequency is not constant at light loads.
DCM Mode Operation
DCM mode of operation features constant frequency
operation down to lighter loads than PFM mode, not
by skipping pulses, but by disabling negative inductor
current at light loads. DCM operation offers efficiency
performance that lies between PWM and PFM modes.
The output-voltage ripple in DCM mode is comparable to
PWM mode and relatively lower compared to PFM mode.
Maxim Integrated │ 16
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Linear Regulator (VCC and EXTVCC)
The MAX17630 has an internal low dropout (LDO)
regulator that powers VCC from VIN. This LDO is enabled
during power-up or when EN/UVLO is recycled. When
VCC is above its UVLO, if EXTVCC is greater than 4.7V
(typ), internal VCC is powered by EXTVCC and LDO is
disabled from VIN. Powering VCC from EXTVCC increases
efficiency at higher input voltages. The typical VCC output
voltage is 5V. Bypass VCC to SGND with a 2.2μF lowESR ceramic capacitor. VCC powers the internal blocks
and the low-side MOSFET driver and recharges the
external bootstrap capacitor.
The MAX17630 employs an undervoltage-lockout
circuit that forces the buck converter off when VCC falls
below VCC_UVF. The buck converter can be immediately
enabled again when VCC > VCC_UVR. The 400mV UVLO
hysteresis prevents chattering on power-up/power-down.
In applications where the buck-converter output is
connected to the EXTVCC pin, if the output is shorted to
ground, then the transfer from EXTVCC to internal LDO
happens seamlessly without any impact to the normal
functionality. Connect the EXTVCC pin to SGND, when
not in use.
Setting the Switching Frequency (RT)
The switching frequency of the device can be programmed
from 400kHz to 2.2MHz by using a resistor connected
from the RT pin to SGND. The switching frequency (fSW)
is related to the resistor connected at the RT pin (RRT) by
the following equation:
21000
RRT = f
− 1.7
SW
Where RRT is in kΩ and fSW is in kHz. Leaving the RT pin
open makes the device operate at the default switching
frequency of 400kHz. See Table 1 for RT resistor values
for a few common switching frequencies.
Table 1. Switching Frequency vs. RT
Resistor
SWITCHING FREQUENCY (kHz)
RT RESISTOR (kΩ)
400
Open
400
50.8
500
40.2
2200
8.06
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Operating Input-Voltage Range
The minimum and maximum operating input voltages for
a given output voltage setting should be calculated as
follows:
VOUT
VIN(MAX) = f
SW(MAX) × tON-MIN(MAX)
where:
VOUT = Steady-state output voltage
IOUT(MAX) = Maximum load current
RDCR(MAX) = Worst-case DC resistance of the inductor
fSW(MAX) = Maximum switching frequency
tOFF-MIN(MAX) = Worst-case minimum switch off-time
(160ns)
tON-MIN(MAX) = Worst-case minimum switch on-time
(80ns)
RDS-ONL(MAX) and RDS-ONH(MAX) = Worst-case
on-state resistances of low-side and high-side internal
MOSFETs, respectively.
Overcurrent Protection (OCP)/Hiccup Mode
The device is provided with a robust overcurrentprotection (OCP) scheme that protects the device under
overload and output short-circuit conditions. A cycle-bycycle peak current limit turns off the high-side MOSFET
whenever the high-side switch current exceeds an internal
limit of IPEAK-LIMIT (1.86A (typ)). A runaway peak current
limit on the high-side switch current at IRUNAWAY-LIMIT
(2.32A (typ)) protects the device under high input voltage
short-circuit conditions when there is insufficient output
voltage available to restore the inductor current that
built up during the on period of the step-down converter.
One occurrence of the runaway current limit triggers a
hiccup mode. In addition, if feedback voltage drops to
VFB-HICF due to a fault condition any time after soft-start
is complete, hiccup mode is triggered. In hiccup mode,
the converter is protected by suspending switching for a
hiccup timeout period of 32,768 clock cycles of half the
programmed switching frequency. Once the hiccup timeout period expires, soft-start is attempted again. Note that
when soft-start is attempted under overload condition, if
feedback voltage does not exceed VFB-HICF, the device
continues to switch at half the programmed switching
frequency for the time duration of the programmed
soft-start time and 1024 clock cycles. Hiccup mode of
operation ensures low power dissipation under output
short-circuit conditions.
Maxim Integrated │ 17
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
RESET Output
The device includes a RESET comparator to monitor
the status of the output voltage. The open-drain RESET
output requires an external pullup resistor. RESET goes
high (high impedance) 1024 switching cycles after the
regulator output increases above 95% of the designed
nominal regulated voltage. RESET goes low when the
regulator output voltage drops to below 92% of the set
nominal output voltage. RESET also goes low during
thermal shutdown or when the EN/UVLO pin goes below
VENF.
Prebiased Output
When the device starts into a prebiased output, both the
high-side and the low-side switches are turned off so that
the converter does not sink current from the output. Highside and low-side switches do not start switching until
the PWM comparator commands the first PWM pulse, at
which point switching commences. The output voltage is
then smoothly ramped up to the target value in alignment
with the internal reference.
Thermal-Shutdown Protection
Thermal-shutdown protection limits junction temperature
of the device. When the junction temperature of the
device exceeds +165ºC, an on-chip thermal sensor
shuts down the device, allowing the device to cool. The
thermal sensor turns the device on again after the junction
temperature cools by 10ºC. Soft-start gets de-asserted
during thermal shutdown and it initiates the start-up
operation when the device recovers from thermal
shutdown. Carefully evaluate the total power dissipation
(see the Power Dissipation section) to avoid unwanted
triggering of the thermal shutdown during normal
operation.
Applications Information
Input Capacitor Selection
The input filter capacitor reduces peak currents drawn
from the power source and reduces noise and voltage
ripple on the input caused by the circuit’s switching.
The input capacitor RMS current requirement (IRMS) is
defined by the following equation:
IRMS = IOUT(MAX) ×
√VOUT ×
( VIN - VOUT )
VIN
where, IOUT(MAX) is the maximum load current. IRMS has
a maximum value when the input voltage equals twice the
output voltage (VIN = 2 x VOUT), so
IRMS(MAX) =
IOUT(MAX)
2
.
Choose an input capacitor that exhibits less than +10°C
temperature rise at the RMS input current for optimal
long-term reliability. Use low-ESR ceramic capacitors with
high-ripple-current capability at the input. X7R capacitors
are recommended in industrial applications for their
temperature stability. Calculate the input capacitance
using the following equation:
CIN
=
(
IOUT MAX × D × 1 − D
(
)
η × fSW × ∆ VIN
)
where:
D = VOUT/VIN is the duty ratio of the converter
fSW = Switching frequency
ΔVIN = Allowable input-voltage ripple
η = Efficiency
In applications where the source is located distant from
the device input, an appropriate electrolytic capacitor
should be added in parallel to the ceramic capacitor
to provide necessary damping for potential oscillations
caused by the inductance of the longer input power path
and input ceramic capacitor.
Inductor Selection
Three key inductor parameters must be specified for
operation with the device: inductance value (L), inductor
saturation current (ISAT), and DC resistance (RDCR). The
switching frequency and output voltage determine the
inductor value as follows:
VOUT
L = 0.9 × f
SW
where VOUT and fSW are nominal values and fSW is in
Hz. Select an inductor whose value is nearest to the value
calculated by the previous formula. Select a low-loss
inductor closest to the calculated value with acceptable
dimensions and having the lowest possible DC resistance.
www.maximintegrated.com
Maxim Integrated │ 18
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
The saturation current rating (ISAT) of the inductor must
be high enough to ensure that saturation can occur only
above the peak current-limit value of IPEAK-LIMIT.
Output-Capacitor Selection
X7R ceramic output capacitors are preferred due to their
stability over temperature in industrial applications. The
output capacitors are usually sized to support a step load
of 50% of the maximum output current in the application,
so the output-voltage deviation is contained to 3% of the
output-voltage change. The minimum required output
capacitance can be calculated as follows:
1
COUT = 2 ×
ISTEP × tRESPONSE
∆ VOUT
0.33
tRESPONSE ≅ f
C
where:
ISTEP = Load current step
tRESPONSE = Response time of the controller
ΔVOUT = Allowable output-voltage deviation
fC = Target closed-loop crossover frequency
fSW = Switching frequency.
Select fC to be 1/10th of fSW if the switching frequency is
less than or equal to 800kHz. If the switching frequency is
more than 800kHz, select fC to be 80kHz. Actual derating
of ceramic capacitors with DC bias voltage must be
considered while selecting the output capacitor. Derating
curves are available from all major ceramic capacitor
manufactures.
Soft-Start Capacitor Selection
The device implements adjustable soft-start operation to
reduce inrush current. A capacitor connected from the SS
pin to SGND programs the soft-start time. The selected
output capacitance (CSEL) and the output voltage (VOUT)
determine the minimum required soft-start capacitor as
follows:
For example, to program a 1ms soft-start time, a 5.6nF
capacitor should be connected from the SS pin to SGND.
Note that during start-up, the device operates at half the
programmed switching frequency until the output voltage
reaches 64.4% of set output nominal voltage.
Setting the Input
Undervoltage-Lockout Level
The device offers an adjustable input undervoltagelockout level. Set the voltage at which the device turns
on with a resistive voltage-divider connected from VINto
SGND (see Figure 1). Connect the center node of the
divider to EN/UVLO. Choose R1 to be 3.3MΩ and then
calculate R2 as follows:
R2 =
tSS =
CSS
5.55 × 10−6
(VINU − 1.215)
where, VINU is the input-voltage level at which the device
is required to turn on. Ensure that VINU is higher than 0.8
x VOUT to avoid hiccup during slow power-up (slower than
soft-start)/power-down. If the EN/UVLO pin is driven from
an external signal source, a series resistance of minimum
1kΩ is recommended to be placed between the output pin
of signal source and the EN/UVLO pin, to reduce voltage
ringing on the line.
Adjusting Output Voltage
Set the output voltage with a resistive voltage-divider
connected from the output-voltage node (VOUT) to SGND
(see Figure 2). Connect the center node of the divider
to the FB pin for MAX17630C. Connect the output
voltage node (VOUT) to the FB pin for MAX17630A and
MAX17630B. Use the following procedure to choose the
resistive voltage-divider values:
Calculate resistor RT from the output to the FB pin as
follows:
180
RT =
(fC x COUT_SEL)
VIN
CSS ≥ 28 × 10−6 × CSEL × VOUT
The soft-start time (tSS) is related to the capacitor
connected at SS (CSS) by the following equation:
R1 × 1.215
R1
EN/UVLO
R2
SGND
Figure 1. Setting the Input Undervoltage Lockout
www.maximintegrated.com
Maxim Integrated │ 19
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
where:
VOUT
RT is in kΩ
fC = Crossover frequency is in Hz
RT
COUT_SEL= Actual capacitance of selected output
capacitor at DC-bias voltage in F
Calculate resistor RB from the FB pin to SGND as follows:
RB =
(
RT × 0.9
VOUT − 0.9
)
FB
RB
SGND
RB is in kΩ.
Figure 2. Setting the Output Voltage
Power Dissipation
PCB Layout Guidelines
At a particular operating condition, the power losses
that lead to temperature rise of the part are estimated as
follows:
(
( 1 )) (
PLOSS = POUT × η − 1 − IOUT2 × RDCR
)
POUT = VOUT × IOUT
where:
POUT = Output power
η = Efficiency of the converter
RDCR = DC resistance of the inductor (see the Typical
Operating Characteristics for more information on
efficiency at typical operating conditions).
For a typical multilayer board, the thermal performance
metrics for the package are given below:
θJA = 38ºC/W
θJC = 10ºC/W
The junction temperature of the device can be estimated
at any given maximum ambient temperature (TA(MAX))
from the following equation:
TJ(MAX) = TA(MAX) + (θJA × PLOSS)
If the application has a thermal-management system that
ensures that the exposed pad of the device is maintained
at a given temperature (TEP(MAX)) by using proper heat
sinks, then the junction temperature of the device can be
estimated at any given maximum ambient temperature
as:
All connections carrying pulsed currents must be very
short and as wide as possible. The inductance of these
connections must be kept to an absolute minimum due
to the high di/dt of the currents. Since inductance of a
current-carrying loop is proportional to the area enclosed
by the loop, if the loop area is made very small, inductance
is reduced. Additionally, small-current loop areas reduce
radiated EMI.
A ceramic input filter capacitor should be placed close
to the VIN pins of the IC. This eliminates as much trace
inductance effects as possible and gives the IC a cleaner
voltage supply. A bypass capacitor for the VCC pin also
should be placed close to the pin to reduce effects of trace
impedance.
When routing the circuitry around the IC, the analog small
signal ground and the power ground for switching currents
must be kept separate. They should be connected
together at a point where switching activity is minimum.
This helps keep the analog ground quiet. The ground
plane should be kept continuous (unbroken) as far as
possible. No trace carrying high switching current should
be placed directly over any ground plane discontinuity.
PCB layout also affects the thermal performance of the
design. A number of thermal throughputs that connect to a
large ground plane should be provided under the exposed
pad of the part for efficient heat dissipation.
For a sample layout that ensures first pass success,
refer to the MAX17630 evaluation kit layout available at
www.maximintegrated.com.
TJ(MAX) = TEP(MAX) + (θJC × PLOSS)
Note: Junction temperatures greater than +125°C
degrades operating lifetimes.
www.maximintegrated.com
Maxim Integrated │ 20
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Application Circuits
Typical Application Circuit—Fixed 3.3V Output
EN/UVLO
VIN
VIN
RT
BST
C5
0.1µF
MODE/SYNC
LX
C3
2.2µF
VIN
4.5V TO 36V
C1
2.2µF
VCC
MAX17630A
SGND
LX
RESET
FB
SS
PGND
PGND
L1
10µH
VOUT
3.3V, 1A
C4
22µF
C1: 2.2µF/50V/X7R/1206 (C3216X7R1H225K160AE)
L1: 10µH (XAL5050-103ME)
C4: 22µF/25V/X7R/1210 (GRM32ER71E226ME15)
fSW : 400kHz
PWM MODE: CONNECT MODE/SYNC WITH SGND
DCM MODE: CONNECT MODE/SYNC WITH VCC
PFM MODE: LEAVE MODE/SYNC OPEN
EXTVCC
EP
C2
5600pF
Figure 3. Fixed 3.3V Output with 400kHz Switching Frequency
Typical Application Circuit—Fixed 5V Output
EN/UVLO
VIN
VIN
RT
BST
MODE/SYNC
LX
VCC
C3
2.2µF
C5
0.1µF
MAX17630B
SGND
LX
RESET
FB
SS
VIN
6.5V TO 36V
C1
2.2µF
PGND
PGND
L1
15µH
C4
22µF
C1: 2.2µF/50V/X7R/1206 (C3216X7R1H225K160AE)
L1: 15µH (XAL5050-153ME)
C4: 22µF/25V/X7R/1210 (GRM32ER71E226ME15)
fSW : 400kHz
PWM MODE: CONNECT MODE/SYNC WITH SGND
DCM MODE: CONNECT MODE/SYNC WITH VCC
PFM MODE: LEAVE MODE/SYNC OPEN
VOUT
5V, 1A
EXTVCC
C2
5600pF
EP
Figure 4. Fixed 5V Output with 400kHz Switching Frequency
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Maxim Integrated │ 21
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Application Circuits (continued)
Typical Application Circuit—Adjustable 3.3V Output
VIN
VIN
EN/UVLO
C1
2.2µF
VIN
RT
BST
C5
0.1µF
MODE/SYNC
LX
VCC
C3
2.2µF
4.5V TO 36V
MAX17630C
SGND
LX
RESET
FB
SS
PGND
PGND
L1
10µH
VOUT
3.3V, 1A
C4
22µF
EXTVCC
R1
243kΩ
C1: 2.2µF/50V/X7R/1206 (C3216X7R1H225K160AE)
L1: 10µH (XAL5050-103ME)
C4: 22µF/25V/X7R/1210 (GRM32ER71E226ME15)
fSW : 400kHz
PWM MODE: CONNECT MODE/SYNC WITH SGND
DCM MODE: CONNECT MODE/SYNC WITH VCC
PFM MODE: LEAVE MODE/SYNC OPEN
R2
91.1kΩ
EP
C2
5600pF
Figure 5. Adjustable 3.3V Output with 400kHz Switching Frequency
Typical Application Circuit—Adjustable 5V Output
EN/UVLO
VIN
VIN
RT
BST
MODE/SYNC
LX
VCC
C3
2.2µF
MAX17630C
SGND
LX
RESET
FB
SS
VIN
6.5V TO 36V
C1
2.2µF
PGND
C2
5600pF
PGND
C5
0.1µF
L1
15µH
C4
22µF
R1
243kΩ
VOUT
5V, 1A
C1: 2.2µF/50V/X7R/1206 (C3216X7R1H225K160AE)
L1: 15µH (XAL5050-153ME)
C4: 22µF/25V/X7R/1210 (GRM32ER71E226ME15)
fSW : 400kHz
PWM MODE: CONNECT MODE/SYNC WITH SGND
DCM MODE: CONNECT MODE/SYNC WITH VCC
PFM MODE: LEAVE MODE/SYNC OPEN
R2
53.6kΩ
EXTVCC
EP
Figure 6. Adjustable 5V Output with 400kHz Switching Frequency
www.maximintegrated.com
Maxim Integrated │ 22
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Application Circuits (continued)
Typical Application Circuit—Adjustable 5V Output with 1.5MHz Switching Frequency
EN/UVLO
R1
19.1kΩ
VIN
BST
MODE/SYNC
VCC
C3
2.2µF
VIN
RT
LX
MAX17630C
SGND
LX
RESET
FB
SS
VIN
8.5V TO 24V
C1
1µF
PGND
PGND
EXTVCC
C5
0.1µF
L1
4.7µH
C4
10µF
EP
VOUT
5V, 1A
R2
221kΩ
C1: 1µF/50V/X7R/1206 (HMK316B7105KL-T)
L1: 4.7µH/3mm x 3mm (74438335047)
C4: 10µF/10V/X7R/1206 (C3216X7R1C106K160AC)
fSW : 1.5MHz
PWM MODE: CONNECT MODE/SYNC WITH SGND
DCM MODE: CONNECT MODE/SYNC WITH VCC
PFM MODE: LEAVE MODE/SYNC OPEN
R3
48.5kΩ
C2
5600pF
Figure 7. Adjustable 5V Output with 1.5MHz Switching Frequency
Ordering Information
www.maximintegrated.com
PART NUMBER
OUTPUT
VOLTAGE (V)
MAX17630AATE+
3.3
16 TQFN 3mm x 3mm
MAX17630BATE+
5
16 TQFN 3mm x 3mm
MAX17630CATE+
Adjustable
16 TQFN 3mm x 3mm
PIN-PACKAGE
Maxim Integrated │ 23
MAX17630
4.5V to 36V, 1A, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Revision History
REVISION
NUMBER
REVISION
DATE
0
12/18
DESCRIPTION
Initial release
PAGES
CHANGED
—
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2018 Maxim Integrated Products, Inc. │ 24
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