General Description
The MAX16935/MAX16939 are 3.5A current-mode step-
down converters with integrated high-side and low-
side MOSFETs designed to operate with an external
Schottky diode for better efficiency. The low-side MOSFET
enables fixed-frequency forced-PWM (FPWM) operation
under light-load applications. The devices operate with
input voltages from 3.5V to 36V, while using only 28FA
quiescent current at no load. The switching frequency is
resistor programmable from 220kHz to 2.2MHz and can
be synchronized to an external clock. The devices’ output
voltage is available as 3.3V/5V fixed or adjustable from
1V to 10V. The wide input voltage range along with its
ability to operate at 98% duty cycle during undervoltage
transients make the devices ideal for automotive and
industrial applications.
Under light-load applications, the FSYNC logic input
allows the devices to either operate in skip mode for
reduced current consumption or fixed-frequency FPWM
mode to eliminate frequency variation to minimize
EMI. Fixed-frequency FPWM mode is extremely use-
ful for power supplies designed for RF transceivers
where tight emission control is necessary. Protection
features include cycle-by-cycle current limit and thermal
shutdown with automatic recovery. Additional features
include a power-good monitor to ease power-supply
sequencing and a 180N out-of-phase clock output relative
to the internal oscillator at SYNCOUT to create cascaded
power supplies with multiple devices.
The MAX16935/MAX16939 operate over the -40NC
to +125NC automotive temperature range and are
available in 16-pin (5mm x 5mm) TQFN-EP and 16-pin
TSSOP-EP packages.
Applications
●Point-of-Load Applications
●Distributed DC Power Systems
●Navigation and Radio Head Units
Benets and Features
●Integration and High-Switching Frequency Saves
Space
• Integrated 3.5A High-Side Switch
• Low-BOM-Count Current-Mode Control
Architecture
• Fixed Output Voltage with ±2% Accuracy or
Externally Resistor Adjustable (1V to 10V)
• 220kHz to 2.2MHz Switching Frequency with
Three Operation Modes (Skip Mode, Forced
Fixed-Frequency Operation, and External
Frequency Synchronization)
• Automatic LX Slew-Rate Adjustment for Optimum
E󰀩ciency Across Operating Frequency Range
●180° Out-of-Phase Clock Output at SYNCOUT
Enables Cascaded Power Supplies for Increased
Power Output
●Spread-Spectrum Frequency Modulation Reduces
EMI Emissions
●Wide Input Voltage Range Supports Automotive
Applications
• 3.5V to 36V Input Voltage Range (42V Tolerant)
• Enable Input Compatible from 3.3V Logic Level
to 42V
●Robust Performance Supports Wide Range of
Automotive Applications
• -40°C to +125°C Automotive Temperature Range
• Thermal-Shutdown Protection
• AEC-Q100 Qualied
●Power-Good Output Allows Power-Supply
Sequencing
●Tight Overvoltage Protection Provides Smaller
Overshoot Voltages (MAX16939)
19-6868; Rev 17; 1/18
Ordering Information/Selector Guide and Typical
Application Circuit appear at end of data sheet.
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
EVALUATION KIT AVAILABLE
SUP, SUPSW, EN to PGND ................................... -0.3V to +42V
LX (Note 1) ............................................................-0.3V to +42V
SUP to SUPSW .....................................................-0.3V to +0.3V
BIAS to AGND .........................................................-0.3V to +6V
SYNCOUT, FOSC, COMP, FSYNC,
PGOOD, FB to AGND ........................-0.3V to (VBIAS + 0.3V)
OUT to PGND ........................................................ -0.3V to +12V
BST to LX (Note 1) ..................................................-0.3V to +6V
AGND to PGND ................................................... -0.3V to + 0.3V
LX Continuous RMS Current ................................................3.5A
Output Short-Circuit Duration .................................... Continuous
Continuous Power Dissipation (TA = +70NC)*
TQFN (derate 28.6mW/NC above +70NC)...............2285.7mW
TSSOP (derate 26.1mW/NC above +70NC).............2088.8mW
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).
TQFN
Junction-to-Ambient Thermal Resistance (BJA) ..........35NC/W
Junction-to-Case Thermal Resistance (BJC) ..............2.7NC/W
TSSOP
Junction-to-Ambient Thermal Resistance (BJA) .......38.3NC/W
Junction-to-Case Thermal Resistance (BJC) .................3NC/W
(Note 2)
(VSUP = VSUPSW = 14V, VEN = 14V, L1 = 2.2FH, CIN = 4.7FF, COUT = 22FF, CBIAS = 1FF, CBST = 0.1FF, RFOSC = 12kI,
TA = TJ = -40NC to +125NC, unless otherwise noted. Typical values are at TA = +25NC.)
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.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage VSUP, VSUPSW 3.5 36 V
Load-Dump Event Supply
Voltage VSUP_LD tLD < 1s 42 V
Supply Current ISUP_STANDBY
Standby mode, no
load, VOUT = 5V,
VFSYNC = 0V
MAX16935/39 28 40
FA
MAX16935C 32 45
Standby mode, no
load, VOUT = 3.3V,
VFSYNC = 0V
MAX16935/39 22 35
MAX16935C 23 36
Shutdown Supply Current ISHDN VEN = 0V 5 10 FA
BIAS Regulator Voltage VBIAS VSUP = VSUPSW = 6V to 42V,
IBIAS = 0 to 10mA 4.7 5 5.4 V
BIAS Undervoltage Lockout VUVBIAS VBIAS rising 2.95 3.15 3.40 V
BIAS Undervoltage-Lockout
Hysteresis 450 650 mV
Thermal-Shutdown Threshold +175 NC
Thermal-Shutdown Threshold
Hysteresis 15 NC
Absolute Maximum Ratings
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
Electrical Characteristics
www.maximintegrated.com Maxim Integrated
│
2
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
(VSUP = VSUPSW = 14V, VEN = 14V, L1 = 2.2FH, CIN = 4.7FF, COUT = 22FF, CBIAS = 1FF, CBST = 0.1FF, RFOSC = 12kI,
TA = TJ = -40NC to +125NC, unless otherwise noted. Typical values are at TA = +25NC.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT VOLTAGE (OUT)
FPWM Mode Output Voltage VOUT_5V VFB = VBIAS, 6V < VSUPSW < 36V,
fixed-frequency mode (Notes 3, 4)
4.9 5 5.1 V
VOUT_3.3V 3.234 3.3 3.366
Skip Mode Output Voltage VOUT_SKIP_5V No load, VFB = VBIAS, skip mode (Note
5)
4.9 5 5.15 V
VOUT_SKIP_3.3V 3.234 3.3 3.4
Load Regulation VFB = VBIAS, 300mA < ILOAD < 3.5A 0.5 %
Line Regulation VFB = VBIAS, 6V < VSUPSW < 36V
(Note 4) 0.02 %/V
BST Input Current
IBST_ON High-side MOSFET on, VBST - VLX = 5V 1 1.5 2 mA
IBST_OFF High-side MOSFET off, VBST - VLX = 5V,
TA = +25°C5FA
LX Current Limit ILX Peak inductor current 4.2 5.2 6.2 A
LX Rise Time RFOSC = 12kW4 ns
Skip Mode Current Threshold ISKIP_TH TA = +25°CMAX16935 150 300 400 mA
MAX16939 200 400 500
Spread Spectrum Spread spectrum enabled fOSC Q6%
High-Side-Switch
On-Resistance RON_H ILX = 1A, VBIAS = 5V 100 220 mI
High-Side-Switch Leakage
Current
High-side MOSFET off, VSUP = 36V,
VLX = 0V, TA = +25NC1 3 FA
Low-Side Switch
On-Resistance RON_L ILX = 0.2A, VBIAS = 5V 1.5 3 I
Low-Side Switch
Leakage Current VLX = 36V, TA = +25NC 1 FA
TRANSCONDUCTANCE AMPLIFIER (COMP)
FB Input Current IFB 20 100 nA
FB Regulation Voltage VFB FB connected to an external resistor
divider, 6V < VSUPSW < 36V (Note 6) 0.99 1.0 1.015 V
FB Line Regulation DVLINE 6V < VSUPSW < 36V 0.02 %/V
Transconductance
(from FB to COMP) gmVFB = 1V, VBIAS = 5V 700 FS
Minimum On-Time tON_MIN (Note 5) 80 ns
Maximum Duty Cycle DCMAX 98 %
OSCILLATOR FREQUENCY
Oscillator Frequency RFOSC = 73.2kI340 400 460 kHz
RFOSC = 12kI2.0 2.2 2.4 MHz
Electrical Characteristics (continued)
www.maximintegrated.com Maxim Integrated
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3
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
(VSUP = VSUPSW = 14V, VEN = 14V, L1 = 2.2FH, CIN = 4.7FF, COUT = 22FF, CBIAS = 1FF, CBST = 0.1FF, RFOSC = 12kI,
TA = TJ = -40NC to +125NC, unless otherwise noted. Typical values are at TA = +25NC.)
Note 3: Device not in dropout condition.
Note 4: Filter circuit required, see the Typical Application Circuit.
Note 5: Guaranteed by design; not production tested.
Note 6: FB regulation voltage is 1%, 1.01V (max), for -40°C < TA < +105°C.
Note 7: Contact the factory for SYNC frequency outside the specified range.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
EXTERNAL CLOCK INPUT (FSYNC)
External Input Clock
Acquisition time tFSYNC 1 Cycles
External Input Clock
Frequency RFOSC = 12kI (Note 7) 1.8 2.6 MHz
External Input Clock High
Threshold VFSYNC_HI VFSYNC rising 1.4 V
External Input Clock Low
Threshold VFSYNC_LO VFSYNC falling 0.4 V
Soft-Start Time tSS 5.6 8 12 ms
ENABLE INPUT (EN)
Enable Input High Threshold VEN_HI 2.4 V
Enable Input Low Threshold VEN_LO 0.6
Enable Threshold Voltage
Hysteresis VEN_HYS 0.2 V
Enable Input Current IEN TA = +25NC0.1 1FA
POWER GOOD (PGOOD)
PGOOD Switching Level
VTH_RISING VFB rising, VPGOOD = high 93 95 97 %VFB
VTH_FALLING
VFB falling, VPGOOD = low
(MAX16935C, VOUT = 5V) 4.5 V
VFB falling, VPGOOD = low 90 92 94 %VFB
VFB falling, VPGOOD = low (MAX16935C) 90.5 92.5 94.5 %VFB
PGOOD Debounce Time 10 25 50 Fs
PGOOD Assertion Delay VOUT rising edge (MAX16935B) 200 300 Fs
PGOOD Output Low Voltage ISINK = 5mA 0.4 V
PGOOD Leakage Current VOUT in regulation, TA = +25NC 1 FA
SYNCOUT Low Voltage ISINK = 5mA 0.4 V
SYNCOUT Leakage Current TA = +25NC 1 FA
FSYNC Leakage Current TA = +25NC 1 FA
OVERVOLTAGE PROTECTION
Overvoltage-Protection
Threshold
VOUT rising (monitored
at FB pin)
MAX16935 107
%
MAX16939 105
VOUT falling (monitored
at FB pin)
MAX16935 105
MAX16939 102
Electrical Characteristics (continued)
www.maximintegrated.com Maxim Integrated
│
4
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
(VSUP = VSUPSW = 14V, VEN = 14V, VOUT = 5V, VFYSNC = 0V, RFOSC = 12kI, TA = +25NC, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
toc09
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
2616
15
20
25
30
35
40
45
50
10
63
6
5V/2.2MHz
SKIP MODE
SWITCHING FREQUENCY vs. RFOSC
toc08
RFOSC (kΩ)
SWITCHING FREQUENCY (MHz)
1027242
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
0
12 132
fSW vs. TEMPERATURE
toc07
TEMPERATURE (°C)
fSW (MHz)
11095-25 -10 5 35 50 6520 80
2.04
2.08
2.12
2.16
2.20
2.24
2.28
2.00
-40 125
VIN = 14V,
PWM MODE
VOUT = 5V
425
427
429
431
433
435
437
439
441
443
445
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
f
SW
(kHz)
ILOAD (A)
fSW vs. LOAD CURRENT
V
IN
= 14V,
PWM MODE
VOUT = 3.3V
VOUT = 5V
toc06
2.10
2.12
2.14
2.16
2.18
2.20
2.22
2.24
2.26
2.28
2.30
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
f
SW
(MHz)
ILOAD (A)
fSW vs. LOAD CURRENT
VIN = 14V,
PWM MODE
VOUT = 3.3V
VOUT = 5V
toc05
4.90
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
V
OUT
(V)
ILOAD (A)
VOUT LOAD REGULATION
VOUT = 5V, VIN = 14V
PWM MODE
400kHz
2.2MHz
toc04
4.90
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
5.10
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
V
OUT
(V)
ILOAD (A)
VOUT LOAD REGULATION
V
OUT
= 5V, V
IN
= 14V
SKIP MODE
400kHz
2.2MHz
toc03
0
10
20
30
40
50
60
70
80
90
100
0.0000 0.0010 0.1000 10.0000
EFFICIENCY (%)
LOAD CURRENT (A)
EFFICIENCY vs. LOAD CURRENT
fSW = 400kHz, VIN = 14V
SKIP MODE
PWM MODE
3.3V
3.3V
5V
5V
toc02
0
10
20
30
40
50
60
70
80
90
100
0.0000 0.0010 0.1000 10.0000
EFFICIENCY (%)
LOAD CURRENT (A)
EFFICIENCY vs. LOAD CURRENT
fSW = 2.2MHz, VIN = 14V
SKIP MODE
PWM MODE
3.3V
3.3V
5V
5V
toc01
Typical Operating Characteristics
Maxim Integrated
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5
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MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converter
with 28µA Quiescent Current
(VSUP = VSUPSW = 14V, VEN = 14V, VOUT = 5V, VFYSNC = 0V, RFOSC = 12kI, TA = +25NC, unless otherwise noted.)
DIPS AND DROPS TEST
toc18
VIN
VOUT
VLX
VPGOOD
5V/2.2MHz
10ms
10V/div
0V
0V
5V/div
10V/div
0V
0V
5V/div
SYNC FUNCTION
toc17
VLX
VFSYNC
200ns
5V/div
2V/div
10V/div
0V
5V/div
0V
2A/div
0V
toc15
VIN
VOUT
SLOW VIN RAMP BEHAVIOR
ILOAD
VPGOOD
5V/div
0V
10V/div
0V
5V/div
0V
1A/div
0V
toc14
VIN
VOUT
FULL-LOAD STARTUP BEHAVIOR
ILOAD
VPGOOD
5V/div
0V
VOUT vs. VIN
toc13
VIN (V)
VOUT (V)
30241812
4.97
4.99
5.01
5.03
5.05
4.95
63
6
5V/400kHz
PWM MODE
ILOAD = 0A
VOUT vs. VIN
toc12
VIN (V)
VOUT (V)
3630241812
4.92
4.94
4.96
4.98
5.00
5.02
5.04
5.06
5.08
4.90
64
2
5V/2.2MHz
PWM MODE
ILOAD = 0A
VBIAS vs. TEMPERATURE
toc11
TEMPERATURE (°C)
VBIAS (V)
1109565 80-10 5 20 35 50-25
4.91
4.92
4.93
4.94
4.95
4.96
4.97
4.98
4.99
5.00
5.01
5.02
4.90
-40 125
ILOAD = 0A
VIN = 14V,
PWM MODE
SHDN CURRENT vs. SUPPLY VOLTAGE
toc10
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
30241812
1
2
3
4
5
6
7
8
9
10
0
63
6
5V/2.2MHz
SKIP MODE
Typical Operating Characteristics (continued)
Maxim Integrated
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6
www.maximintegrated.com
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converter
with 28µA Quiescent Current
(VSUP = VSUPSW = 14V, VEN = 14V, VOUT = 5V, VFYSNC = 0V, RFOSC = 12kI, TA = +25NC, unless otherwise noted.)
COLD CRANK
toc19
VIN
VOUT
VPGOOD
400ms
2V/div
0V
2V/div
2V/div
200mV/
div
2A/
div
0A
toc21
VOUT
LOAD
CURRENT
LOAD DUMP
toc20
VIN
VOUT
100ms
10V/div
0V
0V
5V/div
SHORT CIRCUIT IN PWM MODE
toc22
VOUT
INDUCTOR
CURRENT
10ms
2V/div
0V
0V
5V/div
2A/div
0A
VPGOOD
Typical Operating Characteristics (continued)
Maxim Integrated
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MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converter
with 28µA Quiescent Current
PIN NAME FUNCTION
TQFN TSSOP
16 1 SYNCOUT
Open-Drain Clock Output. SYNCOUT outputs 180N out-of-phase signal relative to the
internal oscillator. Connect to OUT with a resistor between 100I and 1kW for 2MHz
operation. For low frequency operation, use a resistor between 1kW and 10kW.
1 2 FSYNC
Synchronization Input. The device synchronizes to an external signal applied to
FSYNC. Connect FSYNC to AGND to enable skip mode operation. Connect to BIAS or
to an external clock to enable fixed-frequency forced PWM mode operation.
2 3 FOSC Resistor-Programmable Switching Frequency Setting Control Input. Connect a resistor
from FOSC to AGND to set the switching frequency.
3 4 OUT Switching Regulator Output. OUT also provides power to the internal circuitry when
the output voltage of the converter is set between 3V to 5V during standby mode.
4 5 FB Feedback Input. Connect an external resistive divider from OUT to FB and AGND to
set the output voltage. Connect to BIAS to set the output voltage to 5V.
5 6 COMP Error Amplifier Output. Connect an RC network from COMP to AGND for stable
operation. See the Compensation Network section for more information.
6 7 BIAS Linear Regulator Output. BIAS powers up the internal circuitry. Bypass with a 1FF
capacitor to ground.
7 8 AGND Analog Ground
8 9 BST High-Side Driver Supply. Connect a 0.1FF capacitor between LX and BST for
proper operation.
9 10 EN SUP Voltage Compatible Enable Input. Drive EN low to disable the device. Drive EN
high to enable the device.
+
TSSOP
13
4
LX
OUT
14
3
LX
FOSC
15
2
PGND
FSYNC
16
1
TOP VIEW
PGOODSYNCOUT
10
7
EN
BIAS
11
6
SUP
COMP
9
8
BST
AGND
12
5
SUPSW
FB
EP
MAX16935
MAX16939
+EP
15
16
14
13
6
5
7
FOSC
FB
8
FSYNC
SUPSW
EN
LX
12
PGND
4
12 11 9
SYNCOUT
BST
AGND
BIAS
COMP
OUT SUP
3
10
LX
TQFN
PGOOD
MAX16935
MAX16939
Pin Descriptions
Pin Congurations
www.maximintegrated.com Maxim Integrated
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8
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
Detailed Description
The MAX16935/MAX16939 are 3.5A current-mode step-
down converters with integrated high-side and low-side
MOSFETs designed to operate with an external Schottky
diode for better efficiency. The low-side MOSFET
enables fixed-frequency forced-PWM (FPWM) operation
under light-load applications. The devices operate with
input voltages from 3.5V to 36V, while using only 28FA
quiescent current at no load. The switching frequency
is resistor programmable from 220kHz to 2.2MHz and
can be synchronized to an external clock. The output
voltage is available as 3.3V/5V fixed or adjustable from
1V to 10V. The wide input voltage range along with its
ability to operate at 98% duty cycle during undervoltage
transients make the devices ideal for automotive and
industrial applications.
Under light-load applications, the FSYNC logic input
allows the devices to either operate in skip mode for
reduced current consumption or fixed-frequency FPWM
mode to eliminate frequency variation to minimize EMI.
Fixed frequency FPWM mode is extremely useful for
power supplies designed for RF transceivers where
tight emission control is necessary. Protection
features include cycle-by-cycle current limit,
overvoltage protection, and thermal shutdown with auto-
matic recovery. Additional features include a power-
good monitor to ease power-supply sequencing
and a 180N out-of-phase clock output relative to the
internal oscillator at SYNCOUT to create cascaded power
supplies with multiple devices.
Wide Input Voltage Range
The devices include two separate supply inputs (SUP and
SUPSW) specified for a wide 3.5V to 36V input voltage
range. VSUP provides power to the device and VSUPSW
provides power to the internal switch. When the device
is operating with a 3.5V input supply, conditions such as
cold crank can cause the voltage at SUP and SUPSW to
drop below the programmed output voltage. Under such
conditions, the device operate in a high duty-cycle mode
to facilitate minimum dropout from input to output.
In applications where the input voltage exceeds 25V,
output is ≤ 5V, operating frequency is ≥ 1.8MHz and the
IC is selected to be in FPWM mode by either forcing the
FSYNC pin high, or using an external clock, pulse skipping
is observed on the LX pin. This happens due to insufficient
minimum on time. Under certain load conditions (typically
< 1A), a filter circuit from LX to GND is required to maintain
the output voltage within the expected data sheet limits. A
typical filter value of RFILTER = 1I, CFILTER = 220pF (see
the Typical Application Circuit) is sufficient to filter out the
noise and maintain the output voltage within data sheet
limits. This extra filter on the LX pin of the IC has no impact
on efficiency.
Linear Regulator Output (BIAS)
The devices include a 5V linear regulator (BIAS) that
provides power to the internal circuit blocks. Connect a
1FF ceramic capacitor from BIAS to AGND.
PIN NAME FUNCTION
TQFN TSSOP
10 11 SUP
Voltage Supply Input. SUP powers up the internal linear regulator. Bypass SUP to
PGND with a 4.7FF ceramic capacitor. It is recommended to add a placeholder for
an RC filter to reduce noise on the internal logic supply (see the Typical Application
Circuit)
11 12 SUPSW Internal High-Side Switch Supply Input. SUPSW provides power to the internal switch.
Bypass SUPSW to PGND with 0.1FF and 4.7FF ceramic capacitors.
12, 13 13, 14 LX Inductor Switching Node. Connect a Schottky diode between LX and AGND.
14 15 PGND Power Ground
15 16 PGOOD Open-Drain, Active-Low Power-Good Output. PGOOD asserts when VOUT is above
95% regulation point. PGOOD goes low when VOUT is below 92% regulation point.
— — EP
Exposed Pad. Connect EP to a large-area contiguous copper ground plane for
effective power dissipation. Do not use as the only IC ground connection. EP must be
connected to PGND.
Pin Descriptions (continued)
www.maximintegrated.com Maxim Integrated
│
9
MAX16935/MAX16939 36V, 3.5A, 2.2MHz Step-Down Converters
with 28µA Quiescent Current
Power-Good Output (PGOOD)
The devices feature an open-drain power-good output,
PGOOD. PGOOD asserts when VOUT rises above 95%
of its regulation voltage. PGOOD deasserts when VOUT
drops below 92% of its regulation voltage. Connect
PGOOD to BIAS with a 10kI resistor.
Overvoltage Protection (OVP)
If the output voltage reaches the OVP threshold, the
high-side switch is forced off and the low-side switch
is forced on until negative-current limit is reached. After
negative-current limit is reached, both the high-side and
low-side switches are turned off. The MAX16939 offers a
lower voltage threshold for applications requiring tighter
limits of protection.
The MAX16935C offers overvoltage protection in all
modes of operation and protects the output against
reaching > 110% of the regulated voltage. If MAX16935C
output reaches overvoltage-protection thresholds it turns
on the active pulldown on the output (100Ω, typ) to
prevent the output from rising above 110% of regu-
lated voltage. This does not protect against a hard-short
across the HSFET of the IC.
Synchronization Input (FSYNC)
FSYNC is a logic-level input useful for operating mode
selection and frequency control. Connecting FSYNC to
BIAS or to an external clock enables fixed-frequency
FPWM operation. Connecting FSYNC to AGND enables
skip mode operation.
The external clock frequency at FSYNC can be higher
or lower than the internal clock by 20%. Ensure the duty
cycle of the external clock used has a minimum pulse
width of 100ns. The devices synchronize to the external
Figure 1. Internal Block Diagram
FBSW
OUT COMP PGOOD EN
FB
SOFT
START
SLOPE
COMP
FBOK
EAMP
HSD
LSD
AON
LOGIC
CS
REF
HVLDO
SWITCH
OVER
PWM
SUP BIAS
BST
SUPSW
LX
PGND
SYNCOUT
BIAS
FSYNC FOSC AGND
OSC
MAX16935
MAX16939
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clock within one cycle. When the external clock signal
at FSYNC is absent for more than two clock cycles, the
devices revert back to the internal clock.
System Enable (EN)
An enable control input (EN) activates the device from its
low-power shutdown mode. EN is compatible with inputs
from automotive battery level down to 3.5V. The high
voltage compatibility allows EN to be connected to SUP,
KEY/KL30, or the inhibit pin (INH) of a CAN transceiver.
EN turns on the internal regulator. Once VBIAS is above
the internal lockout threshold, VUVL = 3.15V (typ), the
controller activates and the output voltage ramps up
within 8ms.
A logic-low at EN shuts down the device. During
shutdown, the internal linear regulator and gate drivers
turn off. Shutdown is the lowest power state and reduces
the quiescent current to 5FA (typ). Drive EN high to bring
the device out of shutdown.
Spread-Spectrum Option
The devices have an internal spread-spectrum option
to optimize EMI performance. This is factory set and the
S-version of the device should be ordered. For spread-
spectrum-enabled devices, the operating frequency is
varied ±6% centered on the oscillator frequency (fOSC).
The modulation signal is a triangular wave with a period
of 110µs at 2.2MHz. Therefore, fOSC will ramp down 6%
and back to 2.2MHz in 110µs and also ramp up 6% and
back to 2.2MHz in 110µs. The cycle repeats.
For operations at fOSC values other than 2.2MHz, the
modulation signal scales proportionally (e.g., at 400kHz,
the 110µs modulation period increases to 110µs x
2.2MHz/400kHz = 605µs).
The internal spread spectrum is disabled if the device is
synced to an external clock. However, the device does not
filter the input clock and passes any modulation (including
spread-spectrum) present on the driving external clock to
the SYNCOUT pin.
Automatic Slew-Rate Control on LX
The devices have automatic slew-rate adjustment that
optimizes the rise times on the internal HSFET gate drive
to minimize EMI. The device detects the internal clock
frequency and adjusts the slew rate accordingly. When
the user selects the external frequency setting resistor
RFOSC such that the frequency is > 1.1MHz, the HSFET
is turned on in 4ns (typ). When the frequency is < 1.1MHz
the HSFET is turned on in 8ns (typ). This slew-rate control
optimizes the rise time on LX node externally to minimize
EMI while maintaining good efficiency.
Internal Oscillator (FOSC)
The switching frequency (fSW) is set by a resistor (RFOSC)
connected from FOSC to AGND. See Figure 3 to select
the correct RFOSC value for the desired switching fre-
quency. For example, a 400kHz switching frequency is set
with RFOSC = 73.2kI. Higher frequencies allow designs
with lower inductor values and less output capacitance.
Consequently, peak currents and I2R losses are lower
at higher switching frequencies, but core losses, gate
charge currents, and switching losses increase.
Synchronizing Output (SYNCOUT)
SYNCOUT is an open-drain output that outputs a 180N
out-of-phase signal relative to the internal oscillator.
Overtemperature Protection
Thermal-overload protection limits the total power
dissipation in the device. When the junction temperature
exceeds 175NC (typ), an internal thermal sensor shuts
down the internal bias regulator and the step-down
controller, allowing the device to cool. The thermal
sensor turns on the device again after the junction
temperature cools by 15NC.
Figure 2. Adjustable Output-Voltage Setting
RFB2
RFB1
FB
VOUT
MAX16935
MAX16939
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Applications Information
Setting the Output Voltage
Connect FB to BIAS for a fixed 5V output voltage. To
set the output to other voltages between 1V and 10V,
connect a resistive divider from output (OUT) to FB to
AGND (Figure 2). Use the following formula to determine
the RFB2 of the resistive divider network:
RFB2 = RTOTAL x VFB/VOUT
where VFB = 1V, RTOTAL = selected total resistance of
RFB1, RFB2 in ω, and VOUT is the desired output in volts.
Calculate RFB1 (OUT to FB resistor) with the following
equation:
OUT
FB1 FB2 FB
V
RR 1
V


= −





where VFB = 1V (see the Electrical Characteristics table).
FPWM/Skip Modes
The devices offer a pin-selectable skip mode or fixed-
frequency PWM mode option. They have an internal LS
MOSFET that turns on when the FSYNC pin is connected
to VBIAS or if there is a clock present on the FSYNC
pin. This enables the fixed-frequency-forced PWM mode
operation over the entire load range. This option allows the
user to maintain fixed frequency over the entire load range
in applications that require tight control on EMI. Even
though the device has an internal LS MOSFET for fixed-
frequency operation, an external Schottky diode is still
required to support the entire load range. If the FSYNC
pin is connected to GND, the skip mode is enabled on
the device.
In skip mode of operation, the converter’s switching
frequency is load dependent. At higher load current, the
switching frequency does not change and the operating
mode is similar to the FPWM mode. Skip mode helps
improve efficiency in light-load applications by allowing
the converters to turn on the high-side switch only when
the output voltage falls below a set threshold. As such,
the converters do not switch MOSFETs on and off as
often as is the case in the FPWM mode. Consequently,
the gate charge and switching losses are much lower in
skip mode.
Inductor Selection
Three key inductor parameters must be specified for
operation with the devices: inductance value (L), inductor
saturation current (ISAT), and DC resistance (RDCR). To
select inductance value, the ratio of inductor peak-to-
peak AC current to DC average current (LIR) must be
selected first. A good compromise between size and loss
is a 30% peak-to-peak ripple current to average current
ratio (LIR = 0.3). The switching frequency, input voltage,
output voltage, and selected LIR then determine the
inductor value as follows:
OUT SUP OUT
SUP SW OUT
V (V V )
LV f I LIR
−
=
where VSUP, VOUT, and IOUT are typical values (so that
efficiency is optimum for typical conditions). The switch-
ing frequency is set by RFOSC (see Figure 3).
Input Capacitor
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:
OUT SUP OUT
RMS LOAD(MAX) SUP
V (V V )
II V
−
=
IRMS has a maximum value when the input voltage
equals twice the output voltage (VSUP = 2VOUT), so
IRMS(MAX) = ILOAD(MAX)/2.
Choose an input capacitor that exhibits less than +10NC
self-heating temperature rise at the RMS input current for
optimal long-term reliability.
The input voltage ripple is composed of DVQ (caused
by the capacitor discharge) and DVESR (caused by the
ESR of the capacitor). Use low-ESR ceramic capacitors
with high ripple current capability at the input. Assume
Figure 3. Switching Frequency vs. RFOSC
SWITCHING FREQUENCY vs. RFOSC
RFOSC (kΩ)
SWITCHING FREQUENCY (MHz)
1027242
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
0
12 132
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the contribution from the ESR and capacitor discharge
equal to 50%. Calculate the input capacitance and ESR
required for a specified input voltage ripple using the fol-
lowing equations:
ESR
IN L
OUT
V
ESR I
I2
∆
=∆
+
where:
SUP OUT OUT
LSUP SW
(V V ) V
IV fL
−×
∆= ××
and:
OUT OUT
IN Q SW SUPSW
I D(1 D) V
C and D
Vf V
×−
= =
∆×
where IOUT is the maximum output current and D is the
duty cycle.
Output Capacitor
The output filter capacitor must have low enough ESR
to meet output ripple and load transient requirements.
The output capacitance must be high enough to absorb
the inductor energy while transitioning from full-load
to no-load conditions without tripping the overvoltage
fault protection. When using high-capacitance, low-ESR
capacitors, the filter capacitor’s ESR dominates the
output voltage ripple. So the size of the output capaci-
tor depends on the maximum ESR required to meet the
output voltage ripple (VRIPPLE(P-P)) specifications:
RIPPLE(P P ) LOAD( MAX )
V ESR I LIR
−
=××
The actual capacitance value required relates to the
physical size needed to achieve low ESR, as well as
to the chemistry of the capacitor technology. Thus, the
capacitor is usually selected by ESR and voltage rating
rather than by capacitance value.
When using low-capacity filter capacitors, such as
ceramic capacitors, size is usually determined by
the capacity needed to prevent voltage droop and
voltage rise from causing problems during load
transients. Generally, once enough capacitance is added
to meet the overshoot requirement, undershoot at the
rising load edge is no longer a problem. However, low
capacity filter capacitors typically have high ESR zeros
that can affect the overall stability.
Rectier Selection
The devices require an external Schottky diode rectifier
as a freewheeling diode when they are configured for
skip-mode operation. Connect this rectifier close to the
device, using short leads and short PCB traces. In FPWM
mode, the Schottky diode helps minimize efficiency
losses by diverting the inductor current that would other-
wise flow through the low-side MOSFET. Choose a rectifier
with a voltage rating greater than the maximum expected
input voltage, VSUPSW. Use a low forward-voltage-drop
Schottky rectifier to limit the negative voltage at LX. Avoid
higher than necessary reverse-voltage Schottky rectifiers
that have higher forward-voltage drops.
Compensation Network
The devices use an internal transconductance error ampli-
fier with its inverting input and its output available to the
user for external frequency compensation. The output
capacitor and compensation network determine the loop
stability. The inductor and the output capacitor are chosen
based on performance, size, and cost. Additionally, the
compensation network optimizes the control-loop stability.
The controller uses a current-mode control scheme that
regulates the output voltage by forcing the required
current through the external inductor. The device uses
the voltage drop across the high-side MOSFET to sense
inductor current. Current-mode control eliminates the
double pole in the feedback loop caused by the inductor
and output capacitor, resulting in a smaller phase shift
and requiring less elaborate error-amplifier compensation
than voltage-mode control. Only a simple single-series
resistor (RC) and capacitor (CC) are required to have a
stable, high-bandwidth loop in applications where ceramic
capacitors are used for output filtering (Figure 4). For other
types of capacitors, due to the higher capacitance and
ESR, the frequency of the zero created by the capacitance
and ESR is lower than the desired closed-loop crossover
frequency. To stabilize a nonceramic output capacitor
loop, add another compensation capacitor (CF) from
COMP to GND to cancel this ESR zero.
Figure 4. Compensation Network
R2
R1
VREF
VOUT
RC
CC
CF
COMP
gm
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The basic regulator loop is modeled as a power
modulator, output feedback divider, and an error
amplifier. The power modulator has a DC gain set by
gm O RLOAD, with a pole and zero pair set by RLOAD,
the output capacitor (COUT), and its ESR. The following
equations allow to approximate the value for the gain
of the power modulator (GAINMOD(dc)), neglecting the
effect of the ramp stabilization. Ramp stabilization is
necessary when the duty cycle is above 50% and is
internally done for the device.
MOD(dc) m LOAD
GAIN g R= ×
where RLOAD = VOUT/ILOUT(MAX) in I and gm = 3S.
In a current-mode step-down converter, the output
capacitor, its ESR, and the load resistance introduce a
pole at the following frequency:
=π× ×
pMOD OUT LOAD
1
f2C R
The output capacitor and its ESR also introduce a zero at:
zMOD OUT
1
f2 ESR C
=π× ×
When COUT is composed of “n” identical capacitors
in parallel, the resulting COUT = n O COUT(EACH), and
ESR = ESR(EACH)/n. Note that the capacitor zero for a
parallel combination of alike capacitors is the same as for
an individual capacitor.
The feedback voltage-divider has a gain of GAINFB = VFB/
VOUT, where VFB is 1V (typ). The transconductance error
amplifier has a DC gain of GAINEA(dc) = gm,EA O ROUT,EA,
where gm,EA is the error amplifier transconductance,
which is 700FS (typ), and ROUT,EA is the output
resistance of the error amplifier 50MI.
A dominant pole (fdpEA) is set by the compensation
capacitor (CC) and the amplifier output resistance
(ROUT,EA). A zero (fzEA) is set by the compensation
resistor (RC) and the compensation capacitor (CC).
There is an optional pole (fpEA) set by CF and RC to
cancel the output capacitor ESR zero if it occurs near
the crossover frequency (fC), where the loop gain equals
1 (0dB)). Thus:
dpEA C O U T ,E A C
zEA CC
pEA FC
1
f2 C (R R )
1
f2C R
1
f2CR
=π× × +
=π× ×
=π× ×
The loop-gain crossover frequency (fC) should be set
below 1/5th of the switching frequency and much higher
than the power-modulator pole (fpMOD):
SW
pMOD C
f
ff
5
<< ≤
The total loop gain as the product of the modulator gain,
the feedback voltage-divider gain, and the error amplifier
gain at fC should be equal to 1. So:
FB
MOD(fC) EA(fC)
OUT
V
GAIN GAIN 1
V
×× =
EA(fC) m, EA C
pMOD
MOD(fC) MOD(dc) C
GAIN g R
f
GAIN GAIN f
= ×
= ×
Therefore:
FB
MOD(fC) m,EA C
OUT
V
GAIN g R 1
V
× × ×=
Solving for RC:
OUT
Cm,EA FB MOD(fC)
V
Rg V GAIN
=××
Set the error-amplifier compensation zero formed by RC
and CC (fzEA) at the fpMOD. Calculate the value of CC a
follows:
CpMOD C
1
C2f R
=π× ×
If fzMOD is less than 5 x fC, add a second capacitor,
CF, from COMP to GND and set the compensation pole
formed by RC and CF (fpEA) at the fzMOD. Calculate the
value of CF as follows:
FzMOD C
1
C2f R
=π× ×
As the load current decreases, the modulator pole
also decreases; however, the modulator gain increases
accordingly and the crossover frequency remains the
same.
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PCB Layout Guidelines
Careful PCB layout is critical to achieve low switching
losses and clean, stable operation. Use a multilayer board
whenever possible for better noise immunity and power
dissipation. Follow these guidelines for good PCB layout:
1) Use a large contiguous copper plane under the IC
package. Ensure that all heat-dissipating compo-
nents have adequate cooling. The bottom pad of the
IC must be soldered down to this copper plane for
effective heat dissipation and for getting the full power
out of the IC. Use multiple vias or a single large via in
this plane for heat dissipation.
2) Isolate the power components and high current path
from the sensitive analog circuitry. Doing so is essential
to prevent any noise coupling into the analog signals.
3) Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable,
jitter-free operation. The high-current path composed
of the input capacitor, high-side FET, inductor, and
the output capacitor should be as short as possible.
4) Keep the power traces and load connections short. This
practice is essential for high efficiency. Use thick copper
PCBs (2oz vs. 1oz) to enhance full-load efficiency.
5) The analog signal lines should be routed away from
the high-frequency planes. Doing so ensures integrity
of sensitive signals feeding back into the IC.
6) The ground connection for the analog and power
section should be close to the IC. This keeps the
ground current loops to a minimum. In cases where
only one ground is used, enough isolation between
analog return signals and high power signals must be
maintained.
D1 COUT
22µF
CIN2
RCOMP
20kIRPGOOD
10kI
RSYNCOUT
100I
RFOSC
12kI
L1
2.2µH VOUT
5V AT 3.5A
CBST
0.22µF
LX
BST
VOUT VBIAS
OUT
VBAT
FB
VBIAS
VOUT
PGOOD
SYNCOUT
FOSC
CBIAS
1µF
CCOMP2
12pF
BIAS
CCOMP1
1000pF
COMP
FSYNC
OSC SYNC PULSE
EN
SUPSWSUP
CIN1
POWER-GOOD OUTPUT
180° OUT-OF-PHASE OUTPUT
AGNDPGND
MAX16935
MAX16939
RSNUB*
CSNUB*
*RFILTER = 1I and CFILTER = 220pF required for the following
operating conditions:
VBAT R 25V, VOUT P 5V, fSW R 1.8MHz, FPWM mode enabled
Typical Application Circuit
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/V denotes an automotive qualified part.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future product—contact factory for availability.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
16 TQFN-EP T1655+4 21-0140 90-0121
16 TSSOP-EP U16E+3 21-0108 90-0120
PART
VOUT
SPREAD
SPECTRUM TEMP RANGE PIN-
PACKAGE
ADJUSTABLE
(FB CONNECTED TO
RESISTIVE DIVIDER) (V)
FIXED
(FB CONNECTED
TO BIAS) (V)
MAX16935BAUER/V+ 1 to 10 5Off -40°C to +125°C 16 TSSOP-EP*
MAX16935BAUES/V+ 1 to 10 5 On -40°C to +125°C 16 TSSOP-EP*
MAX16935CAUER/V+ 1 to 10 5Off -40°C to +125°C 16 TSSOP-EP*
MAX16935CAUES/V+ 1 to 10 5 On -40°C to +125°C 16 TSSOP-EP*
MAX16935CAUERB/V+ 1 to 10 3.3 Off -40°C to +125°C 16 TSSOP-EP*
MAX16935CAUESB/V+ 1 to 10 3.3 On -40°C to +125°C 16 TSSOP-EP*
MAX16935RATE/V+ 1 to 10 5Off -40°C to +125°C 16 TQFN-EP*
MAX16935RATEB/V+ 1 to 10 3.3 Off -40°C to +125°C 16 TQFN-EP*
MAX16935RAUE/V+ 1 to 10 5Off -40°C to +125°C 16 TSSOP-EP*
MAX16935RAUEB/V+ 1 to 10 3.3 Off -40°C to +125°C 16 TSSOP-EP*
MAX16935SATE/V+ 1 to 10 5 On -40°C to +125°C 16 TQFN-EP*
MAX16935SATEB/V+ 1 to 10 3.3 On -40°C to +125°C 16 TQFN-EP*
MAX16935SAUE/V+ 1 to 10 5 On -40°C to +125°C 16 TSSOP-EP*
MAX16935SAUEB/V+ 1 to 10 3.3 On -40°C to +125°C 16 TSSOP-EP*
MAX16939ATERA/V+ 1 to 10 5Off -40°C to +125°C 16 TQFN-EP*
MAX16939ATERB/V+ 1 to 10 3.3 Off -40°C to +125°C 16 TQFN-EP*
MAX16939AUERA/V+** 1 to 10 5Off -40°C to +125°C 16 TSSOP-EP*
MAX16939AUERB/V+** 1 to 10 3.3 Off -40°C to +125°C 16 TSSOP-EP*
MAX16939ATESA/V+ 1 to 10 5 On -40°C to +125°C 16 TQFN-EP*
MAX16939ATESB/V+ 1 to 10 3.3 On -40°C to +125°C 16 TQFN-EP*
MAX16939AUESA/V+** 1 to 10 5 On -40°C to +125°C 16 TSSOP-EP*
MAX16939AUESB/V+** 1 to 10 3.3 On -40°C to +125°C 16 TSSOP-EP*
Ordering Information/Selector Guide
Package Information
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.
Chip Information
PROCESS: BiCMOS
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REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 12/13 Initial release —
1 2/14 Corrected typo for gm value in Compensation Network section 13
2 3/14 Updated PGOOD pin description and updated Spread Spectrum, Automatic Slew-
Rate Control on LX, and Internal Oscillator (FOSC) sections 9, 11
3 1/15
Added TQFN options to General Description, Absolute Maximum Ratings, Package
Thermal Characteristics, Pin Configurations, Pin Description, Package Information,
and Ordering Information
1, 2, 8, 9, 18
4 2/15 Updated the Benefits and Features section
5 3/15 Corrected the first equation on the top left side of page 14
6 5/15
Added 3.3V output-voltage option; updated General Description, Absolute Maximum
Ratings, Package Thermal Characteristics, Electrical Characteristics, and Detailed
Description sections, deleted graph 16 and replaced graphs 01–06, 14, 15, 21 in
Typical Operating Characteristics; added four new /V OPNs to Ordering Information/
Selector Guide
1–7, 9, 16
7 5/15 Removed future product designations in Ordering Information 16
8 6/15 Added the MAX16939 to the data sheet as a future product 1–17
9 6/15 Corrected MAX16939 variants in Ordering Information/Selector Guide 16
10 4/16 Added bullet to Benefits and Features section, removed future product references 1, 16
11 8/16 Added PGOOD Assertion Delay in Electrical Characteristics, and added new
MAX16935 variants in Ordering Information/Selector Guide 4, 16
12 4/17 Removed future product status from MAX16935BAUES/V+/MAX16935BAUER/V+ in
Ordering Information/Selector Guide 16
13 5/17
Added Supply Current and PGOOD Switching Level for MAX16935C in Electrical
Characteristics, and added new MAX16935C future product variants in Ordering
Information/Selector Guide
2, 4, 16
14 6/17
Added new row in PGOOD Switching Level for MAX16935C in Electrical
Characteristics, updated Overvoltage Protection (OVP) section, and changed seven
variants in Ordering Information/Selector Guide from TSSOP-EP to TQFN-EP
4, 10, 16
15 7/17
Removed future product status from MAX16935CAUER/V+, MAX16935CAUES/
V+; added MAX16935CAUERB/V+, MAX16935CAUESB/V+ as future products in
Ordering Information/Selector Guide
16
16 10/17 Removed future product status from MAX16935CAUERB/V+, MAX16935CAUESB/
V+ in Ordering Information/Selector Guide 16
16.1 Added back future product status on MAX16935CAUERB/V+, MAX16935CAUESB/
V+ in Ordering Information/Selector Guide 16
17 1/18 Removed future product status from MAX16935CAUERB/V+, MAX16935CAUESB/
V+ in Ordering Information/Selector Guide 16
Revision History
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 specications 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.
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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.