ST ST890 User Manual

1.2 A current limited high side power switch

Features

■ 2.7 V to 5.5 V input range

■ Programmable current limit up to 1.2 A

■ Low quiescent current

■ Thermal shutdown

■ Active low FAULT indicator output

■ 90 mΩ (typ.) ON resistance

■ SO-8 and DFN8L (3 x 3 mm) packages

ST890

with thermal shutdown

SO-8

DFN8L

(3x3mm)

Description

Applications

■ PCMCIA slots

■ Access bus slots

■ Portable equipment

Table 1. Device summary

Order code Package Packaging

ST890BDR SO-8 2500 parts per reel

ST890CDR SO-8 2500 parts per reel

The ST890 is a low voltage, P-channel MOSFET
power switch intended for high side load switching
applications.

The switch operates with inputs from 2.7 V to

5.5 V, making it ideal for both 3 V and 5 V
systems.

The internal current limiting circuitry protects the
input supply against overload. The thermal
overload protection limits power dissipation and
junction temperatures.

The maximum current limit is 1.2 A. The current
limit through the switch is programmed with a
resistor from SET to ground. The devices are
available in SO-8 and DFN8L (3 x 3 mm)
packages.

ST890DTR DFN8L (3 x 3 mm) 3000 parts per reel

March 2009 Rev 8 1/20

www.st.com

20

Contents ST890

Contents

1 Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.1 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.1 Output current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.2 Output short circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.3 Programming ILIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.4 Fault pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.5 Thermal protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2/20

ST890 Device summary

1 Device summary

Figure 1. SO-8 pin connection (top view)

1

IN

2

IN

3

ON

4

GND

Table 2. SO-8 pin description

Pin N. Symbol Name and function

8

7

6

5

FAULT

OUT

OUT

SET

CS07570

1, 2 IN

3ON

4 GND Ground

5 SET

6,7 OUT

8FAULT

Input P-channel MOSFET source. Bypass IN with a 1 μF
capacitor to ground

Active low switch ON input. A logic low turns the switch ON

Set current limit input. A resistor from SET to GND sets the
current limit for the switch. R
I

is the desired current limit in Amperes

LIM

Switch output. P-channel MOSFET drain. Bypass OUT with
a 0.1 μF capacitor to ground

Fault indicator output. This open drain output goes low
when in current limit or when the die temperature exceeds
135°C

= 1.24x1110/ I

SET

LIM

, where

3/20

Device summary ST890

Figure 2. DFN8L (3 x 3 mm) pin connection (top view)

IN

1

IN

2

ON

3

GND

Table 3. DFN8L (3 x 3 mm) pin description

8

7

6

5

FAULT

OUT

OUT

SET

Pin N. Symbol Name and function

1, 2 IN

3ON

Input P-channel MOSFET source. Bypass IN with a 1 μF
capacitor to ground

Active low switch ON input. A logic low turns the switch ON

4 GND Ground

5 SET

Set current limit input. A resistor from SET to GND sets the
current limit for the switch.

Switch output. P-channel MOSFET drain. Bypass OUT with

6,7 OUT

a 0.1 μF capacitor to ground.
R

= 1.24x1110/I

SET

, where I

LIM

limit in Amperes

Fault indicator output. This open drain output goes low

8FAULT

when in current limit or when the die temperature exceeds
135 °C

is the desired current

LIM

CS00025

4/20

ST890 Device summary

Figure 3. Schematic diagram

IN

/FAULT

/ON

Control

circuitry

­ON

+

ON

-

Current limit

amplifie r

+

Replica

amplifier

OUT

SET

1.24V

GND

CS00026

Table 4. Truth table for ON/OFF switch

ON/OFF OUT

LON

HOFF

Table 5. Truth t a b l e fo r FAULT

FAULT FLAG

H Normal operation

L Fault condition

5/20

Maximum rating ST890

2 Maximum rating

Stressing the device above the rating listed in the “Absolute maximum ratings” table may
cause permanent damage to the device. These are stress ratings only and operation of the
device at these or any other conditions above those indicated in the operating sections of
this specification is not implied. Exposure to Absolute maximum rating conditions for
extended periods may affect device reliability. Refer also to the STMicroelectronics SURE
Program and other relevant quality documents.

Table 6. Absolute maximum ratings

Symbol Parameter Value Unit

V

I

V

ON

V

FAU LT _N

V

SET

I

DS

T

stg

T

op

Table 7. Thermal data

Supply voltage -0.5 to +6 V

Input voltage at ON pin -0.5 to +6 V

Input voltage at FAULT_N pin -0.5 to +6 V

Voltage at SET pin -0.5 to (VIN +0.5) V

Maximum continuous switching current 1.5 A

Storage temperature -65 to +150 °C

Operating ambient temperature range -40 to +85 °C

Symbol Parameter SO-8 DFN8L Unit

R

thj-amb

Thermal

resistance

160

(1)

37.6

(2)

junction-ambient

1. This value depends from thermal design of PCB on which the device is mounted.

2. This value depends from the 4-layer PCB, JEDEC standard test board.

Table 8. Electrical characteristics

Val ue

Symbol Parameter

Test condition

(1)

Min Typ Max

T

= 25°C

A

°C/W

Unit

V

I

CC

Operating voltage ID=1mA 2.7 5.5 V

I

=5V,

V

ON quiescent
supply current

I

= GND

ON
IO = 0

ON =IN
V

I=VOUT

ON

=IN

=5.5V

V

I

V

=0

O

I

(CCOFF)

OFF quiescent
supply current

6/20

=5.5V

13 25 μA

1

μA

5

ST890 Maximum rating

Table 8. Electrical characteristics (continued)

Val ue

Symbol Parameter

V

ULO

Undervoltage
lockout

Test condition

(1)

Min Typ Max

Rising edge 2.0 2.4 2.6

T

= 25°C

A

Unit

V

V

HYST

R

ON

V

SET

I

MAX

I

SC

I

LIM/ISET

V

IL

V

IH

I

I

Undervoltage
lockout hysteresis

ON resistance

Reference voltage
to turn the switch
OFF

Maximum
programmable
output over
current limit

Short circuit
current limit

I

to I

SET

current

LIM

ratio

ON input low level
voltage

ON input high
level voltage

ON input leakage
current

100

V

= 4.5 V 75 120 mΩ

I

V

= 3 V 90 130 mΩ

I

= 100 mA

I

O

rise until VI-VO>

V

SET

1.178 1.24 1.302

0.8V

1.2

VI = 5V, OUT connected
to GND, device enabled

1.2 I

LIM

1.5 I

LIM

into short circuit

=500mA

I

O

VO>1.6V

= 2.7 to 5.5 V 0.8 V

V

I

= 2.7 to 3.6 V 2.0 V

V

I

V

= 2.7 to 5.5 V 2.4 V

I

V

=5.5V 1 μA

I

970 1110 1300

mV

V

A

A

I

bias I

SET

V

OL

I

OH

T

PROT

T

HYST

1. VIN=3V, TA=T

SET

FAULT output low
voltage

FAULT output high
voltage

Thermal
protection

Thermal
hysteresis

bias current

to T

MIN

MAX

V

=1.24V

SET

IO=0A
V

I=VO

=1 mA

I

SINK

V

= 1.4 V

SET

V

FAU LT

=1V

V

SET

=5.5V

0.5 3 μA

0.15 V

130 °C

15 °C

, unless otherwise specified. Typical values are at TA=25°C

7/20

1 μA

Maximum rating ST890

/FAU

G

/O

S

OUTPUT

Table 9. Timing characteristics

Val ue

Symbol Parameter Test condition

t

RESP

Slow current loop
response time

Fast current loop

20% current overdrive,

=5 V

V

CC

response time

V

=5 V

I

IO = 500 mA

t

ON

Turn ON time

V

=3V

I

IO = 500 mA

t

OFF

1. VIN=3V, TA=T

Turn OFF time VI=5V 1 2 10 μs

to T

MIN

, unless otherwise specified. Typical values are at TA = 25 °C

MAX

Figure 4. Typical application circuit

INPUT

100 k Ω

LT

1μ F

ND

(1)

= 25°C

A

Min Typ Max

N

ET

ON/OFF

UnitT

5 μs

2 μs

25 50 μs

50 μs

0.1μ F

8/20

R

SET

CS00027

ST890 Maximum rating

2.1 Functional description

2.1.1 Output current limit

I

is the output current that ST890 limits under the condition VO (output voltage) > 1.6 V.

LIM

When I

2.1.2 Output short circuit protection

The ST890 provides short circuit protection by limiting the output current during a short
circuit event.

I

is the output short circuit current limit level (typ 1.2 x I

sc

such as V

When the output is short circuit, the Fault pin is asserted.

is reached, the Fault pin is asserted.

LIM

). When the output is short circuit

< 1.6 V, the ST890 limits the output current to no more than the Isc level.

O

LIM

2.1.3 Programming I

The ST890's I
SET pin (pin 5).

I

is determined by the following relationships:

LIM

Equation 1

Equation 2

therefore:

Equation 3

can be programmed through the external resistor, R

LIM

2.1.4 Fault pin

The Fault pin (pin 8) is an open drain active low output. This pin should be connected to an
external pull-up resistor.

LIM

connected at the

SET

R / V = I

SETSETSET

1110 = I / I

SETLIM

I / 1110x 1.24 = R

LIMSET

The Fault pin is asserted low when:

–I

reaches the programmed I

OUT

– A short circuit event occurs

– The device goes into thermal protection

2.1.5 Thermal protection

The ST890's thermal protection is triggered to turn off the switch when the junction
temperature exceeds 130°C (typ).

value

LIM

9/20

Maximum rating ST890

2.2 Typical performance characteristics

Unless otherwise specified Tj = 25 °C.

Figure 5. ON resistance vs. supply voltage

Figure 6. ON resistance vs. temperature

10/20

ST890 Maximum rating

Ω

Ω

Figure 7. Switching waveforms

VCC=5V, RL=0.6

VCC=5V, RL=0.32

11/20

Package mechanical data ST890

3 Package mechanical data

In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.

Figure 8. SO-8 package drawing

1. Drawing not to scale.

0016023/C

12/20

ST890 Package mechanical data

Table 10. SO-8 package mechanical data

millimeters inches

Symbol

Min Typ Max Min Typ Max

A 1.35 1.75 0.053 0.069

A1 0.10 0.25 0.04 0.010

A2 1.10 1.65 0.043 0.065

B 0.33 0.51 0.013 0.020

C 0.19 0.25 0.007 0.010

D 4.80 5.00 0.189 0.197

E 3.80 4.00 0.150 0.157

e 1.27 0.050

H 5.80 6.20 0.228 0.244

h 0.25 0.50 0.010 0.020

L 0.40 1.27 0.016 0.050

k8°(max)

ddd 0.1 0.04

13/20

Package mechanical data ST890

Figure 9. SO-8 tape and reel specifications

1. Drawing not to scale.

Table 11. SO-8 tape and reel mechanical data

millimeters inches

Symbol

Min Typ Max Min Typ Max

A 330 12.992

C 12.8 13.2 0.504 0.519

D 20.2 0.795

N60 2.362

T22.40.882

Ao 8.1 8.5 0.319 0.335

Bo 5.5 5.9 0.216 0.232

Ko 2.1 2.3 0.082 0.090

Po 3.9 4.1 0.153 0.161

P 7.9 8.1 0.311 0.319

14/20

ST890 Package mechanical data

Figure 10. DFN8L (3 x 3 mm) package drawing

1. Drawing is not to scale.

2. Dimensions in millimeters.

PO8092726_A

15/20

Package mechanical data ST890

Table 12. DFN8L (3 x 3 mm) package mechanical data

millimeters

Symbol

Min Typ Max

A 0.80 0.85 0.90

A1 0 0.02 0.05

b 0.25 0.030 0.35

D 2.95 3 3.05

D2 2.30 2.40 2.50

E 2.95 3 3.05

E2 1.70 1.80 1.90

e0.65

L 0.25 0.30 0.35

Figure 11. DFN8L (3 x 3 mm) footprint recommendations

1. Drawing not to scale.

2. Dimensions in millimeters.

16/20

FR8092726_A

ST890 Package mechanical data

Figure 12. DFN8L (3 x 3 mm) tape and reel specifications

17/20

Package mechanical data ST890

Figure 13. DFN8L (3 x 3 mm) reel specifications

18/20

ST890 Revision history

4 Revision history

Table 13. Document revision history

Date Revision Changes

22-Jul-2005 4 Added 3 rows on Table 2 on page 3

10-Aug-2007 5

1-Dec-2007 6

13-Oct-2008 7

04-Mar-2009 8

Removed ST890CD and ST890BD from Table 1 on page 1
Updated short circuit current limit value in Table 8 on page 6

Added Section : Contents.
Added ST890D and related DFN8L package information.
Added Figure 2: DFN8L (3 x 3 mm) pin connection (top view) on

page 4.
Figure 3: Schematic diagram on page 5: redrawn, no content

change.
Modified title in Table 5: Truth table for FAULT on page 5.
Updated Table 8: Electrical characteristics on page 6.

Figure 4: Typical application circuit on page 8: redrawn, no content

change.

Updated: Table 2 on page 3, Table 3 on page 4.
Added: Section 2.1: Functional description on page 9 and Figure 12

on page 17.

Replaced ST890B, ST890C and ST890D with ST890.
Modified: Table 6: Absolute maximum ratings

19/20

ST890

Please Read Carefully:

Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the
right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any
time, without notice.

All ST products are sold pursuant to ST’s terms and conditions of sale.

Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no
liability whatsoever relating to the choice, selection or use of the ST products and services described herein.

No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this
document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products
or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such
third party products or services or any intellectual property contained therein.

UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED
WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS
OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT.

UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT
RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING
APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY,
DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE
GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK.

Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void
any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any
liability of ST.

ST and the ST logo are trademarks or registered trademarks of ST in various countries.

Information in this document supersedes and replaces all information previously supplied.

The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners.

© 2009 STMicroelectronics - All rights reserved

STMicroelectronics group of companies

Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan -

Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America

www.st.com

20/20