FREI MAX17620ATA+T Datasheet

LX

V

OUT

FB

GND

MODE

IN

PGOOD

EN

2.7V TO 5.5V

R1
24kΩ

V

OUT

1.8V/600mA

C

IN

2.2µF

L

1µH

MAX17620

CIN: 2.2µF/10V/0603/X7R,

GRM188R71A225KE15D, MUR

ATA

L1: 1μH, 60mΩ, MAKK2016H1ROM, TAIYO-YUDEN
C

OUT

: 10μF/6.3V/0805/X7R, GRM21BR70J106KE76K, MURATA

C

OUT

10µF

R2

19.1kΩ

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

General Description

The MAX17620 is a high-frequency, high-efficiency
synchronous step-down DC-DC converter with integrated
MOSFETs that operates over a 2.7V to 5.5V input voltage
range. The device supports up to 600mA load current and

1.5V to 100% VIN output voltage. High-frequency operation
enables the use of small, low-cost inductors and capacitors.

The device features selectable PWM/skip mode of
operation at light loads and operates at a 4MHz fixed­frequency in PWM mode. Skip mode improves system
efficiency at light loads, while PWM mode maintains a
constant switching frequency over the entire load.
In skip mode, the device draws only 40µA of quiescent
current from the supply input. In shutdown mode, the current
consumption is reduced to 0.1µA.

The device also features a soft-start feature to reduce
the inrush current during startup, and also incorporates an
enable (EN) pin to turn on/off the device. An open-drain
PGOOD pin provides power-good signal to the system
upon achieving successful regulation of the output voltage.

The MAX17620 is available in an 8-pin, 2mm x 2mm
TDFN package and operates over the -40°C to +125°C
temperature range.

Applications

● Point-of-Load Power Supply

● Standard 5V Rail Supplies

● Battery-Powered Instruments

● Distributed Power Systems

Benets and Features

● Minimizes External Components, Reducing Total

Cost

• Synchronous Operation for High Efciency and

Reduced Cost

• Internal Compensation for Stable Operation at Any
Output Voltage

• All-Ceramic Capacitor Solution

• 4MHz Operation

• Only 5 External Components Required

• Total Solution Size is 12mm2 (Sum of the
Components Area)

● Reduces Number of DC-DC Regulators to Stock

• Wide 2.7V to 5.5V Input Voltage Range

• Adjustable 1.5V to 100% VIN Output Voltage Range

• Delivers Up to 600mA Load Current

• 100% Duty-Cycle Operation

• +1%/-0.75% Reference Voltage Accuracy

• Available in a 2mm x 2mm TDFN Package

● Reduces Power Dissipation

• Peak Efciency 91%

• Skip Mode for High Light-Load Efciency

• Shutdown Current = 0.1µA

● Operates Reliably

• Peak Current-Limit Protection

• Soft-Start Reduces Inrush Current During Startup

• Built-In Output-Voltage Monitoring
(Open-Drain PGOOD Pin)

• -40°C to +125°C Operation

Ordering Information appears at end of data sheet.

Typical Application Circuit—1.8V, 600mA Step-Down Regulator

19-7543; Rev 3; 7/16

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Absolute Maximum Ratings

IN to GND ..................................................................-0.3V to 6V

LX to GND .................................................................-0.3V to 6V

MODE .......................................................... -0.3V to VIN + 0.3V

EN, PGOOD, FB, V

to GND .............................. -0.3V to 6V

OUT

Continuous Power Dissipation (up to TA = +70°C)

(derate 9.8mW/°C above TA = +70°C) .........................784.3mW

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.

Operating Temperature Range ......................... -40°C to +125°C

Junction Temperature ......................................................+150°C

Storage Temperature Range ............................ -65°C to +150°C

Soldering Temperature (Reflow) ...................................... +260°C

Package Thermal Characteristics

(Note 1)

TDFN

Junction-to-Ambient Thermal Resistance (θJA) ........102°C/W Junction-to-Case Thermal Resistance (θJC) .................8°C/W

Note 1: 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

VIN = +3.6V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical specifications are at TA = TJ = +25°C. (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

INPUT SUPPLY (IN)

Input Voltage Range V

I

IN-SH

Input Supply Current

Undervoltage-Lockout Threshold
(UVLO)

UVLO Hysteresis V

I

Q_SKIP

I

Q-PWM

V

IN_UVLO

IN_UVLO_HYS

ENABLE (EN)

EN Low Threshold V

EN High Threshold V

EN Hysteresis V

EN_LOW

EN_HIGH

EN_HYS

EN Input Leakage I

POWER MOSFETS

High-Side pMOS On-Resistance R

High-Side pMOS On-Resistance R

Low-Side nMOS On-Resistance R

Low-Side nMOS On-Resistance R

LX Leakage Current I

High-Side Peak Current Limit I

Low-Side Valley Current Limit I

Low-Side Negative Current Limit I

Low-Side Zero-Crossing
Current Limit

DS-ONH

DS-ONH

DS-ONL

DS-ONL

LX_LKG

LIM_PEAK

LIM_VALLEY

LIM_NEG

I

LIM_ZX

EN

IN

VEN = 0V, shutdown mode 0.1

Nonswitching 40

PWM mode (switching) 6 mA

VIN rising 2.55 2.6 2.65 V

VEN falling 0.8 V

VEN rising 2 V

VEN = 5.5V, TA = TJ = +25°C 10 50 nA

VIN = 3.6V, ILX = 190mA 120 200 mΩ

VIN = 5.0V, ILX = 190mA 100 160 mΩ

VIN = 3.6V, I

= 190mA 80 145 mΩ

LX

VIN = 5.0V, ILX = 190mA 70 130 mΩ

LX = GND or IN, TA = +25°C 0.1 1 µA

Current entering into LX pin 1050 mA

MODE = IN, current leaving out of LX
pin

2.7 5.5 V

µA

200 mV

220 mV

1150 1450 1800 mA

920 1170 1450 mA

100 mA

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Electrical Characteristics (continued)

VIN = +3.6V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical specifications are at TA = TJ = +25°C. (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SWITCHING FREQUENCY

Switching Frequency f

Minimum Controllable On-Time t

LX Dead Time 3 ns

Soft-Start Time t

FEEDBACK (FB)

FB Voltage Accuracy V

FB Input Bias Current I

POWER GOOD (PGOOD)

PGOOD Rising Threshold FB rising 91.5 93.5 95.5 %

PGOOD Falling Threshold FB falling 88 90 92 %

PGOOD Output Low I

PGOOD Output Leakage Current I

MODE

MODE Pullup Current V

THERMAL SHUTDOWN

Thermal-Shutdown Rising
Threshold

Thermal-Shutdown Hysteresis 10 °C

Note 2: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range and relevant supply voltage

range are guaranteed by design and characterization.

SW

ON_MIN

SS

FB

FB

PGOOD_LKG

MODE = GND 3.84 4 4.16 MHz

40 ns

tSS = 4096 CLK cycles 1 ms

PWM mode -0.75 +1 %

FB = 0.6V, TA = TJ = 25°C 50 120 nA

= 5mA 200 mV

PGOOD

PGOOD = 5.5V, TA = TJ = 25°C 100 nA

= GND 5 µA

MODE

Temperature rising 165 °C

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3

60

65

70

75

80

85

90

95

100

50 150 250 350 450 550

EFFICIENCY (%)

LOAD CURR ENT (mA)

1.8V OUTPUT, PWM MODE,

EFFICIENCY vs. LOAD CURRENT

VIN= 5.5V

VIN= 4.2V

VIN= 3.6V

VIN= 2.7V

MODE = GND

1.790

1.795

1.800

1.805

1.810

1.815

1.820

1.825

1.830

0 100 200 300 400 500 600

OUTPUT VOLTAGE

(V)

LOAD CURR ENT (mA)

1.8V OUTPUT, SKIP MODE,

LOAD AND LINE REGULATION

VIN= 3.6V

VIN= 2.7V

VIN= 5.5V

VIN= 4.2V

MODE = OPEN

EFFICIENCY vs. LOAD CURRENT

600

OUTPUT VOLTAGE

(V)

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Typical Operating Characteristics

(See the Typical Application Circuits, TA = +25°C, VIN = 3.6V, unless otherwise noted.)

1.8V OUTPUT, SKIP MODE,

100

95

90

85

EFFICIENCY (%)

80

75

70

810

808

806

804

802

800

798

796

FEEDBACK VOLTAGE (V)

794

792

790

-40 -20 0 20 40 60 80 100 120

VIN= 2.7V

1 10 100

LOAD CURR ENT (mA)

FEEDBACK VOLTAGE vs. TEMPERATURE

TEMPERATURE (°C)

VIN= 3.6V

VIN= 4.2V

MODE = OPEN

VIN= 5.5V

1.8V OUTPUT, PWM MODE,

1.810

1.805

1.800

1.795

1.790

INPUT SUPPLY CURRENT (µA)

LOAD AND LINE REGULATION

VIN= 3.6V

VIN= 2.7V

0 100 200 300 400 500 600

INPUT SUPPLY CURRENT vs.

60

55

50

45

40

35

30

TEMPERATURE, SKIP MODE

V

= 3.6V

IN

-40 -20 0 20 40 60 80 1 00 120

TEMPERATURE (°C)

VIN= 4.2V

MODE = GND

LOAD CURR ENT (mA)

VIN= 5.5V

VIN= 2.7V

VIN= 5.5V

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SHUTDOWN CURRENT vs. TEMPERATURE

70

60

50

40

30

20

10

SHUTDOWN CURRENT (nA)

0

-10

-40 -2 0 0 20 40 60 80 100 120

VIN= 5.5V

VIN= 3.6V

VIN= 2.7V

TEMPERATURE (°C)

SOFT-START FROM EN, PWM MODE,

1.8V OUTPUT, NO LOAD CURRENT

V

EN

V

OUT

V

PGOOD

I

OUT

200μs/div

5V/div

1V/div

2V/div

200mA/div

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Typical Operating Characteristics (continued)

(See the Typical Application Circuits, TA = +25°C, VIN = 3.6V, unless otherwise noted.)

SOFT-START/SHUTDOWN FROM EN,

1.8V OUTPUT, 600mA LOAD CURRENT

V

EN

V

OUT

I

IN

V

PGOOD

1ms/div

STEADY-STATE SWITCHING WAVEFORMS,

1.8V OUTPUT, 600mA LOAD CURRENT

V

OUT

(AC)

V

X

L

I

LX

100ns/div

5V/div

1V/div

200mA/div

2V/div

10mV/div

2V/div

500mA/div

SOFT-START WITH 1V PREBIAS,

1.8V OUTPUT, PWM MODE

V

EN

V

OUT

V

PGOOD

200μs/div

STEADY-STATE SWITCHING WAVEFORMS,

1.8V OUTPUT, 10mA LOAD, SKIP MODE

V

OUT

(AC)

V

LX

I

LX

4µs/div

5V/div

1V/div

2V/div

20mV/div

2V/div

500mA/div

STEADY-STATE SWITCHING WAVEFORMS,

1.8V OUTPUT, NO LOAD, PWM MODE

V

OUT

(AC)

V

X

L

I

LX

100ns/div

1.8V OUTPUT, PWM MODE,
(LOAD CURRENT STEPPED
FROM NO LOAD TO 300mA)

V

OUT

(AC)

I

OUT

40μs/div

10mV/div

2V/div

200mA/div

20mV/div

200mA/div

(LOAD CURRENT STEPPED

V

OUT

(AC)

I

OUT

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1.8V OUTPUT,

FROM 300mA TO 600mA)

40μs/div

20mV/div

200mA/div

V

(AC)

I

1.8V OUTPUT, SKIP MODE,
(LOAD CURRENT STEPPED

FROM 5mA TO 300mA)

OUT

OUT

40µs/div

50mV/div

200mA/div

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Typical Operating Characteristics (continued)

(See the Typical Application Circuits, TA = +25°C, VIN = 3.6V, unless otherwise noted.)

1.8V OUTPUT, SKIP MODE,

(LOAD CURRENT STEPPED

FROM 5mA TO 50mA)

OVERLOAD PROTECTION, 1.8V OUTPUT

V

(AC)

I

TOC19

V

OUT

I

OUT

400µs/div

OUT

OUT

40µs/div

20mV/div

50mA/div

BODE PLOT

1V/div

500mA/div

GAIN

PHASE

GAIN (dB)

PHASE (º)

FCR= 189KHz,
PHASE MARGIN = 62°

FREQUENCY(Hz)

GAIN

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6

+

MAX17620

IN

TDFN

(2mm x 2mm)

TOP VIEW

LX

8

7 6 5

432

1

V

OUT

FB

PGOOD

GND EN MODE

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Pin Conguration

Pin Description

PIN NAME FUNCTION

1 IN

Power Supply Input. Connect a minimum 1µF ceramic capacitor from IN to GND for bypassing high­frequency noise on IN pin to ground.

2 GND Ground Pin. Connect to system ground.

3 EN

4 MODE

Enable Input. Logic-high voltage on EN pin enables the device, while logic-low voltage disables the
device.

PWM or Skip Mode Selection Input. Connect the MODE pin to GND to enable PWM mode operation.
Leave the MODE pin unconnected to enable skip mode operation.

Open-Drain Power Good Output. Connect PGOOD pin to output voltage or IN pin through an external

5 PGOOD

pullup resistor to generate a “high” level if the output voltage is above 93% of the target regulated

voltage. If not used, leave this pin unconnected. The PGOOD is driven low if the output voltage is below

90% of the target regulated voltage.

6 FB

7 V

OUT

Feedback Input. Connect FB to the center of the external resistor-divider from output to GND to set the
output voltage.

Output Voltage Input. Connect the positive terminal of the output voltage to the V

8 LX Switching Node. Connect LX pin to the switching node of the inductor.

— EP Exposed Pad. Connect exposed pad to the system ground.

OUT

pin.

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HIGH-SIDE

CURRENT SENSE

LOGIC

HSCS

LOW SIDE

CURRENT SENSE

LOGIC

DRIVER

LOGIC

GND

LX

BANDGAP

HSLIM

IPFM

LSLIM

ZX

CONTROL

LOGIC

IN

EN

PGOOD

SOFT

START

CLK

FB

PWM

VREF

SLOPE

HSCS

+

+

MAX17620

FB

0.748V

2V

UVLO

THERMAL

SHUTDOWN

CHIPEN

OSCILLATOR

CLK

0.55 x V

IN

MODE

IN

PFM_EN

VOUT

POK

THSD

VREF

SKIP

PFM_EN

5µA

LSCS

ERROR

AMPLIFIER

SLOPE

COMPENSATION

PWMSKIP

CHIPEN

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Block Diagram

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Detailed Description

The MAX17620 is a high-frequency, high-efficiency
synchronous step-down DC-DC converter with integrated
MOSFETs that operates over a 2.7V to 5.5V input voltage
range. The device supports up to 600mA load current
and 1.5V to 100% VIN output voltage. High-frequency
operation allows the use of small, low-cost inductors and
capacitors.

The device features a MODE pin to set the device to operate in
PWM or skip mode under light-load conditions. In PWM Mode, the
device operates with its nominal switching frequency of 4MHz
over entire load current range. In skip mode, the device skips
some cycles at light loads thereby reducing the switching
frequency and achieving high efficiency. The device
features a soft-start, open-drain power-good signal
(PGOOD) and enable input (EN).

Control Architecture

The device uses an internally compensated, peak­current-mode-control architecture. The high-side MOSFET
is turned on at each clock edge and the low-side MOSFET
is turned off. The high-side MOSFET remains on until the
sum of the high-side MOSFET current-sense voltage and
the internal slope compensating ramp voltage hits the
control voltage generated by the error amplifier. At this
moment, the high-side MOSFET is turned off and the low­side MOSFET is turned on.

During the high-side MOSFET on-time, the inductor
current ramps up and stores energy. During the low-side
MOSFET on-time, the inductor current ramps down and
releases the stored energy to the output.

Enable Input (EN)

The device is enabled by setting the EN pin to a logic­high. Accordingly, a logic-low disables the device. When
the device is enabled, an internal soft-start circuitry
monotonically ramps up the error amplifier’s reference
voltage from 0 to 0.8V in fixed soft-start time of 1ms. This
causes the output voltage to ramp monotonically from 0V
to set voltage. It also avoids excessive inrush current and
prevents excessive voltage drop of batteries with high
internal impedance.

Driving EN low disables the switching and output is

discharged with a typical discharge resistor of 225Ω. The

same happens when the device gets disabled by thermal
shutdown or undervoltage-lockout trigger.

Mode Selection (MODE)

The device can be set to operate in either PWM mode
or skip mode under light-load conditions by connecting
the MODE pin to ground or leaving it unconnected.
Connecting the MODE pin to ground sets the device to
PWM mode and leaving it unconnected sets the device
to skip mode.

In PWM mode, the device operates with its nominal
switching frequency of 4MHz over the entire load current
range and the inductor current is allowed to go negative.
PWM mode is useful in applications where constant
switching frequency is desired.

In skip mode, the device skips pulses at light loads for
high efficiency and the inductor current is not allowed to
go negative. In this mode, when the output voltage falls
below the target value, the internal high-side MOSFET
is turned on until the inductor current reaches to peak
current threshold in skip mode. Once the high-side FET is
turned off, the low-side FET is turned on until the inductor
current falls to zero. The device enters into PWM mode if
the output voltage is below the target voltage during the
next 3 clock cycles after the inductor current falls to zero. If
the output voltage is above the target value during the next
3 clock cycles, then both the high-side and low-side FETs
are turned off and the device enters hibernation mode until
the load discharges the output below the target value.

The peak current threshold in skip mode is a function
of the output inductor and is (375/L)mA, where L is the
output inductor value in µH. The advantage of the skip
mode is higher efficiency at light loads because of lower
quiescent current drawn from the supply. The disadvantage
is that the output-voltage ripple is higher compared
to that of the PWM mode operation and the switching
frequency is not constant at light loads. The device
always operates in skip mode during soft-start under light
loads independent of the MODE pin status. The peak
current threshold in skip mode during soft-start is reduced
to 50% of the value during steady-state operation.

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Power-Good Indicator (PGOOD)

The device includes an open-drain power good output
that indicates the output voltage status. PGOOD goes

high impedance when the output voltage is above 93.5%

of the target value, and goes low when the output voltage

is below 90% of the target value.

Startup Into a Prebiased Output

The device is capable of soft-starting into a prebiased
output without discharging the output. The device
ramps up the output voltage monotonically from the
prebiased level to the target level during the soft-start
period if the prebiased voltage is less than the target
output voltage. If the prebiased voltage is more than the
target output voltage, no switching happens during the
soft-start period. The device operation after the completion
of the soft-start period under prebiased output condition
(where the prebiased voltage is higher than the target
output voltage) depends on the PWM/skip mode. In PWM
Mode, the device tries to regulate the output voltage to the
target level by sinking current from the prebiased source.
In skip mode, the device does not initiate switching until
the output voltage falls below the target output voltage.

100% Duty-Cycle Operation

The device can provide 100% duty-cycle operation. In
this mode, the high-side switch is constantly turned on,
while the low-side switch is turned off. This is particularly
useful in battery-powered applications to achieve longest
operation time by taking full advantage of the whole
battery-voltage range. The minimum input voltage to
maintain the output-voltage regulation can be calculated
as:

Undervoltage Lockout

The device features an integrated input undervoltage
lockout (UVLO) feature that turns the device on/off based
on the voltage at the IN pin. The device turns on if the IN
pin voltage is higher than the UVLO threshold (V
of 2.6V (typ) (assuming EN is at logic-high) and turns off
when the IN pin voltage is 200mV (V
the V

IN_UVLO

.

IN_UVLO_HYS

IN_UVLO

)

) below

Overcurrent Protection

The device features a robust overcurrent-protection
scheme that protects the device and inductor under
overload and output short-circuit conditions. A cycle-by­cycle peak current limit turns off the high-side MOSFET
and turns on the low-side MOSFET whenever the high­side MOSFET current exceeds the internal peak current
limit of 1.45A (typ). The low-side MOSFET remains on
until the next clock cycle. The high-side MOSFET is
turned on again, if the inductor current is less than the
valley current limit at the next clock rising edge. Otherwise,
the low-side MOSFET is kept on for the next clock cycle
as well. Under severe overload conditions, the current will
not exceed 1.45A. If the overload condition is removed,
the part recovers smoothly to target output voltage with no
overshoot.

Thermal Shutdown

Thermal-shutdown protection limits the total power
dissipation in the device. When the device junction
temperature exceeds +165°C, an on-chip thermal
sensor shuts down the device, allowing it to cool. The
thermal sensor turns the device on again after the junction
temperature cools by 10°C.

V

where,

V

V

I

OUT

RON is the sum of the high-side FET on-resistance and
the output inductor DCR

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is the minimum input voltage

IN_MIN

is the target output voltage

OUT

is the load current

IN_MIN

= V

OUT

+ (I

OUT

x RON)

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Applications information

Inductor Selection

Three key inductor parameters must be specified to select
output inductor:

1) Inductor value

2) Inductor saturation current

3) DC resistance of the Inductor

The device’s internal slope compensation and current
limit are optimized for 1µH output inductor. Select 1µH
inductor with a saturation current rating higher than the

maximum peak current limit of 1.9A. Inductor with low

DC resistance improves the efficiency of the system.
Selecting ferrite-cored inductors reduces the core losses
and improves efficiency. Table 1 lists recommended
inductors for use in designs.

Table 1. List of Recommended Inductors

INDUCTANCE

(µH)

1 2.6 37 2.5 x 2 x 1.2 IFSC1008ABER1R0M01 Vishay Dale

1 3.2 50 2.5 x 2 x 1 252010CDMCDS-1R0MC Sumida

1 2.3 48 2.5 x 2 x 0.9 CIG22E1R0MNE

1 2.3 48 2.5 x 2 x 1.2 MLP2520K1R0MT0S1 TDK Corporation

1 2.7 60 2 x 1.6 x 1 MAKK2016H1ROM Taiyo Yuden

CURRENT

RATING

(A)

DC RESISTANCE

(TYP)

(mΩ)

DIMENSIONS

Output Capacitor Selection

X7R ceramic capacitors are preferred as output capaci­tors due to their stability over temperature in industrial
applications. The device’s internal loop-compensation
parameters are optimized for 10µF output capacitors. The
device requires a minimum of 10µF (typ) capacitance for
stability. Table 2 lists the recommended output capacitors.
Capacitors rated less than 4V can be selected for output
voltages less than 3V.

L x W x H

(mm3)

PART NUMBER MANUFACTURER

Samsung

Electro-Mechanics

America

Table 2. List of Recommended Output Capacitors

CAPACITANCE

(µF)

10 X7R 6.3 0805 C2012X7R0J106K125AB TDK Corporation

10 X7R 6.3 0805 GRM21BR70J106KE76K Murata Americas

10 X7R 6.3 0805 JMK212B7106KG-T Taiyo Yuden

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DIELECTRIC

TYPE

VOLTAGE RATING

(V)

PACKAGE

PART

NUMBER

MANUFACTURER

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11

R1

R2

MAX17620

FB

V

OUT

GND

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Input Capacitor Selection

The input filter capacitor reduces peak current 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 (I
equation:

II

RMS_CIN OUT(MAX)

=

where:

I

OUT(MAX)

V

IN

V

OUT

is the maximum load current

is the input voltage

is the output voltage

Use low-ESR ceramic capacitors as the input capaci­tor. X7R temperature coefficient capacitors are recom­mended in industrial applications for their stability over
temperature. Calculate the input capacitor value using the
following equation:

OUT(MAX) OUT IN OUT

C

=

IN

where:

f

is the switching frequency (= 4MHz)

SW

η is the efficiency

In applications where the input source is located distant
from the device input, an 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 cable and the ceramic
capacitor.

) is defined by the following

RMS

x( )

V VV

OUT IN OUT

x

x x( )I V VV

f VVxx xη

∆

SW IN I2N

−

V

IN

−

particular operating condition, the power losses that lead
to the temperature rise of the device are estimated as
follows:

P P IRx1 x

LOSS OUT OUT DCR



= −−






1



η



2

(

)

where,

P

is the output power given by the following equation:

OUT

P

OUT = VOUT

x I

OUT

See the Typical Operating Characteristics for the power-
conversion efficiency or measure the efficiency to deter­mine the total power losses.

The junction temperature (TJ) of the device can be
estimated at any ambient temperature (TA) from the
following equation:

T

J = TA

+ (θJA x P

LOSS

)

where θJA is the junction-to-ambient thermal resistance
of the package (102°C/W for a four-layer board measured
using JEDEC specification JESD51-7).

If the application has a thermal-management system that
ensures the exposed pad of the device is maintained at a
given temperature (TEP), the junction temperature can be
estimated using the following formula:

where θ

T

J = TEP

is the junction-to-case thermal resistance of

JC

+ (θJC x P

LOSS

)

the device (8°C/W)

Adjusting the Output voltage

The MAX17620 supports output voltages from 1.5V to
100% VIN. Set the output voltage with a resistor-divider
connected from the positive terminal of the output voltage
to the ground (see Figure 1). Choose R2 in the range of

10kΩ to 100kΩ and calculate the R1 using the following

equation:



R1 x 1R2

= −

Power Dissipation

Ensure that the junction temperature of the device does
not exceed +125°C under the operating conditions. At a

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OUT



.8



Figure 1. Adjusting the Output Voltage

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│

12

LX

V

OUT

FB

GND

MODE

IN

PGOOD

EN

2.7V TO 5.5V

R1
24kΩ

V

OUT

1.8V/600mA

C

IN

2.2µF

L

1µH

MAX17620

CIN: 2.2µF/10V/0603/X7R,GRM188R71A225KE15D, MUR

ATA

L1: 1μH, 60mΩ, MAKK2016H1ROM, TAIYO-YUDEN
C

OUT

: 10μF/6.3V/0805/X7R, GRM21BR70J106KE76K, MURATA

C

OU

T

10µF

R2

19.1kΩ

MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

PCB Layout Guidelines

Careful PCB layout is critical to achieve clean and stable
operation. In particular, the traces that carry pulsating current
should be short and wide so that the parasitic inductance
formed by these traces can be minimized. Follow the
following guidelines for good PCB layout.

● Place the input capacitor as close as possible to the

IN and GND pins. Use a wide trace to connect the
input capacitor to the IN and GND pins to reduce the
trace inductance.

● Minimize the area formed by the LX pin and the inductor

connection to reduce the radiated EMI.

● Ensure that all the feedback connections are short.

● Route the LX node away from the FB, VOUT and

MODE pins.

Typical Application Circuit

For a sample PCB layout that ensures first-pass success,
refer to the MAX17620 evaluation kit layout available at

http://www.maximintegrated.com

Figure 2. 1.8V, 600mA Step-Down Regulator

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX17620ATA+T -40°C to +125°C 8 TDFN

+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.

Chip Information

PROCESS: CMOS

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.

PACKAGE

TYPE

8 TDFN T822+3C 21-0168 90-0065

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

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MAX17620 4MHz, Miniature 600mA, Synchronous Step-Down

DC-DC Converter with Integrated MOSFETs

Revision History

REVISION

NUMBER

0 3/15 Initial release —

1 6/15

REVISION

DATE

DESCRIPTION

Updated MODE pin description, updated global specications for the Typical
Operating Characteristics section, and updated table 1 and table 2

PAGES

CHANGED

4–6, 7, 9, 11

2 10/15

3 7/16 Fixed minor text errors 9, 11

Updated Typical Applications Circuit, replaced/added plots in Typical Operating
Characteristics section, and updated Block Diagram

1-6, 8, 10–11, 13

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.

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.

©

2016 Maxim Integrated Products, Inc.

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