Operating Temperature Range .................... -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
*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 opera-
tion 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
) ..........35NC/W
Junction-to-Case Thermal Resistance (B
JC
) ..............2.7NC/W
TSSOP
Junction-to-Ambient Thermal Resistance (B
JA
) .......38.3NC/W
Junction-to-Case Thermal Resistance (B
JC
) .................3NC/W
Note 1:
Self-protected against transient voltages exceeding these limits for ≤ 50ns under normal operation and loads up to the maxi-
mum 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 = 2.2FH, C
IN
= 4.7FF, C
OUT
= 22FF, C
BIAS
= 1FF, C
BST
= 0.1FF, R
FOSC
= 12kI,
T
A
= T
J
= -40NC to +125NC, unless otherwise noted. Typical values are at T
A
= +25NC.)
PARAMETER
Supply Voltage
Load-Dump Event Supply
Voltage
SYMBOL
V
SUP,
V
SUPSW
V
SUP_LD
t
LD
< 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
MAX16935/39
MAX16935C
MAX16935/39
MAX16935C
28
32
22
23
5
5
3.15
450
+175
15
CONDITIONS
MIN
3.5
TYP
MAX
36
42
40
45
35
36
10
5.4
3.40
650
FA
V
V
mV
NC
NC
FA
UNITS
V
V
Supply Current
I
SUP_STANDBY
Shutdown Supply Current
BIAS Regulator Voltage
BIAS Undervoltage Lockout
BIAS Undervoltage-Lockout
Hysteresis
Thermal-Shutdown Threshold
Thermal-Shutdown Threshold
Hysteresis
I
SHDN
V
BIAS
V
UVBIAS
www.maximintegrated.com
Maxim Integrated
│
2
MAX16935/MAX16939
36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
Electrical Characteristics (continued)
(V
SUP
= V
SUPSW
= 14V, V
EN
= 14V, L1 = 2.2FH, C
IN
= 4.7FF, C
OUT
= 22FF, C
BIAS
= 1FF, C
BST
= 0.1FF, R
FOSC
= 12kI,
T
A
= T
J
= -40NC to +125NC, unless otherwise noted. Typical values are at T
A
= +25NC.)
PARAMETER
OUTPUT VOLTAGE (OUT)
FPWM Mode Output Voltage
Skip Mode Output Voltage
Load Regulation
Line Regulation
I
BST_ON
BST Input Current
LX Current Limit
LX Rise Time
Skip 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
= 73.2kI
R
FOSC
= 12kI
340
2.0
400
2.2
460
2.4
kHz
MHz
I
FB
V
FB
DV
LINE
g
m
t
ON_MIN
DC
MAX
FB connected to an external resistor
divider, 6V < V
SUPSW
< 36V (Note 6)
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
FS
ns
%
R
ON_L
R
ON_H
I
SKIP_TH
I
BST_OFF
I
LX
V
OUT_5V
V
OUT_3.3V
V
OUT_SKIP_5V
V
OUT_SKIP_3.3V
V
FB
= V
BIAS,
6V < V
SUPSW
< 36V,
fixed-frequency mode (Notes 3, 4)
No load, V
FB
= V
BIAS,
skip mode (Note
5)
V
FB
= V
BIAS
, 300mA < I
LOAD
< 3.5A
V
FB
= V
BIAS
, 6V < V
SUPSW
< 36V
(Note 4)
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
= 12kW
T
A
= +25°C
MAX16935
MAX16939
150
200
4.2
5.2
4
300
400
f
OSC
Q6%
100
1
1.5
220
3
3
1
mI
FA
I
FA
400
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
FA
A
ns
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Spread spectrum enabled
I
LX
= 1A, V
BIAS
= 5V
High-side MOSFET off, V
SUP
= 36V,
V
LX
= 0V, T
A
= +25NC
I
LX
= 0.2A, V
BIAS
= 5V
V
LX
= 36V, T
A
= +25NC
www.maximintegrated.com
Maxim Integrated
│
3
MAX16935/MAX16939
36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
Electrical Characteristics (continued)
(V
SUP
= V
SUPSW
= 14V, V
EN
= 14V, L1 = 2.2FH, C
IN
= 4.7FF, C
OUT
= 22FF, C
BIAS
= 1FF, C
BST
= 0.1FF, R
FOSC
= 12kI,
T
A
= T
J
= -40NC to +125NC, unless otherwise noted. Typical values are at T
A
= +25NC.)
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)
V
TH_RISING
PGOOD Switching Level
V
FB
rising, V
PGOOD
= high
V
FB
falling, V
PGOOD
= low
(MAX16935C, V
OUT
= 5V)
V
FB
falling, V
PGOOD
= low
V
FB
falling, V
PGOOD
= low (MAX16935C)
V
OUT
rising edge (MAX16935B)
I
SINK
= 5mA
V
OUT
in regulation, T
A
= +25NC
I
SINK
= 5mA
T
A
= +25NC
T
A
= +25NC
V
OUT
rising (monitored
at FB pin)
V
OUT
falling (monitored
at FB pin)
MAX16935
MAX16939
MAX16935
MAX16939
107
105
105
102
%
93
4.5
90
90.5
10
200
92
92.5
25
300
0.4
1
0.4
1
1
94
94.5
50
95
97
%V
FB
V
%V
FB
%V
FB
Fs
Fs
V
FA
V
FA
FA
V
EN_HI
V
EN_LO
V
EN_HYS
I
EN
T
A
= +25NC
0.2
0.1
1
2.4
0.6
V
FA
V
V
FSYNC_HI
V
FSYNC_LO
t
SS
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
EXTERNAL CLOCK INPUT (FSYNC)
t
FSYNC
R
FOSC
= 12kI (Note 7)
V
FSYNC
rising
V
FSYNC
falling
5.6
8
1.8
1.4
0.4
12
1
2.6
Cycles
MHz
V
V
ms
V
TH_FALLING
PGOOD Debounce Time
PGOOD Assertion Delay
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
3:
4:
5:
6:
7:
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.
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