AAT4280AIJS-2-T1 - AnalogicTech

General Description

The AAT4280A SmartSwitch™ is a member of

AnalogicTech's Application Specific Power MOS-

FET™ (ASPM™) product family. The AAT4280A is

a P-channel MOSFET power switch designed for

high-side load-switching applications. The device

has a typical RDS(ON) of 80mΩ, allowing increased

load switch power handling capacity and is avail-

able in three different versions with flexible turn-on

and turn-off characteristics -- from very fast to slew

rate limited. The standard AAT4280A (-1) version

has a slew rate limited turn-on load switch and is

functionally compatible with the AAT4250 device,

while offering superior RDS(ON) characteristics. The

AAT4280A (-2) version features fast load switch

turn-on capabilities, typically less than 500ns turn-

on and 3µs turn-off times. The AAT4280A (-3) vari-

ation offers a shutdown load discharge circuit to

rapidly turn off a load circuit when the switch is dis-

abled. All AAT4280A load switch versions operate

with an input voltage ranging from 1.5V to 5.5V,

making them ideal for both 3V and 5V systems.

Input logic levels are TTL and 2.5V to 5V CMOS

compatible. The quiescent supply current is very

low, typically 25nA.

The AAT4280A is available in a 6-pin SOT23 or an

8-pin SC70JW package and is specified over the

-40°C to 85°C temperature range.

Features

• 1.5V to 5.5V Input Voltage Range

• Very Low RDS(ON), Typically 80mΩ(5V)

• Slew Rate Limited Turn-On Time Options

• 1ms

• 0.5µs

• 100µs

• Fast Shutdown Load Discharge Option

• Low Quiescent Current

• 25nA (typ)

• TTL/CMOS Input Logic Level

• Temperature Range: -40ºC to 85°C

• 4kV ESD Rating

• 6-Pin SOT23 or 8-Pin SC70JW Package

Applications

• Cellular Telephones

• Digital Still Cameras

• Hot Swap Supplies

• Notebook Computers

• Personal Communication Devices

• Personal Digital Assistants (PDAs)

AAT4280A

Slew Rate Controlled Load Switch

Typical Application

AAT4280A

COUT

0.1µF

CIN

1µF

OUTIN

GND

VOUT

GND

VIN

ON/OFF GND

4280A.2004.11.1.0 1

SmartSwitch™

AAT4280A

Slew Rate Controlled Load Switch

24280A.2004.11.1.0

Pin Descriptions

Pin Configuration

SOT23-6

(Top View)

SC70JW-8

(Top View)

Selector Guide

Slew Rate Active

Part Number (typ) Pull Down Enable

AAT4280A-1 1mS Active High

AAT4280A-2 0.5µS Active High

AAT4280A-3 100µS √Active High

OUT

ON/OFF

GND

IN 1

GND

ON/OFF

OUT

Pin #

SOT23-6 SC70JW Symbol Function

1 2 OUT The pin is the P-channel MOSFET drain connection.

Bypass to ground through a 0.1uF capacitor.

2, 5 4 GND Ground connection.

3 3 ON/OFF Enable input.

4, 6 1, 5, 6, 7, 8 IN The pin is the input to the P-channel MOSFET source.

Bypass to ground through a 1.0uF capacitor.

AAT4280A

Slew Rate Controlled Load Switch

4280A.2004.11.1.0 3

Absolute Maximum Ratings (TA=25°C unless otherwise noted)

Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con-

ditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.

Note 1: Human body model is a 100pF capacitor discharged through a 1.5kΩresistor into each pin.

Thermal Characteristics

Note 2: Mounted on an AAT4280A demo board in still 25ºC air.

Value

Symbol Description SOT23-6 SC70JW-8 Units

ΘJA Thermal Resistance (SOT23-6 or SC70JW-8)2120 140 °C/W

PDPower Dissipation (SOT23-6 or SC70JW-8)2833 714 mW

Symbol Description Value Units

VIN IN to GND -0.3 to 6 V

VON ON/OFF to GND -0.3 to 6 V

VOUT OUT to GND -0.3 to VIN+0.3 V

IMAX Maximum Continuous Switch Current 2.3 A

IDM Maximum Pulsed Current IN ≥2.5V 6 A

IN < 2.5V 3 A

TJOperating Junction Temperature Range -40 to 150 °C

TLEAD Maximum Soldering Temperature (at leads) 300 °C

VESD ESD Rating1- HBM 4000 V

AAT4280A

Slew Rate Controlled Load Switch

44280A.2004.11.1.0

Electrical Characteristics

Unless otherwise noted, VIN = 5V, TA= 40 to 85°C; typical values are at TA=25°C.

Note 3: For VIN outside this range, consult typical ON/OFF threshold curve.

Symbol Description Conditions Min Typ Max Units

AAT4280A All Versions

VIN Operation Voltage 1.5 5.5 V

IQQuiescent Current ON/OFF= active 1 µA

IQ(off) Off Supply Current ON/OFF= inactive, OUT=open 1 µA

ISD(off) Off Switch Current ON/OFF= inactive, VOUT=0 1 µA

RDS(on) On-Resistance VIN=5V, TA=25° C 80 120 mΩ

VIN=4.2V, TA=25° C 85 130

VIN=3V, TA=25° C 100 150

VIN=1.8V, TA=25° C 160 250

TCRDS On-Resistance Temp -Co 2800 ppm/°C

VIL ON/OFF Input Logic Low Voltage VIN=1.8V-5.5V 30.4 V

VIN=2.7V to 4.2V 2

VIH ON/OFF Input Logic High Voltage VIN= 4.2V to 5.5V 2.4 V

VIN= 1.5V to 2.7V 1.4

ISINK ON/OFF Input Leakage VON/OFF= 5.5V 1 µA

AAT4280A-1

TD(ON) Output Turn-On Delay VIN =5V, RLOAD=10Ω, TA=25° C 20 40 µS

TON Output Turn-On Rise Time VIN =5V, RLOAD=10Ω, TA=25° C 1000 1500 µS

TD(OFF) Output Turn-Off Delay Time VIN =5V, RLOAD=10Ω, TA=25° C 4 10 µS

AAT4280A-2

TD(ON) Output Turn-On Delay VIN =5V, RLOAD=10Ω, TA=25° C 0.5 2 µS

TON Output Turn-On Rise Time VIN =5V, RLOAD=10Ω, TA=25° C 0.5 1 µS

TD(OFF) Output Turn-Off Delay Time VIN =5V, RLOAD=10Ω, TA=25° C 4 10 µS

AAT4280A-3

TD(ON) Output Turn-On Delay VIN =5V, RLOAD=10Ω, TA=25° C 20 40 µS

TON Output Turn-On Rise Time VIN =5V, RLOAD=10Ω, TA=25° C 100 150 µS

TD(OFF) Output Turn_Off Delay Time VIN =5V, RLOAD=10Ω, TA=25° C 4 10 µS

RPD Output pull-down resistance during OFF ON/OFF = inactive, TA=25° C 150 250 Ω

AAT4280A

Slew Rate Controlled Load Switch

4280A.2004.11.1.0 5

Typical Characteristics

Unless otherwise noted, VIN = 5V, TA= 25°C.

Off Switch Current vs. Temperature

0.001

0.010

0.100

1.000

-40 -20 0 20 40 60 80 100

Temperature (°C)

IOFFSW (µA)

ON/OFF Threshold vs. VIN

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VIN (V)

ON/OFF Threshold (V)

VIH

VIL

RDS(ON) vs. Temperature

100

110

120

-40 -20 0 20 40 60 80 100

Temperature (°C)

RDS(ON) (mΩ)

VIN=5V

VIN=3V

RDS(ON) vs. VIN

110

130

150

170

190

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VIN (V)

RDS(ON) (mΩ)

500mA

100mA

Quiescent Current vs. Temperature

Temperature (°C)

IQ (nA)

-40 -20 0 20 40 60 80 100

AAT4280A

Slew Rate Controlled Load Switch

64280A.2004.11.1.0

Typical Characteristics—4280A-1

Unless otherwise noted, VIN = 5V, TA= 25°C.

AAT4280A-1 Turn-Off

VIN=5V RL=10Ω

Time (10µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-1 Turn-Off

VIN=3V RL=6Ω

Time (10µs/div)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-1 Turn-On

VIN=5V RL=10Ω

Time (500µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-1 Turn-On

VIN=3V RL=6Ω

Time (500µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A

Slew Rate Controlled Load Switch

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Typical Characteristics—4280A-2

Unless otherwise noted, VIN = 5V, TA= 25°C.

AAT4280A-2 Turn-Off

VIN=5V RL=10Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-2 Turn-Off

VIN=3V RL=6Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-2 Turn-On

VIN=5V RL=10Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-2 Turn-On

VIN=3V RL=6Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A

Slew Rate Controlled Load Switch

84280A.2004.11.1.0

Typical Characteristics—4280A-3

Unless otherwise noted, VIN = 5V, TA= 25°C.

AAT4280A-3 Turn-Off

VIN=5V RL=10Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-3 Turn-Off

VIN=3V RL=6Ω

Time (5µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-3 Turn-On

VIN=5V RL=10Ω

Time (50µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A-3 Turn-On

VIN=3V RL=6Ω

Time (50µs/div.)

ON/OFF (5V/div.)

VOUT (2V/div.)

IIN (200mA/div.)

AAT4280A

Slew Rate Controlled Load Switch

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Functional Description

The AAT4280A is a family of flexible P-channel

MOSFET power switches designed for high-side

load switching applications. There are three ver-

sions of the AAT4280A with different turn-on and

turn-off characteristics to choose from, depending

upon the specific requirements of an application.

The first version, AAT4280A-1, has a moderate

turn-on slew rate feature, which reduces in-rush

current when the MOSFET is turned on. This func-

tion allows the load switch to be implemented with

a small input capacitor, or no input capacitor at all.

During turn-on slewing, the current ramps linearly

until it reaches the level required for the output load

condition. The proprietary turn-on current control

method works by careful control and monitoring of

the MOSFET gate voltage. When the device is

switched ON, the gate voltage is quickly increased

to the threshold level of the MOSFET. Once at this

level, the current begins to slew as the gate voltage

is slowly increased until the MOSFET becomes

fully enhanced. Once it has reached this point, the

gate is quickly increased to the full input voltage

and RDS(ON) is minimized. The second version, the

AAT4280A-2, is a very fast switch intended for

high-speed switching applications. This version

has no turn-on slew rate control and no special out-

put discharge features. The final switch version,

the AAT4280A-3, has the addition of a minimized

slew rate limited turn-on function and a shutdown

output discharge circuit to rapidly turn off a load

when the load switch is disabled through the

ON/OFF pin.

All versions of the AAT4280A operate with input

voltages ranging from 1.5V to 5.5V. All versions of

this device have extremely low operating current,

making them ideal for battery-powered applica-

tions. The ON/OFF control pin is TTL compatible

and will also function with 2.5V to 5V logic systems,

making the AAT4280A an ideal level shifting load-

switch.

Functional Block Diagram

Level

Shift

ON/OFF

OUT

GND

Turn-On

Slew Rate

Control

*AAT4280A-3 only

AAT4280A

Slew Rate Controlled Load Switch

10 4280A.2004.11.1.0

Applications Information

Input Capacitor

Typically a 1µF or larger capacitor is recommend-

ed for CIN in most applications. A CIN capacitor is

not required for basic operation; however, CIN is

useful in preventing load transients from affecting

upstream circuits. CIN should be located as close

to the device VIN pin as practically possible.

Ceramic, tantalum, or aluminum electrolytic capac-

itors may be selected for CIN. There is no specific

capacitor ESR requirement for CIN; however, for

higher current operation, ceramic capacitors are

recommended for CIN due to their inherent capabil-

ity over tantalum capacitors to withstand input cur-

rent surges from low impedance sources, such as

batteries in portable devices.

Output Capacitor

For proper slew operation, a 0.1µF capacitor or

greater between VOUT and GND is recommended.

The output capacitor has no specific cap acitor type

or ESR requirement. If desired, COUT may be

increased without limit to accommodate any load

transient condition without adversely affecting the

device turn-on slew rate time.

Enable Function

The AAT4280A features an enable / disable func-

tion. This pin (ON/OFF) is compatible with both

TTL or CMOS logic.

Reverse Output-to-Input Voltage

Conditions and Protection

Under normal operating conditions, a parasitic

diode exists between the output and input of the

load switch. The input voltage should always

remain greater than the output load voltage main-

taining a reverse bias on the internal parasitic

diode. Conditions where VOUT might exceed VIN

should be avoided since this would forward bias

the internal parasitic diode and allow excessive

current flow into the VOUT pin and possible damage

to the load switch.

In applications where there is a possibility of VOUT

exceeding VIN for brief periods of time during normal

operation, the use of a larger value CIN capacitor is

highly recommended. A larger value of CIN with

respect to COUT will effect a slower CIN decay rate

during shutdown, thus preventing VOUT from

exceeding VIN. In applications where there is a

greater danger of VOUT exceeding VIN for extended

periods of time, it is recommended to place a

Schottky diode from VIN to VOUT (connecting the

cathode to VIN and anode to VOUT). The Schottky

diode forward voltage should be less than 0.45V.

Thermal Considerations and

High Output Current Applications

The AAT4280A is designed to deliver a continuous

output load current. The limiting characteristic for

maximum safe operating output load current is

package power dissipation. In order to obtain high

operating currents, careful device layout and circuit

operating conditions need to be taken into account.

The following discussions will assume the load

switch is mounted on a printed circuit board utiliz-

ing the minimum recommended footprint, as stated

in the layout considerations section.

At any given ambient temperature (TA), the maxi-

mum package power dissipation can be deter-

mined by the following equation:

PD(MAX) = [TJ(MAX) - TA] / ΘJA

Constants for the AAT4280A are maximum junction

temperature, TJ(MAX) = 125°C, and package thermal

resistance, ΘJA = 120°C/W. Worst case conditions

are calculated at the maximum operating tempera-

ture where TA= 85°C. Typical conditions are cal-

culated under normal ambient conditions where TA

= 25°C. At TA= 85°C, PD(MAX) = 333mW. At TA=

25°C, PD(MAX) = 833mW.

The maximum continuous output current for the

AAT4280A is a function of the package power dissi-

pation and the RDS of the MOSFET at TJ(MAX). The

maximum RDS of the MOSFET at TJ(MAX) is calcu-

lated by increasing the maximum room temperature

RDS by the RDS temperature coefficient. The tem-

perature coefficient (TC) is 2800ppm/°C. Therefore,

MAX RDS125°C = RDS25°C ×(1 + TC×∆T)

MAX RDS125°C = 120mΩ×(1 + 0.0028 ×

(125°C - 25°C)) = 154mΩ

AAT4280A

Slew Rate Controlled Load Switch

4280A.2004.11.1.0 11

For maximum current, refer to the following equation:

IOUT(MAX) < ( PD(MAX) / RDS)1/2

For example, if VIN = 5V, RDS(MAX)=154mΩand TA

= 25°C, IOUT(MAX) = 2.3A. If the output load current

were to exceed 2.3A or if the ambient temperature

were to increase, the internal die temperature

would increase and the device would be damaged.

Higher peak currents can be obtained with the

AAT4280A. To accomplish this, the device thermal

resistance must be reduced by increasing the heat

sink area or by operating the load switch in a duty

cycle manner.

High Peak Output Current Applications

Some applications require the load switch to oper-

ate at a continuous nominal current level with short

duration, high-current peaks. The duty cycle for

both output current levels must be taken into

account. To do so, first calculate the power dissi-

pation at the nominal continuous current level, and

then add in the additional power dissipation due to

the short duration, high-current peak scaled by the

duty factor.

For example, a 4V system using an AAT4280A

operates at a continuous 100mA load current level

and has short 2Acurrent peaks, as in a GSM appli-

cation. The current peak occurs for 576µs out of a

4.61ms period.

First, the current duty cycle is calculated:

% Peak Duty Cycle: X/100 = 576µs/4.61ms

% Peak Duty Cycle = 12.5%

The load current is 100mAfor 87.5% of the 4.61ms

period and 2A for 12.5% of the period. Since the

Electrical Characteristics do not report RDS(MAX) for

4V operation, it must be calculated approximately

by consulting the chart of RDS(ON) vs. VIN. The RDS

reported for 5V can be scaled by the ratio seen in

the chart to derive the RDS for a 4V VIN: 120mΩ×

87mΩ/80mΩ= 130mΩ. De-rated for temperature:

130mΩx (1 + .0028 ×(125°C -25°C)) = 166mΩ.

The power dissipation for a 100mAload is calculat-

ed as follows:

PD(MAX) = IOUT2×RDS

PD(100mA) = (100mA)2×166mΩ

PD(100mA) = 1.66mW

PD(87.5%D/C) = %DC ×PD(100mA)

PD(87.5%D/C) = 0.875 ×1.66mW

PD(87.5%D/C) = 1.45mW

The power dissipation for 100mA load at 87.5%

duty cycle is 1.45mW. Now the power dissipation

for the remaining 12.5% of the duty cycle at 2A is

calculated:

PD(MAX) = IOUT2×RDS

PD(2A) = (2A)2×166mΩ

PD(2A) = 664mW

PD(12.5%D/C) = %DC ×PD(2A)

PD(12.5%D/C) = 0.125 ×664mW

PD(12.5%D/C) = 83mW

The power dissipation for 2A load at 12.5% duty

cycle is 83mW. Finally, the two power figures are

summed to determine the total true power dissipa-

tion under the varied load:

PD(total) = PD(100mA) + PD(2A)

PD(total) = 1.45mW + 83mW

PD(total) = 84.5mW

The maximum power dissipation for the AAT4280A

operating at an ambient temperature of 85°C is

333mW. The device in this example will have a

total power dissipation of 84.5mW. This is well

within the thermal limits for safe operation of the

device; in fact, at 85°C, the AAT4280A will handle

a 2Apulse for up to 50% duty cycle. At lower ambi-

ent temperatures, the duty cycle can be further

increased.

AAT4280A

Slew Rate Controlled Load Switch

12 4280A.2004.11.1.0

Figure 1: Evaluation board Figure 2: Evaluation board Figure 3: Evaluation board

top side silk screen layout / component side layout solder side layout

assembly drawing

Printed Circuit Board

Layout Recommendations

For proper thermal management and to take

advantage of the low RDS(ON) of the AAT4280A, a

few circuit board layout rules should be followed:

VIN and VOUT should be routed using wider than

normal traces, and GND should be connected to a

ground plane. To maximize package thermal dis-

pation and power handling capacity of the

AAT4280ASOT23-6 and SC70JW-8 p ackages, the

ground plane area connected to the ground pins

should be made as large as possible. For best per-

formance, CIN and COUT should be placed close to

the package pins.

Evaluation Board Layout

The AAT4280A evaluation layout follows the print-

ed circuit board layout recommendations and can

be used for good applications layout. Refer to

Figures 1 through 3.

Note: Board layout shown is not to scale.

AAT4280A

Slew Rate Controlled Load Switch

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Ordering Information

Note: Sample stock is held for part numbers listed in BOLD.

Note 1: XYY = assembly and date code.

Package Information

SOT23-6

All dimensions in millimeters.

1.90 BSC

0.95 BSC

0.45 ± 0.15 0.10 BSC

2.85 ± 0.15

0.075 ± 0.075

0.40 ± 0.10 × 6

1.575

0.125

1.20

0.25

1.10

0.20 2.80

0.20

4°

10°

5°

0.15

0.07 GAUGE PLANE

0.60 REF

Device Option Package Marking1Part Number (Tape and Reel)

AAT4280A-1 SOT23-6 AAT4280AIGU-1-T1

AAT4280A-2 SOT23-6 AAT4280AIGU-2-T1

AAT4280A-3 SOT23-6 AAT4280AIGU-3-T1

AAT4280A-1 SC70JW-8 NDXYY AAT4280AIJS-1-T1

AAT4280A-2 SC70JW-8 NEXYY AAT4280AIJS-2-T1

AAT4280A-3 SC70JW-8 NFXYY AAT4280AIJS-3-T1

SC70JW-8

All dimensions in millimeters.

0.225 ± 0.075

0.45 ± 0.10

0.05 ± 0.05

2.10 ± 0.30

2.00 ± 0.20

7° ± 3°4° ± 4°

1.75 ± 0.10

0.85 ± 0.15

0.15 ± 0.05

1.10 MAX

0.100

2.20 ± 0.20

0.048REF

0.50 BSC 0.50 BSC 0.50 BSC

AAT4280A

Slew Rate Controlled Load Switch

14 4280A.2004.11.1.0

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830 E. Arques Avenue, Sunnyvale, CA 94085

Phone (408) 737-4600

Fax (408) 737-4611

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