SEMTECH SC310 Technical data

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1

POWER MANAGEMENT

SC310

High-Side Current-Sense Amplifier

with Low Impedance Voltage Output

Typical Application Circuit

Applications

Description

Features

The SC310 is a high-side current sense amplifier ideal for any application where precision current monitoring is needed. Possible uses include battery-powered products such as cellphones and notebooks, as well as industrial and data acquisition applications. The wide 2.7V to 25V common mode input range is independent of supply range, providing complete flexibility in battery sensing applications.

The Current-Sense Amplifier offers three gain versions, SC310A (gain 20 V/V), SC310B (gain 50 V/V) and SC310C (gain 100 V/V). An external shutdown pin (SHDN) enables turn off for the IC. A buffered output with low impedance renders the overall gain immune to load resistance. Output range is from 0V to Vcc - 1.7V.

Other features include tiny SOT-23-6 packaging, very low supply current, and wide supply voltage range (3V to 25V). The SC310 is rated for operation over the Industrial Temperature range (-40°C to +125°C).

 Three gain versions (20V/V, 50V/V, 100V/V)

available

 2.7V to 25V input common mode range  3V to 25V supply voltage range  270 μA supply current  1% typical accuracy  Buffered low impedance voltage output  Industrial temperature range (-40°C to +125°C)  Small, lead-free SOT23-6 Package

 Notebook and Tablet PCs  Data Acquisition  Battery Packs  Charging Applications  Industrial and Embedded Applications

June 4, 2007

0.1uF

2.7V to 25V

Load/

Battery

CS+

CS-

SHDN

OUT

GND

VCC

R

SENSE

I

LOAD

V

OUT

3V - 25V

0.1uF

2

POWER MANAGEMENT

SC310

Absolute Maximum Ratings

Electrical Characteristics

Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied.

V

CS+

= 2.7V to 25V, VCC = 3V to 25V, V

SENSE

= 0, TA = TJ = -40°C to +125°C , unless otherwise specified

retemaraPretemaraP

retemaraP

retemaraPretemaraPlobmySlobmyS

lobmyS

lobmySlobmySsnoitidnoCsnoitidnoC

snoitidnoC

snoitidnoCsnoitidnoCniMniM

niM

niMniMpyTpyT

pyT

pyTpyTxaMxaM

xaM

xaMxaMstinUstinU

stinU

stinUstinU

egnaRegatloVgnitarepOV

CC

352V

egnaRtupnIedoM-nommoCV

RMC

C°0 ≤ TA≤ C°521+7.252V

C°04- ≤ T

A

C°0<3 52

noitcejeRedoM-nommoCRMC09Bd

tnerruCylppuSI

CC

V

+SC

V,V7.2>

CC

V21=72.01Am

tnerruCsaiBtupnII

+SC

V

+SC

V7.2+>051Aμ

I

-SC

V

+SC

V7.2+>01

egatloVesneSelacS-lluFV

ESNES

V

ESNES

V=

+SC

V-

-SC

051Vm

rorrEegatloVTUOlatoTV

ESNES

V,Vm001+=

CC

,V21=

V

+SC

C°04-,V21= ≤ TA≤ C°58

152.4%

V

ESNES

V,Vm001+=

CC

,V21=

V

+SC

T,V21=

A

C°521=

15.4

V

ESNES

V,Vm001+=

CC

,V21=

V

+SC

T,V21+=

A

º52+=

152.3

V

ESNES

V,Vm001+=

CC

,V52=

V

+SC

C°04-,V52= ≤ TA≤ C°58

15.4

Parameter Symbol Min Max Units

Supply Voltage VCC -0.3 28 V Differe ntial Input Voltage V

CS+

- V

CS-

0.5 V

Thermal Resistance Junction

θ

JA

230 °C/W

Thermal Resistance Junction to Case

θ

JC

81 °C/W Operating Temperature Range TA -40 +125 °C Storage Temperature Range T

STG

-65 +150 °C Junction Temperature Range TJ -65 +150 °C Lead Temperature (Soldering) 10s T

LEAD

260 °C

CS+ Voltage V

CS+

-0.3 VCC + 0.3 V CS- Voltage V

CS-

-0.3 V C C + 0.3 V SHDN Voltage V

SHDN

-0.3 VCC + 0.3 V

ESD Rat ing (Huma n Body Mode l ) V

ESD

2 kV

3

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POWER MANAGEMENT

SC310

Electrical Characteristics (Cont.)

retemaraPretemaraP

retemaraP

retemaraPretemaraPlobmySlobmyS

lobmyS

lobmySlobmySsnoitidnoCsnoitidnoC

snoitidnoC

snoitidnoCsnoitidnoCniMniM

niM

niMniMpyTpyT

pyT

pyTpyTxaMxaM

xaM

xaMxaMstinUstinU

stinU

stinUstinU

rorrEegatloVTUOlatoTV

ESNES

V,Vm001+=

CC

,V52=

V

+SC

T,V52=

A

C°521=

157.4%

V

ESNES

V,Vm52.6+=

CC

=

V,V21

+SC

C°04-,V21= ≤

T

A

≤ C°521

5.7-/+

egatloVhgiHTUOV

CC

V-

HO

C°5- ≤ TA≤ C°521+7.1V

htdiwdnaBBd3WBV,A013CS

ESNES

Vm001+=2

V,B013CS

ESNES

Vm001+=4.1zHM

V,C013CS

ESNES

Vm001+=9.0

NIAGA

V

A013CS02V/V

B013CS05

C013CS001

ycaruccAniaGV

ESNES

,Vm001+=

C/B/A013CS

0.4%

ecnatsiseRtuptuOTUO

)1(

R

TUO

V

ESNES

Vm61+=06

Ω

noitcejeRylppuS-rewoPRRSPV

ESNES

Vm61=

V

+SC

V7.2+>

0607Bd

fo%1otemiTgniltteSTUO

eulaVlaniFeht

V

CC

V21+=

V

+SC

V21+=

C

DAOL

Fp5=

V

ESNES

=

Vm52.6+

ot

Vm001+

2Sμ

V

ESNES

=

Vm001+

ot

Vm52.6+

2

ehtfo%1otemiTpU-rewoP

eulaVlaniF

)2(

V

ESNES

,Vm001+=

C

DAOL

V,Fp5=

CC

V21+=

V

+SC

V21+=

05Sμ

NDHSroftnerrucsaibtupnII

NDHS

V

NDHS

V5+=7Aμ

V

NDHS

)noecived(dlohserhTV

NO_HT_NDHS

V3 ≤ Vcc≤ V52053Vm

V

NDHS

)ffoecived(dlohserhTV

FFO_HT_NDHS

V3 ≤ Vcc≤ V522 V

NDHSroftnerruCylppuSI

CC

V

cc

V,V21=

NDHS

V5+=11Aμ

Note (1): SC310 has a low impedence output. However the maximum output drive capability is limited to 500uA Note (2): Defined with respect to Shutdown signal. Time taken for output to go high as V

SHDN

switches from 5V to 0V

V

CS+

= 2.7V to 25V, VCC = 3V to 25V, V

SENSE

= 0, TA = TJ = -40°C to +125°C , unless otherwise specified

4

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SC310

3

1SHDN

TOP VIEW

(SOT-23 6L)

5 CS-

VCC

6

CS+4

OUT

2GND

Pin Configuration Ordering Information

eciveD

)3()2()1(

egakcaP

TRTKSX013CS6-32-TOS

BVEX013CSdraoBnoitaulavE

Pin Descriptions

niPemaNnoitcnuF

1NDHSCIehtelbaneotDNGottcennoC

2DNGdnuorG

3CCV roticapacFµ1.0ahtiwdnuorgotssapyb,tupnIegatloVylppuS

4+SCrotsiseresneslanretxeotnoitcennocedisrewoP

5-SCrotsiseresneslanretxeehtrofnoitcennocedisdaoL

6TUOV,tuptuoegatloV

TUO

Votlanoitroporpsi

ESNES

V(

+SC

V-

-SC

)

SC310A, gain = 20 V/V SC310B, gain = 50 V/V SC310C, gain = 100 V/V

Notes: (1) Where X denotes Gain options. Available Gains are: 20 V/V (A), 50 V/V (B), 100 V/V (C). Contact factory for additional voltage options. (2) Only available in tape and reel packaging. A reel contains 3000 devices. (3) This lead-free device is fully RoHS and WEEE compliant.

5

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SC310

Electrical Characteristics

T

V

CS+

= 12V, VCC = 12V, V

SENSE

= 100mV, TA = 25°C, unless otherwise specified

Supply Current

v/s Supply Voltage

0

0.1

0.2

0.3

0.4

0 5 10 15 20 25

Supply Voltage (V)

Supply Current (mA)

SC310B

SC310A

SC310C

Bias Current v/s

Common-Mode Voltage

100

110

120

130

140

150

0 5 10 15 20 25

Common-Mode Voltage (V)

Bias Current (uA)

SC310A

SC310B

SC310C

Total Output Voltage Error

v/s Supply Voltage

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25

Supply Voltage (V)

Total Output Error (%)

SC310A

SC310B

SC310C

Total Output Voltage Error

v/s Common-Mode Voltage

0.00

0.20

0.40

0.60

0.80

1.00

0 5 10 15 20 25

Common-Mode Voltage (V)

Total Output Error (%)

SC310C

SC310

A

SC310B

SC310A Gain Accuracy

with Temperature

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 40 80 120 160

Sense Voltage (mV)

Gain Accuracy (%)

-40 deg. C

+85 deg. C

Room Temp.

SC310B Gain Accuracy

with Temperature

0

0.2

0.4

0.6

0.8

1

1.2

0 40 80 120 160

Sense Voltage (mV)

Gain Accuracy (%)

Room Temp

+85 deg. C

-40 deg. C

6

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SC310

Electrical Characteristics

PSRR v/s Frequency

-9.0E+01

-7.0E+01

-5.0E+01

-3.0E+01

-1.0E+01

1.0E+01

1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+0 8

Frequency

PSRR (dB)

SC310CSC310B SC310A

Gain v/s Frequency

-4.00E+01

-2.00E+01

0.00E+00

2.00E+01

4.00E+01

6.00E+01

1.00E+011.00E+021.00E+031.00E+041.00E+051.00E+061.00E+071.00E+ 08

Frequency (Hz)

Gain (dB)

SC310B SC310A SC310C

V

CS+

= 12V, VCC = 12V, V

SENSE

= 100mV, TA = 25°C, unless otherwise specified

SC310C Gain Accuracy

with Temperature

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 40 80 120 160

Sense Voltage (mV)

Gain Accuracy (%)

-40 deg. C

Room Temp.

+85 deg. C

Bias Current v/s

Common-Mode Voltage in Shutdown

V

SHDN

= 5V

0

1

2

3

4

0 5 10 15 20 25

Common-Mode Voltage (V)

Bias Current (uA)

SC310B SC310A SC310C

Supply Current

v/s Supply Voltage in Shutdown

V

SHDN

= 5V

0

5

10

15

20

25

0 5 10 15 20 25

Supply Voltage (V)

Supply Current (uA)

SC310B SC310A SC310C

7

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SC310

Electrical Characteristics (Cont.)

V

CS+

= 12V, VCC = 12V, V

SENSE

= 100mV, TA = 25°C, unless otherwise specified

8

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SC310

Block Diagram

Detailed Description

SC310 is a unidirectional high-side current sense amplifier for precision current monitoring. It has a wide common-mode range of 2.7 to 25V and allows high-side current-sensing at voltages greater than supply voltage (VCC).

The SC310 operates as follows: Current from source (as shown in the typical applications circuit on page. 1), flows through RSENSE to the load. Since the inverting input of amplifier A has a high input impedance, negligible current flows through R5 (neglecting the input bias current). Amplifier A has an inverting input voltage which equals V(CS+) - I

LOAD*RSENSE

. The amplifier’s high open-loop gain forces the non-inverting input voltage to the same voltage as the inverting input. The drop across R4 equals I

LOAD*RSENSE

. Since IR4 flows through R4, IR4 =

(I

LOAD*RSENSE

)/R4. Resistor R3 then sets the overall gain for amplifier A, A1, A2 or A3 (neglecting the input bias currents for non-inverting inputs for amplifiers A and B). The second amplifier, B, is a fixed gain stage (gain = B) and the final output includes the gain obtained from this stage.

noisreVnoisreV

noisreV

noisreVnoisreVnoisserpxEniaGnoisserpxEniaG

noisserpxEniaG

noisserpxEniaGnoisserpxEniaGeulaVniaGeulaVniaG

eulaVniaG

eulaVniaGeulaVniaG

A013CSB*1A02

B013CSB*2A05

C013CSB*3A001

The SC310 has three gain versions as follows:

VCC

+

-

+

-

R1

R2

R3

R4

R5

Q1

A

B

Gain = A1 Gain = A2 Gain = A3

Gain = B

CS-

GND

SHDN

CS+

OUT

1k

10k

20k

5k

1k

Disable

9

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SC310

PCB trace can also be used as the sense resistor. This has the drawback of significant error at the output over temperature. The trade-off, despite the error in the output voltage, provides for a cost-effective solution.

SHDN FSHDN F

SHDN F

unctionunction

unction

The SHDN pin should not be kept floating and must be tied to either ground or be held high. Connecting the pin to ground is needed for normal operation. The voltage level at the SHDN pin is independent of the functioning of the IC.

TT

T

ypical Vypical V

ypical V

alues falues f

alues f

or Sense Ror Sense R

or Sense R

esistesist

esist

oror

or

ss

s

Table 1. lists the common resistor values for typical operation of the SC310. SC310 is capable of sensing wide ranges of currents providing proper sense resistors are used.

Output ImpedanceOutput Impedance

Output Impedance

The output impedance of the SC310 is very low. Typical

value is 60Ω. Connecting the OUT pin to a high-imped-

ance input stage is recommended. Resistive loading on the OUT pin will not affect the gain of the SC310.

Common Mode InputCommon Mode Input

Common Mode Input

The sense voltage is limited at low values of common mode input voltage (V

CMR

). The figure below specifies the desired sense voltage for low common mode input voltage. In the figure below we see that SC310A can be operated over full-scale sense voltage at Vcs+ = 2.7V, whereas the voltage is limited for SC310B and SC310C.

Layout GuidelinesLayout Guidelines

Layout Guidelines

1. Place the SC310 between the pins and external circuitry to reduce the trace length.

2. Place the decoupling capacitor at the input (V

CC

) as

close as possible to the pin.

3. An R-C filter at the input will help achieve the highest noise rejection.

4. Run the traces from R

SENSE

as close as possible. Use

minimum width traces to reduce capacitive coupling.

Choosing RChoosing R

Choosing R

sensesense

sense

Full scale sense voltage for the amplifier is 150mV max. The resistor (R

sense

) is selected depending on the load of

the system. For light loads a bigger value of R

sense

is selected to minimize the error in the proportional output voltage. Higher resistor value improves the strength of the signal at the current-sense amplifier input and hence gives an accurate output.

The voltage at the OUT pin of the amplifier is given as:

V

out

= (Gain) * (I

load

) * (R

sense

)

Similarly, for heavy loads, a smaller value of R

sense

resistor is used not to exceed the max “Sense Voltage” rating of the IC. Also at high loads, a power rating of R

sense

resistor is used and must be acceptable (greater than I2R power dissipation in the resistor).

Application Information

V

sense

0

70mV

150mV

2.7V

3.5V

28V

V

CS+

35mV

5V

SC310C

SC310B

SC310A

Not drawn to scale

10

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SC310

tnerruCdaoLelacS-lluFtnerruCdaoLelacS-lluF

tnerruCdaoLelacS-lluF

tnerruCdaoLelacS-lluFtnerruCdaoLelacS-lluF

IIIII

DAOLDAOL

DAOL

DAOLDAOL

)A()A(

)A(

)A()A(

RrotsiseResneStnerruCRrotsiseResneStnerruC

RrotsiseResneStnerruC

RrotsiseResneStnerruCRrotsiseResneStnerruC

esnesesnes

esnes

esnesesnes

m(m(

m(

m(m( ΩΩΩΩΩ))

)

))

niaGniaG

niaG

niaGniaG

egatloVtuptuOelacS-lluFegatloVtuptuOelacS-lluF

egatloVtuptuOelacS-lluF

egatloVtuptuOelacS-lluFegatloVtuptuOelacS-lluF

VelacS-lluF(VelacS-lluF(

VelacS-lluF(

VelacS-lluF(VelacS-lluF(

esnesesnes

esnes

esnesesnes

)Vm001=)Vm001=

)Vm001=

)Vm001=)Vm001=

VVVVV

tuotuo

tuo

tuotuo

)V()V(

)V(

)V()V(

1.00001

020.2

050.5

0010.01

1001

020.2

050.5

0010.01

205

020.2

050.5

0010.01

502

020.2

050.5

0010.01

0101

020.2

050.5

0010.01

Table 1. Recommended Component Values

11

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SC310

Outline Drawing - SOT-23-6

.110 BSC .037 BSC

DETAIL

aaa C

SEATING

ccc C

2X N/2 TIPS

2X

E/2

6

SEE DETAIL

A1

A

A2

bxN

A

.008

12

N

E

.060

.114 .063

.118

.010

-

6

A

0.20

1.60

3.00

2.80 BSC

0.95 BSC

.069 1.50

2.90

.020 0.25

1.75

0.50

-

EI

L

(L1)

c

01

0.25

PLANE

GAGE

H

2.80.110

bbb C A-B D

0°

.008

-

.004

.012

.003

(.024)

.018

-

.035

.000

.035

-

.045

0.10

0.20

10° 0°

-

10°

1.15

(0.60)

0.45.024

.009

0.30

0.08

.057

.051

.006 0.00

.90

0.90

0.22

0.60

-

0.15

1.45

1.30

-

1.90 BSC.075 BSC

A

e1

D

e

B

C

H

NOM

INCHES

DIMENSIONS

L1

aaa bbb

ccc

01

N

DIM

c

e

e1

L

E1

E

D

A1 A2

b

A

MIN

MILLIMETERS

MAX MIN NOM MAX

PLANE

D

DATUMS AND TO BE DETERMINED AT DATUM PLANE

CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).

DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS3. OR GATE BURRS.

NOTES:

1.

2. -A-

-B- -H-

SIDE VIEW

Land Pattern - SOT-23-6

THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET.

NOTES:

1.

DIMENSIONS

INCHES

Y

Z

DIM

G P X

C

MILLIMETERS

P

(C)

Z

Y

G

.043 .141

.055

(.098)

.037 .024

1.40

(2.50)

0.95

0.60

1.10

3.60

X

DIMENSIONS

INCHES

Y

Z

DIM

G P X

C

MILLIMETERS

12

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POWER MANAGEMENT

SC310

Table 1. Recommended Component Values

NOTES

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Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 FAX (805)498-3804

Contact Information

SEMTECH SC310 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual