EC5037|800kHz Synchronous Step-up Converter with 4A Switches

EC5037|800kHz Synchronous Step-up Converter with 4A Switches


規格書下載


800kHz ​​ Synchronous ​​ Step-up ​​ 

EC5037

 

Converter ​​ with ​​ 4A ​​ Switches

 

 

Description

The​​ EC5037 devices provide a power supply​​ solution ​​ for ​​ products ​​ powered ​​ by ​​ either ​​ a​​ one-cell ​​ Li-Ion ​​ or ​​ Li-polymer  ​​​​ battery. ​​ The​​ converter ​​ generates ​​ a ​​ stable ​​ output ​​ voltage​​ that ​​ is ​​ either ​​ adjusted ​​ by an ​​ external ​​ resistor​​ divider  ​​​​ or

fixed ​​ internally ​​ on ​​ the ​​ chip.​​ ​​ It​​ provides ​​ high ​​ efficient ​​ power ​​ conversion ​​ and​​ is ​​ capable ​​ of ​​ delivering ​​ output ​​ currents

up ​​ to​​ 1.5A ​​ at ​​ 5V ​​ at ​​ a ​​ supply ​​ voltage ​​ down ​​ to ​​ 3V.​​ The ​​ maximum ​​ peak ​​ current ​​ in ​​ the ​​ step-up​​ switch is limited to a

value of 4A. The​​ EC5037​​ operates ​​ at ​​ 800kHz ​​ switching ​​ frequency ​​ and​​ enters  ​​​​ pulse-skip-mode  ​​​​ (PSM)  ​​​​ operation  ​​​​ at

light load currents to maintain high efficiency​​ over ​​ the ​​ entire ​​ load ​​ current ​​ range. ​​ During​​ shutdown,​​ the​​ load​​ is​​ completely

disconnected from the battery.

 

Features

Synchronous Step-up Converter with 2.5A

Output Current From 3V Input

Wide VIN Range From 2.5V to 5.5V

Input Under-voltage Lockout Protection

Fixed and Adjustable Output Voltage

Built-in Output Over-voltage Protection

Light-Load Pulse Skip Mode

Load Disconnect During Shutdown

Output Short Circuit Protection

Thermal Shutdown Protection

Available in a DFN3x3mm_10L Packages

RoHS Compliant (100% Green Available)

 

Applications

Power Bank

USB Charging Port (5V)

DC/DC Micro Modules

Electrical Cigarettes

 

Ordering/Marking Information

 

EC5037​​ NN​​ ​​ X ​​​​ X​​ X

 

 ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​  ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​  ​​ ​​ ​​ ​​​​ ​​  ​​ ​​ ​​ ​​ ​​​​ RTape & Reel

​​ Package Type

 ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​  ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ FDFN3*3

 ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ GGreen Package

 

 

Part No.

Marking

Temp. Range

Package

MOQ

EC5037NNFGR

EC5037

LLLLL

YYWW

-40°C ~+85°C

DFN3*3

5,000/Reel

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1.​​ EC5037 Typical Application Circuit

 

Pin Configurations

 

 

 

 

 

 

 

 

 

 

EC5037​​ TOP View

 

Pin​​ Description

NAME

PIN NO

DESCRIPTION

VBAT

1

Input Supply voltage

SYNC

2

Enable/disable pulse skip mode (1: VBAT disabled, 0: GND enabled)

EN

3

Enable input. (1: VBAT enabled, 0: GND disabled)

FB

4

Voltage feedback of adjustable versions. Connect FB to GND and set fixed 5.1V​​ output voltage.

GND

5

Analog Ground pin. Connect GND to PGND under EP.

VOUT

6, 7

Step-up convert output

SW

8, 9

Step-up and rectifying switch input

PGND

10

Power Ground pin.

EP

 

Exposed pad must be soldered to achieve appropriate power dissipation. Connect​​ EP to GND.

 

 

 

 

 

 

 

 

 

 

Absolute Maximum Rating (1)

Supply Voltage (VIN)...……………...…….…-0.3V to +6V

Lead Temperature …….……………….………………… 260°C

Output Voltage (VOUT) ..……………….........​​  …-0.3V to +6V

Input Voltage (EN, FB, SW) ...….....​​  …..…..…-0.3V to +6V

Junction temperature range, TJ .……………… ​​ -40°C ~+135°C

Storage temperature range, Tstg ………..…..… -55°C~+155°C

Peak Output Current ………………..……. Internally limited

 

Recommend Operating Conditions (2)

Input Voltage (VIN) ………………………..… +2.9V to +5.5V

Operating Temperature Range ……………….. -40°C to +85°C

Output Voltage (VOUT) ………...……………. +2.9V to +5.5V

 

Thermal Information (3,4)

Maximum Power Dissipation(TA=+25°C ) ………….. 1.86W

DFN10 Thermal resistance(θJA) ………….………… 40.3°C/W

 

Note(1): Stress exceeding those listed “Absolute Maximum Ratings” may damage the device.

Note(2): The device is not guaranteed to function outside of the recommended operating conditions.

Note(3): Measured on JESD51-7, 4-Layer PCB.

Note(4): The maximum allowable power dissipation is a function of the maximum junction temperature TJ_MAX, the junction to​​ ambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any​​ ambient temperature is calculated by PD_MAX= (TJ_MAX-TA)/θJA. Exceeding the maximum allowable power dissipation will cause​​ excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device​​ from permanent damage.

 

Electrical characteristics

TA = +25°C, 2.9V ​​ ≤ VIN ≤ 5.5V, unless otherwise noted. Typical values are at VIN= VEN =3.6V and VOUT=5V.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Input voltage range VIN

 

2.5

 

5.5

V

Input Under-voltage Lockout Threshold VUVLO

 

 

2.2

 

V

Output voltage adjustable range VOUT

 

2.5

 

5.5

V

Feedback voltage VFB

 

490

500

510

mV

Oscillator frequency fOSC

 

640

800

960

kHz

NCH Switch Current Limit

VOUT= 5V

 

4

 

A

NCH Switch on resistance

VOUT= 5V

 

90

 

m

PCH Switch on resistance

VOUT= 5V

 

90

 

m

Shutdown Current

VEN = 0V, VIN = 3.6V

 

0.1

1

µA

Quiescent Current

VIN

VFB =0.55V , VOUT=5V

 

125

200

µA

EN logic low voltage

 

 

 

0.4

V

EN logic high voltage

 

1.4

 

 

V

EN leakage current

Clamped on GND or VIN

-1

 

1

µA

Thermal Shutdown

 

 

150

 

Thermal Shutdown Hysteresis

 

 

20

 

 

Functional Block Diagram

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2.​​ EC5037 Functional Block Diagram

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TYPICAL PERFORMANCE CHARACTERISTICS

VIN = 3.3V,​​ EC5037 typical application circuit (Figure 1.), TA = +25°C, unless otherwise noted.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Detailed Description

The​​ EC5037 is based on a fixed frequency current mode pulse width modulation topology. The peak current of the​​ NMOS switch is sensed to limit the maximum current flowing through the switch and the inductor. The typical peak​​ current limit is set to 4A. An internal temperature sensor prevents the device from getting overheated in case of​​ excessive power dissipation.

 

Application Information

Because ​​ of ​​​​ the ​​ high ​​ integration ​​ of ​​ EC5037, ​​ the ​​ application ​​ circuit ​​ is ​​ simple. ​​ Only ​​ input ​​ capacitor ​​ CIN, ​​ output​​ capacitor COUT, inductor L, output feedback resistors R3, R4 need to be selected for the targeted applications​​ specifications.

 

Switching Frequency Selections

The​​ EC5037 output voltage can be adjusted with an external resistor divider (See Figure 1). The typical value of​​ the voltage on the FB pin is 500mV. The maximum allowed value for the output voltage is 5.5 V. Choose the bottom​​ resistor ​​ R4 in the​​ 100kΩ~500kΩ ​​ 

range ​​ to ​​ set ​​ the ​​ divider ​​ current ​​ at ​​ 1 ​​ µA or ​​ higher. ​​ The ​​ value ​​ of ​​ resistor ​​ R3,​​ depending on the needed output voltage VOUT, can be calculated using Equation 1:

 

 

 

Inductor Selection

The ​​ EC5037 ​​ 800kHz ​​ high ​​ switching ​​ frequency ​​ allows ​​ for ​​ the ​​ use ​​ of ​​ small ​​ surface ​​ mount ​​ inductors. ​​ For ​​ high​​ efficiency, ​​ choose ​​ inductors ​​ with ​​ high ​​ frequency ​​ core ​​ material, ​​ such ​​ as ​​ ferrite, ​​ to ​​ reduce ​​ core ​​ losses. ​​ Also ​​ to​​ improve efficiency, choose inductors with bigger size for a given inductance. The inductor should have low DCR​​ (copper-wire ​​ resistance) ​​ to ​​ reduce ​​ I2R ​​ losses, ​​ and ​​ must ​​ be ​​ able ​​ to ​​ handle ​​ the ​​ peak ​​ inductor ​​ current ​​ without​​ saturating. The inductor DC current rating should be greater than the maximum input average current. For the full​​ 2.5Amp output current applications, the inductor shall have enough core volume to support peak inductor currents​​ up to 3.5A range and DCR less than 30mΩ. The highest peak current through the inductor and the switch depends​​ on the output load, converter efficiency η, the input voltage (VBAT), and the output voltage (VOUT). Estimation of the​​ maximum average inductor current can be done using Equation 3:

 

 

For example, for an output current of 1.5A at 5V with 85% efficiency, at least 3A of average current flows through​​ the inductor at a minimum input voltage of 3V.

 

The inductor value has a direct effect on ripple current. Let the parameter ∆IL represent the inductor peak-peak ripple current. The

inductor ripple current contributes to the output current ripple that must be filtered by the output capacitor. Therefore, choosing

high inductor ripple currents impacts the selection of the output capacitor. Higher values of ∆IL lead to discontinuous mode (DCM)

operation at moderate to light loads. The inductor ripple current ∆IL decreases with higher inductance or frequency and increases

with higher VIN. Estimation of the inductor ripple current can be done using Equation 3:

 

 

The​​ EC5037 step-up converters can operate with an effective inductance in the range of 1µH to 2.2µH and with​​ output capacitors in the range of 20µF to 100µF. The internal compensation is optimized for an output filter of L =​​ 1.5µH and COUT = 20µF. To minimize radiated noise, use a toroidal or shielded inductor.

 

Input Capacitor

Place at least a 10 µF input ceramic capacitor close to the IC is to improve transient behavior of the regulator and​​ EMI behavior of the total power supply circuit.

 

Output Capacitor

The ​​ output capacitor must completely supply ​​ the ​​ load ​​ during ​​ the ​​ charging ​​ phase ​​ of the ​​ inductor. ​​ A reasonable​​ value of the output capacitance depends on the speed of the load transients and the load current during the load​​ change. It is recommended to use X7R ceramic capacitors placed as close as possible to the VOUT and PGND​​ pins of the IC. A recommended output capacitance value is around 20~47µF.

 

 

Layout consideration

Use wide and short traces for the main current path and for the power ground tracks. The input capacitor, output​​ capacitor, and the inductor should be placed as close as possible to the IC. Use a common ground node for power​​ ground and a different one for analog ground to minimize the effects of ground noise. Connect these ground nodes​​ at any place close to the ground pins of the IC.

 

Thermal information

Implementation of integrated circuits in low-profile and fine-pitch surface-mount packages typically requires special​​ attention to power dissipation. Many system-dependent issues such as thermal coupling, airflow, added heat sinks​​ and convection surfaces, and the presence of other heat-generating components affect the power-dissipation limits​​ of a given component.

 

Three basic approaches for enhancing thermal performance are listed below:

High speed switching path (SW, PGND and VOUT with wide PCB traces) must be kept as short as possible.

Solder the​​ EC5037 PGND and GND pins to the ground plane.

Choose a bigger size 1.5uH Inductor with the lowest DCR value for given PCB space

 

The ​​ maximum ​​ junction ​​ temperature ​​ (TJ) ​​ of the ​​ EC5037 ​​ devices ​​ is ​​ 125℃.The ​​ thermal ​​ resistance ​​ of ​​ the ​​ DFN10​​ package ​​ is ​​ RθJA ​​ = ​​ 40.3℃/W, ​​ if ​​ the ​​ Exposed ​​ PAD ​​ is ​​ soldered. ​​ Specified ​​ regulator ​​ operation ​​ is ​​ assured ​​ to ​​ a​​ maximum ambient temperature TA of +50℃. Therefore, the maximum power dissipation for the DFN10 package it​​ is about 1.86W. More power can be dissipated if the maximum ambient temperature of the application is lower.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Packaging Information

DFN3*3