Impala Linear Corporation ILC6377SO-ADJ, ILC6377SO-50, ILC6377SO-33 Datasheet

Impala Linear Corporation

1

[phone]

www.impalalinear.com

June 1999

ILC6377 1.3

The ILC6377 is a 95% efficient, 300kHz step-down DC-DC
converter in an SO-8 package; capable of delivering 500mA
output current. The device is also capable of driving an
external FET for higher output current applications.

The ILC6377 uses a unique p-channel architecture with
built-in charge pump to maintain low on-resistance, even at
low input voltages. At high or normal currents the ILC6377
operates in PWM mode with 300kHz operating frequency.
When the load current drops and the device hits approxi­mately 17% duty cycle, it automatically switches over to
PFM or pulse skipping mode. PFM (pulse frequency mod­ulation) mode of operation extends efficiency at light loads.

Start-up is controlled via an external soft-start capacitor. The
device will automatically re-enter start-up mode when an
output current overload condition is sensed; thus providing
automatic short-circuit protection. Voltage lockout prevents
faulty operation below the minimum operating voltage level.
In shutdown, the ILC6377 consumes only 1.5mA current.

The ILC6377SO-XX offers fixed 3.3V or 5V ouput while
ILC6377SO-Adj allows adjustable output. Both versions of
ILC6377 are available in an SO-8 surface mount package.

! ±2.5% accurate output voltages
! Guaranteed 500mA output current
! 95% efficiency
! 55mA no load battery input current
! 1.5mA shutdown current
! Built in short circuit and overcurrent protection
! Undervoltage lockout and soft-start
! External transistor drive available for higher Iout
! 300kHz operation
! Automatic switchover to PFM mode at low

currents for longest battery life

! Fixed 3.3V or 5V or adjustable output
! SO-8 package

! Cellular Phones
! Palmtops and PDAs
! Portable Instrumentation
! Buck Converter for Industrial / Networking Applications

PWM/PFM

Protection

L

X

GND

EXT1

RA MP WAVE

V

IN

V

OUT

P_BST

GA TE
DR IV ER

GENERATOR,
OSCILLATORCONTROLLER

+

-

PWM
Comp

EXT2

+

-

Error
Amp

1
5

4

6

3

2

7

8

S/D,

Softstart,

Vref

S/D,
Vref

with
Soft-

start

ILC6377

(TOP VIEW)

3
45

1
2

6

7

8 L

X

FB

EXT1

S/D,

GND

P_BST

EXT2

V

IN

ILC6377SO-Adj

C

SS

SO-8 Package

ILC6377

(TOP VIEW)

3

L

X

V

OUT

EXT1

45S/D,

GND

1
2

6

7

8

P_BST

EXT2

V

IN

C

SS

SO-8 Package

ILC6377SO-XX

Ordering Information

ILC6377SO-33 3.3V, 300 kHz step-down PWM/PFM converter
ILC6377SO-50 5V, 300 kHz step-down PWM/PFM converter
ILC6377SO-Adj Adjustable, 300 kHz step-down PWM/PFM converter

Pin

Symbol

Function

1

VIN

Power Supply

2

EXT2

External gate drive pin (low when
P-Ch FET is ON)

3

P-BST

P-Ch gate boost

4

S/D

Softstart, V

ref

Shutdown, also soft-start capacitor
pin and V

ref

output

5

V

OUT

/FB

Output voltage sense pin for
ILC6377SO-XX; 1V feedback for
ILC6377SO adj

6

GND

Ground connection

7

EXT1

External gate drive pin (low when
P-Ch FET is on)

8

LX

Inductor switch pin

ILC6377

0.5A, 300kHz, SO-8 PWM/PFM Step Down
Converter with Shutdown

Impala Linear Cor poration

General Description

Features

Applications

Block Diagram

Pin Package Configurations

Pin Description

0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with Shutdown

Impala Linear Corporation

2

[phone]

www.impalalinear.com

June 1999

ILC6377 1.3

Conditions

V

IN

3.5V, No Loads

V

S/D

= 0V

Open Loop Measurement, V

S/D

= VIN, V

LX

=

VIN- 0.4V , V

OUT

= 3V

Open Loop Measurement, V

OUT

= VIN,

V

LX

= 0V

Measurement Waveform at EXT pin VIN=

3.6V I

OUT

= 20mA

No Load

Minimum V

IN

when V

ref

does not start up

V

ref

rises to 0V from 0.9V

Parameter

Output Voltage

Input Voltage

Output Voltage

Input Current Supply

Shutdown Current

LX Switch On - Resistance

LXSwitch Leakage Current

Oscillator Frequency

Max Duty Cycle
PFM Duty Cycle

Efficiency

Undervoltage Lockout

Soft-Start Time

Symbol

V

OUT

V

IN

I

OUT

I

IN

I

S/D

R

ds(on)

I

LXL

F

OSC

MAXDTY

PFMDTY

EFFI

V

UVLO

T

SS

Unless Otherwise specified all limits are at V

OUT

= 3.3V, VIN= 4V, F

OSC

=300kHz, I

OUT

= 130mA,TA= 25°C. Circuit configuration of figure 1.

Parameter

V

IN

Input Voltage Pin

V

OUT

Pin (ILC6370SO-XX)

FB Pin (ILC6377SO-Adj)
Voltage on LXpin
Peak Switch Current on LXpin
Voltage on P_BST pin
Current EXT1, EXT2 pins
Voltage on all other pins
Continuous Total Power Dissipation
Operating Ambient Temperature
Storage Temperature

Symbol

V

IN

V

OUT

V

FB

V

LX

I

LX

VDP_BST

I

EXT1, IEXT2

~

P

D

T

OPR

T

STG

Ratings

-0.3 to +12

-0.3 to +12

-0.3 to VIN+12

VIN- V

LX

= 0.3 to +12

700

VIN- VP_BST = 0.3 to +12

±50

-0.3 to V

IN

500

-30~+80

-40~+125

Units

V
V

V

mA

V

mA

V

mA

°C
°C

Typ

3.300

600

55

1.5

0.64

300

100

17

95

10.0

Min

3.218

500

255

10

1

6.0

Max

3.383

10

86

2.5

0.85

2.0

345

25

1.8

16.0

Units

V

V

mA

µA

µA

Ω

µA

kHz

%

%

%

V

msec

Absolute Maximum Ratings (TA=25°C)

Electrical Characteristics ILC6377SO-33

0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with Shutdown

Impala Linear Corporation

3

[phone]

www.impalalinear.com

June 1999

ILC6377 1.3

Min

4.875

500

255

10

1

6.0

3.0

0.65

Typ

5.000

600

71

1.5

0.44

300
100

17
95

10.0

5.0

24
20

Symbol

V

OUT

V

IN

I

OUT

I

IN

I

S/D

R

ds(on)

I

LXL

F

OSC

MAXDTY
PFMDTY

EFFI

V

UVLO

T

SS

T

PRO

V

S/D

REXt

HI

REXt

LOW

Parameter

Output Voltage
Input Voltage
Output Current
Input Supply Current
Shutdown Current

LXSwitch On-Resistance

LXSwitch Leakage Current

Oscillator Frequency
Max Duty Cycle

PFM Duty Cycle
Efficiency
Undervoltage Lockout
Soft-Start Time
Internal Protection Time

Shutdown Input Voltage

EXT1, EXT2 Hi On-Resistance
EXT1, EXT2 Low On-Resistance

Parameter

Internal Protection Time

Shutdown Input Voltage

EXT1, EXT2 Hi On-Resistance

EXT1, EXT2 Low On-Resistance

Symbol

T

PRO

V

SD

REXt

HI

REXt

LOW

Conditions

Time from V

OUT

= 0V to V

S/D

going low

High = Regulator “ON”
Low = Regulator “OFF”

3V applied to V

OUT

with no external components

3.6V applied to V

OUT

with no external components

Min

3.0

0.65

Typ

5.0

3.5

29

Max

8.0

0.2

47

37

Units

Msec

V

Ω

Ω

Conditions

V

IN

5.25V, No Load

V

S/D

= 0V

Open Loop Measurement, V

S/D

= VIN,

V

LX =VIN

- 0.4V, V

OUT

= 4.5V

Open Loop Measurement, V

OUT

= VIN,

VLX= 0V
Measure Waveform at EXT pin V

IN

= 5.3V

I

OUT

= 20mA

No Load

Minimum VINwhen V

ref

does not start up

V

ref

rises to 0V from 0.9V

Time form V

OUT

m = 0V to V

S/D

going low

High = Regulator “ON”
Low = Regulator “OFF”

Open Loop Measurement
Open Loop Measurement

Max

5.125
10

110

2.5

0.58

2.0

345

25

1.8

16.0

8.0

0.2

32
26

Units

V
V

mA

µA
µA

Ω

µA

kHz

%
%

%

V
msec
msec

V

Ω

Ω

Electrical Characteristics ILC6377SO-33

Electrical Characteristics ILC6377SO-50

Unless Otherwise specified all limits are at V

OUT

= 3.3V, VIN= 4V, F

OSC

=300kHz, I

OUT

= 130mA,TA= 25°C. Circuit configuration of figure 1.

Unless Otherwise specified all limits are at V

OUT

= 5.0V, VIN= 6V, F

OSC

=300kHz, I

OUT

= 200mA, TA= 25°C. Circuit configuration of figure 1.

0.5A, 300kHz, SO-8 PWM/PFM Step Down Converter with Shutdown

Impala Linear Corporation

4

[phone]

www.impalalinear.com

June 1999

ILC6377 1.3

Parameter Symbol Conditions Min Typ Max Units

Feedback Voltage (pin5) V

FB

.995 1.000 1.015 V

Input Voltage V

OUT

R

FB1

+ R

FB2

< 2MΩ 38V

Output Current I

OUT

500 600 mA

Input Supply Current I

IN

VIN5.25V, No Load 71 110 µA

Shutdown Current I

S/D

V

S/D

= 0V 1.5 2.5 µA

LX Switch On-Resistance R

ds(on)

Open Loop Measurement, V

S/D

= VIN, 0.44 0.58 Ω

V

LX

= VIN- 0.4V, V

OUT

= 4.5V

LX Switch On-Resistance I

LXL

Open Loop Measurement, V

OUT

= VIN, 2.0 µA

V

LX

= 0V

Shutdown Input Voltage V

S/D

High = Regulator “ON” 0.65 0.2 V
Low = Regulator “OFF”

Oscillator Frequency F

OSC

Measure Waveform at EXT pin VIN= 255 300 345 kHz

5.3V I

OUT

= 20mA

Max Duty Cycle MAXDTY 100 %
PFM Duty Cycle PFMDTY No Load 10 17 25 %
Efficiency EFFI 95 %

Undervoltage Lockout V

UVLO

Minimum VINwhen V

ref

does not start up 1 1.8 V

Soft-Start Time T

SS

V

ref

rises to 0V from 0.9V 6.0 10.0 16.0 msec

Internal Protection Time T

PRO

Time from V

OUT

m = 0V to V

S/D

going low 3.0 5.0 8.0 msec

EXT1, EXT2 Hi On-Resistance REXt

HI

Open Loop Measurement 24 32 Ω

EXT1, EXT2 Low On-Resistance REXt

LOW

Open Loop Measurement 20 26 Ω

Electrical Characteristics ILC6377SO-Adj

Unless Otherwise specified all limits are at V

OUT

programmed to 5.0V, VIN= 6V, F

OSC

=300kHz, I

OUT

= 200mA, TA= 25°C. Circuit configuration of figure 1.