产品描述the max17245 high-efficiency, synchronous step-down DC-DC converter with integrated mosfets operates over a 3.5V to 36v input voltage range with 42v input transient protection.
the max17245 high-efficiency, synchronous step-down DC-DC converter with integrated mosfets operates over a 3.5V to 36v input voltage range with 42v input transient protection.
Operating Temperature Range ....................... -40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10s) ................................. +300°C
Soldering Temperature (reflow) ....................................... +260°C
*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.
Package Thermal Characteristics
(Note 2)
TQFN
Junction-to-Ambient Thermal Resistance (B
JA
)...........35ºC/W
Junction-to-Case Thermal Resistance (B
JC
) ..............2.7ºC/W
TSSOP
Junction-to-Ambient Thermal Resistance (B
JA
)........38.3ºC/W
Junction-to-Case Thermal Resistance (B
JC
) .................3ºC/W
Note 1:
Self-protected against transient voltages exceeding these limits for ≤
50ns under normal operation and loads up to the maximum
rated output current.
Note 2:
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.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(V
SUP
= V
SUPSW
= 14V, V
EN
= 14V, L1 = 2.2µH, C
IN
= 4.7µF, C
OUT
= 22µF, C
BIAS
= 1µF, C
BST
= 0.1µF, R
FOSC
= 12kΩ,
T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
Supply Voltage
Line Transient Event
Supply Voltage
SYMBOL
V
SUP
, V
SUPSW
V
SUP_t_LT
t
t_LT
< 1s
Standby mode, no load, V
OUT
= 5V,
V
FSYNC
= 0V
Standby mode, no load, V
OUT
= 3.3V,
V
FSYNC
= 0V
V
EN
= 0V
V
SUP
= V
SUPSW
= 6V to 42V,
I
BIAS
= 0 to 10mA
V
BIAS
rising
4.7
2.95
28
22
5
5
3.15
450
+175
15
CONDITIONS
MIN
3.5
TYP
MAX
36
42
40
µA
35
10
5.4
3.40
650
µA
V
V
mV
°C
°C
UNITS
V
V
Supply Current
I
SUP_STANDBY
I
SHDN
V
BIAS
V
UVBIAS
Shutdown Supply Current
BIAS Regulator Voltage
BIAS Undervoltage Lockout
BIAS Undervoltage Lockout
Hysteresis
Thermal Shutdown Threshold
Thermal Shutdown Threshold
Hysteresis
www.maximintegrated.com
Maxim Integrated
│
2
MAX17245
3.5V–36V, 3.5A, Synchronous Buck Converter With
28μA Quiescent Current and Reduced EMI
Electrical Characteristics (continued)
(V
SUP
= V
SUPSW
= 14V, V
EN
= 14V, L1 = 2.2µH, C
IN
= 4.7µF, C
OUT
= 22µF, C
BIAS
= 1µF, C
BST
= 0.1µF, R
FOSC
= 12kΩ,
T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
OUTPUT VOLTAGE (OUT)
PWM Mode Output Voltage
PFM Mode Output Voltage
Load Regulation
Line Regulation
I
BST_ON
I
BST_OFF
I
LX
I
PFM_TH
V
OUT_5V
V
OUT_3.3V
V
OUT_PFM_5V
V
OUT_PFM_3.3V
V
FB
= V
BIAS,
6V < V
SUPSW
< 36V,
fixed-frequency mode (Notes 4, 5)
No load, V
FB
= V
BIAS
, PFM mode
(Note 6)
V
FB
= V
BIAS
, 300mA < I
LOAD
< 3.5A
V
FB
= V
BIAS
, 6V < V
SUPSW
< 36V
(Note 5)
High-side MOSFET on, V
BST
- V
LX
= 5V
High-side MOSFET off, V
BST
- V
LX
= 5V,
T
A
= +25°C
Peak inductor current
R
FOSC
= 12kΩ
T
A
= +25°C
Spread spectrum enabled
R
ON_H
I
LX
= 1A, V
BIAS
= 5V
High-side MOSFET off, V
SUP
= 36V,
V
LX
= 0V, T
A
= +25°C
R
ON_L
I
LX
= 0.2A, V
BIAS
= 5V
V
LX
= 36V, T
A
= +25°C
200
4.2
5.2
4
400
f
OSC
±6%
100
1
1.5
220
3
3
1
mΩ
µA
Ω
µA
500
1
4.9
3.234
4.9
3.234
5
3.3
5
3.3
0.5
0.02
1.5
2
5
6.2
5.1
3.366
5.15
3.4
V
V
%
%/V
mA
µA
A
ns
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
BST Input Current
LX Current Limit
LX Rise Time
PFM Mode Current Threshold
Spread Spectrum
High-Side Switch
On-Resistance
High-Side Switch Leakage
Current
Low-Side Switch
On-Resistance
Low-Side Switch
Leakage Current
TRANSCONDUCTANCE AMPLIFIER (COMP)
FB Input Current
FB Regulation Voltage
FB Line Regulation
Transconductance
(from FB to COMP)
Minimum On-Time
Maximum Duty Cycle
OSCILLATOR FREQUENCY
Oscillator Frequency
R
FOSC
= 73.2kΩ
R
FOSC
= 12kΩ
340
2.0
400
2.2
460
2.4
kHz
MHz
I
FB
V
FB
∆V
LINE
g
m
t
ON_MIN
DC
MAX
FB connected to an external resistor
divider, 6V < V
SUPSW
< 36V (Note 7)
6V < V
SUPSW
< 36V
V
FB
= 1V, V
BIAS
= 5V
(Note 5)
0.99
20
1.0
0.02
700
80
98
100
1.015
nA
V
%/V
µS
ns
%
www.maximintegrated.com
Maxim Integrated
│
3
MAX17245
3.5V–36V, 3.5A, Synchronous Buck Converter With
28μA Quiescent Current and Reduced EMI
Electrical Characteristics (continued)
(V
SUP
= V
SUPSW
= 14V, V
EN
= 14V, L1 = 2.2µH, C
IN
= 4.7µF, C
OUT
= 22µF, C
BIAS
= 1µF, C
BST
= 0.1µF, R
FOSC
= 12kΩ,
T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 3)
PARAMETER
External Input Clock
Acquisition time
External Input Clock
Frequency
External Input Clock High
Threshold
External Input Clock Low
Threshold
Soft-Start Time
ENABLE INPUT (EN)
Enable Input High Threshold
Enable Input Low Threshold
Enable Threshold Voltage
Hysteresis
Enable Input Current
POWER GOOD (PGOOD)
PGOOD
Switching Level
PGOOD
Debounce Time
PGOOD
Output Low Voltage
PGOOD
Leakage Current
SYNCOUT Low Voltage
SYNCOUT Leakage Current
FSYNC Leakage Current
OVERVOLTAGE PROTECTION
Overvoltage Protection
Threshold
Note
Note
Note
Note
Note
Note
3:
4:
5:
6:
7:
8:
V
OUT
rising (monitored at FB pin)
V
OUT
falling (monitored at FB pin)
105
102
%
I
SINK
= 5mA
V
OUT
in regulation, T
A
= +25°C
I
SINK
= 5mA
T
A
= +25°C
T
A
= +25°C
V
TH_RISING
V
TH_FALLING
V
FB
rising, V
PGOOD
= high
V
FB
falling, V
PGOOD
= low
93
90
10
95
92
25
97
94
50
0.4
1
0.4
1
1
%V
FB
µs
V
µA
V
µA
µA
V
EN_HI
V
EN_LO
V
EN_HYS
I
EN
T
A
= +25°C
0.2
0.1
1
2.4
0.6
V
µA
V
V
FSYNC_HI
V
FSYNC_LO
t
SS
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
EXTERNAL CLOCK INPUT (FSYNC)
t
FSYNC
R
FOSC
= 12kΩ (Note 8)
V
FSYNC
rising
V
FSYNC
falling
5.6
8
1.8
1.4
0.4
12
1
2.6
Cycles
MHz
V
V
ms
Limits are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by design.
Device not in dropout condition.
Filter circuit required, see the
Typical Application Circuit.
Guaranteed by design; not production tested.
FB regulation voltage is 1%, 1.01V (max), for -40°C < T
A
< +105°C.
Contact the factory for SYNC frequency outside the specified range.
the max17245 high-efficiency, synchronous step-down DC-DC converter with integrated mosfets operates over a 3.5V to 36v input voltage range with 42v input transient protection.
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