SC1537CMTRT [SEMTECH]

Fixed Positive LDO Regulator, 3.3V, PSSO5, TO-263, 5 PIN;


型号：	SC1537CMTRT
厂家：	SEMTECH CORPORATION
描述：	Fixed Positive LDO Regulator, 3.3V, PSSO5, TO-263, 5 PIN
文件：	总7页 (文件大小：98K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

DESCRIPTION

FEATURES

•= Glitch-free transition between input sources

•= Internal logic selects input source

•= Gate drive for external PMOS bypass switch

•= 5V detector with hysteresis

The SC1537 is designed to maintain a glitch-free 3.3V

output when at least one of two inputs, 5V (VIN) and

3.3V (VAUX), is present.

•= 1% regulated output voltage accuracy

•= 700mA load current capability

Whenever VIN exceeds a predetermined threshold

value, the internal 3.3V linear regulator is enabled, and

DR is pulled high.

•= SO-8 and TO-263 packages

When VIN falls below a lower threshold value, DR is

pulled low and the internal linear regulator is turned off.

DR has been designed to drive the gate of an external

low threshold P-channel MOSFET, which can be used

to connect the 3.3V supply directly to the regulator

output. This ensures an uninterrupted 3.3V output even

if VIN falls out of specification. A maximum R_DS(ON)of

100mΩ is recommended.

APPLICATIONS

•= Desktop Computers

•= Network Interface Cards (NICs)

•= PCMCIA/PCI Interface Cards

•= Cardbus^TMTechnology

•= Power supplies with multiple input sources

When both supplies are simultaneously available, the

drive pin (DR) will be pulled High, turning off the exter-

nal PMOS switch.

ORDERING INFORMATION

Part Number⁽¹⁾

SC1537CSTR

SC1537CMTR

Package

SO-8

The internal 5V detector has its upper threshold (for

VIN rising) set to 4.22V (typical) while the lower thresh-

old (for VIN falling) is at 4.05V (typical) giving a hystere-

sis of approximately 170mV.

TO-263-5L

Note:

(1) Only available in tape and reel packaging. A reel con-

tains 2500 devices for SO-8 and 800 devices for TO-263.

The SC1537 is available in the popular SO-8 and

5-lead TO-263 surface mount packages.

APPLICATION CIRCUIT

3.3V OUT

U1 SC1537CS

3.3V

VAUX GND

VIN

GND

10uF

0.1uF

10uF

0.1uF

SC1537CM

TAB

VIN

3.3V

3.3V OUT

VAUX

GND

0.1uF

10uF

0.1uF

10uF

0.1uF

NOTE:

(1) External switch (Q1): use a low threshold P-channel MOSFET such as Vishay Si2305DS (R_DS(ON)< 71mΩ at

V_GS= 2.5V) or International Rectifier IRLML6401 (R_DS(ON)< 85mΩ at V_GS= 2.5V), or equivalent.

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

ABSOLUTE MAXIMUM RATINGS

Parameter

Symbol

VIN

Maximum

-0.5 to +7

10 to 700

0 to +70

Units

Input Supply Voltage

Auxiliary Supply Voltage

VAUX

I_O

LDO Output Current

°C

Operating Ambient Temperature Range

Operating Junction Temperature Range

Storage Temperature Range

Lead Temperature (Soldering) 10 Sec

T_A

T_J

0 to +125

-65 to +150

300

T_STG

T_LEAD

Thermal Impedance Junction to Ambient

SO-8⁽¹⁾

TO-263

°C/W

θ_JA

Thermal Impedance

Junction to Case

SO-8

°C/W

θ_{J C}

TO-263

ESD Rating (Human Body Model)

ESD

Note:

(1) 1 inch square of 1/16” FR-4, double sided, 1 oz. minimum copper weight.

ELECTRICAL CHARACTERISTICS

Unless specified, T_A= 25°C, VIN = 5V, VAUX = 3.3V, I_O= 700mA, C_O= 10µF. Values in bold apply over full operating temperature range.

Parameter

VIN

Symbol

Test Conditions

MIN TYP MAX Units

Supply Voltage

Quiescent Current

VIN

I_Q

VAUX = 0V

4.75 5.00 5.25

VIN = 5V, VAUX = 0V, I_O= 0mA

9.0

14.0

16.0

VIN = 5V, VAUX = 3.3V, I_O= 0mA

VAUX = 3.6V, VIN = 0V, I_O= 0mA

13.0 17.0

18.0

Reverse Leakage From VAUX

I_VIN

-1.5

-3.0

-4.0

VAUX

Supply Voltage

Quiescent Current

VAUX

I_Q(AUX)

3.0

3.3

3.6

11.0

13.0

2.5

VAUX = 3.3V, VIN = 0V, I_O= 0mA

VAUX = 3.3V, VIN = 5V, I_O= 0mA

8.0

1.5

3.0

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

ELECTRICAL CHARACTERISTICS

Unless specified, T_A= 25°C, VIN = 5V, VAUX = 3.3V, I_O= 700mA, C_O= 10µF. Values in bold apply over full operating temperature range.

Parameter

Symbol

Test Conditions

MIN

TYP

MAX Unit

VAUX (Cont.)

Reverse Leakage From VIN

I_VAUX

VIN = 5.5V, VAUX = 0V, I_O= 0mA

-5.0

-50.0 µA

100.0

5V Detect^(1)(2)(3)

Low Threshold Voltage

V_TH(LO)

V_HYST

V_TH(HI)

VIN Falling, I_O= 20mA

VIN Rising, I_O= 20mA

3.92

3.90

4.05

170

4.18

4.20

Hysteresis

High Threshold Voltage

4.35

LDO Output Voltage

I_O= 20mA

3.267 3.300

3.333

3.366

400

3.234

4.75V ≤ VIN ≤ 5.25V, 0mA ≤ I_O≤ 700mA

Output Current

Line Regulation

I_O

REG_(LINE)

VIN = 4.75V to 5.25V

I_O= 10mA to 700mA

0.20

0.6

0.60

0.80

1.0

Load Regulation

REG_(LOAD)

1.2

Drive Output

Drive Voltage

V_DR

3.4 VIN - 0.8

4.75V ≤ VIN ≤ 5.25V, I_DR= 200µA

3.3

VIN < V_TH(LO), I_DR= -200µA

150

µs

250

Peak Drive Current

Drive High Delay⁽¹⁾⁽⁴⁾

Drive Low Delay⁽¹⁾⁽⁴⁾

I_DR(PK)

Sinking: VIN = 3.9V, V_DR= 1V;

Sourcing: VIN = 4.35V, VIN - V_DR= 2.5V

C_DR= 1.2nF, VIN ramping up, measured

from VIN = V_TH(HI)to V_DR= 2V

t_DH

0.5

1.0

2.0

1.0

t_DL

C_DR= 1.2nF, VIN ramping down,

measured

0.5

µs

from VIN = V_TH(LO)to V_DR= 2V

2.0

NOTES:

(1) Guaranteed by design.

(2) See 5V Detect Thresholds on page 5.

(3) Recommended source impedance for 5V supply: ≤ 0.07Ω. This will ensure that I_Ox R_SOURCE< V_HYST, thus

avoiding DR toggling during 5V detect threshold transitions.

(4) See Timing Diagram on page 5.

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

BLOCK DIAGRAM

PIN CONFIGURATION

Top View

SO-8

TO-263-5L

PIN DESCRIPTION

Pin Name

SO-8 Pin #

TO-263-5L Pin # Pin Function

Driver output for external P-channel MOSFET pass element.

GND

VAUX

VIN

5,6,7,8

3/TAB

Logic and power ground.

This is the auxiliary input supply, nominally 3.3V.

This is the main input supply for the IC, nominally 5V.

LDO 3.3V output.

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

5V DETECT THRESHOLDS

NOTE:

(1) VIN rise and fall times (10% to 90%) to be ≥=100µs.

TIMING DIAGRAM

NOTE:

(1) VIN rise and fall times (10% to 90%) to be ≤=100ns.

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

OUTLINE DRAWING - SO-8

JEDEC

REF: MS-012AA

MINIMUM LAND PATTERN - SO-8

652 MITCHELL ROAD NEWBURY PARK CA 91320

700mA SmartLDO^TM

SC1537

PRELIMINARY - July 25, 2000

DEVICE OUTLINE - TO-263, 5 PIN

MINIMUM LAND PATTERN - TO-263, 5 PIN

ECN00-1177

652 MITCHELL ROAD NEWBURY PARK CA 91320

SC1537CMTRT [SEMTECH]

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