Datasheet SC1462ISKTR Datasheet (Semtech Corporation)

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

DESCRIPTION

The SC1462 is a versatile charge pump designed for
use in battery operated power supply applications over
the wide input range of 1.65 to 5.5 volts. A simple, low
quiescent current charge pump doubler can be imple­mented without costly inductors or capacitors. Internal
MOSFETs and control circuitry eliminate the need for
costly board space and design time. The small 6 lead
SOT-23 package helps minimize board space.

The SC1462
tions that require up to 80mA of output current with V
= 2.5V to 5.5V. Typical dropout voltage (2*Vin-Vout) is
shown below for several values of Vin.

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Output Dropout Voltage (V)

0.1

0.0
000E+0 20E-3 40E-3 60E-3 80E-3 100E-3

charge pump can be used for applica-

Typical Dropout Voltage vs Iout

@Ta = 25 Deg. C.

Vin = 1.5V
Vin = 2.5V
Vin = 3.6V
Vin = 4.5V
Vin = 5.5V

Io u t (A)

FEATURES

•= Input supply voltage range of 1.65V to 5.5V

•= Small size - 6 pin SOT-23 package

•= Typical efficiency of :

91% @ Vin = 2.5V, Iout = 45mA
94% @ Vin = 3.6V, Iout = 55mA

•= Short circuit and over-temperature protection

•= 140µA typical input current @ no load

•= Shutdown current <1µA

•= Designed to work with ceramic or Tantalum

IN

capacitors

•= Fixed frequency of 160kHz

•= All specifications rated over full temperature

range (-40°C to 85°C)

APPLICATIONS

•= Cellular phones

•= Handheld devices

ORDERING INFORMATION

DEVICE

SC1462ISKTR SOT-23-6 -40°C to 85°C

Note:
(1) Only available in tape and reel packaging. A reel
contains 3000 devices.

(1)

PACKAGE Temp. Range (TA)

TYPICAL APPLICATION SCHEMATIC

1

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

ABSOLUTE MAXIMUM RATINGS

Parameter Symbol Maximum Units

Supply Voltage VIN -0.3 to +6.0 V
Output Voltage VO -0.3 to +12 V

Short Circuit Duration SC Indefinite

V

OUT

Thermal Resistance

θ

JA

230 °C/W

Junction to Ambient
Operating Ambient

T

A

-40 to +85 °C

Temperature Range
Junction Temperature Range T

Storage Temperature Range T
Lead Temperature

T

J

STG

L

-40 to +125 °C

-65 to +150 °C
300 °C

(Soldering) 10 seconds

ELECTRICAL CHARACTERISTICS

Unless specified: TA = -40°C to 85°C, SHDN = GND, 1.65V ≤ V

Parameter Symbol Conditions MIN TYP MAX Units

Input Supply Voltage V
Input Supply Current I

IN

IN

IO = 0, V

≤=5.5V, C

IN

= C

OUT

= C

IN

= 3.3µF (ESR = 0.3Ω).

BUCKET

1.65 5.5 V

= 2.5V freq = 160kHz 140 260 µA

IN

Output Resistance

Output Resistance

Total Switch Resistance

Total Switch Resistance

(5)

(5)

(6)

(6)

Output Current I

R

out

R

out

R

SW

R

SW

O

Oscillator Frequency OSC
Short Circuit Current I

Output Ripple (pk-pk)

Power Efficiency

(1)(3)

(1)

SC

V

R

η

= 0, V

I

O

= 3.6V freq = 160kHz 200 400 µA

IN

SHDN = V

V

IN

V

IN

V

IN

V

IN

V

IN

V

IN

≤ V

1.65V
V

out

IO = 45mA, V

Frequency = 160kHz

I

= 45mA,V

O

freq = 160kHz

IN

= 2.5V 9.5 13.5

= 3.6V 7.5 10.5

= 2.5V 3 4.5

= 3.6V 2 3

0.1 1 µA

Ω
Ω
Ω
Ω

= 2.5V 80 mA

= 3.6V 80 mA

≤=5.5V

IN

100 160 200 KHz

= 0V 200 mA

IN

IN

= 2.5V

= 2.5V

86 %

75 mV

2

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

ELECTRICAL CHARACTERISTICS

Unless specified: TA = -40°C to 85°C, SHDN = GND, 1.65V ≤ V

Parameter Symbol Conditions MIN TYP MAX Units

Maximum Output Voltage

Input High Threshold V

Input Low Threshold V

Time to Regulation at
Turn-on

Over Temperature
protection

Over Temperature
Hysteresis

(2)

(3)

(3)

(3)

V

OUT

ih

il

t

ON

SHDN pin, 2.5 ≤ VIN ≤ 5.5

SHDN pin, 2.5 ≤ VIN ≤ 5.5

IO = 0 to 60 mA, V

O.T. 140 °C

O.T.H 20 °C

NOTES:

(1) All electrical characteristics are for the application circuit on page 1.
(2) Soft start functionality is performed along with short circuit protection. If V
switches are turned off and V

is charged with a 200mA current source from VIN. When V

OUT

200mV all switches are enabled.
(3) Guaranteed by design.
(4) This device is ESD sensitive. Use of standard ESD handling precautions is required.
(5) The internal switch resistance, the capacitor ESR and the Oscillator’s switching frequency all contribute to
R
(6) The parameter R
section for information on applying the R

. See the CAPACITOR SELECTION section for information on applying the R

out

is equal to the total resistance of all 4 internal switches. See the CAPACITOR SELECTION

sw

sw

sistance and the equation on page 7 for R

≤=5.5V, C

IN

IO = 0mA 2*V

= C

OUT

= C

IN

= 3.3µF (ESR = 0.3Ω).

BUCKET

V

IN

1.6 V

0.4 V

= 3.6V

IN

500 µs

freq = 160kHz

is less than VIN - 200mV, then all

OUT

specification.

out

reaches VIN -

OUT

specification. This parameter was calculated from actual output re-

.

out

3

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

BLOCK DIAGRAM

PIN CONFIGURATION

(Top View)

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

6 Lead SOT-23

PIN DESCRIPTION

Pin #

SOT-23-6

1 VIN Supply voltage input.
2 GND Ground.
3 C- This pin should be connected to the negative terminal of the external charging

4 SHDN Shutdown pin. When this pin is connected to VIN, the device enters sleep mode.

5 VO Voltage output.
6 C+ This pin should be connected to the positive terminal of the external charging

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

Pin

Name

Pin Function

capacitor.

capacitor.

4

HIGH OUTPUT CURRENT

V

CHARGE PUMP DOUBLER

SC1462

October 20, 2000

VIN = 3V to 5.5

Cin

3.3uF

U1

SC1462

1

VIN

Vo

4 6

SHDN C+

GND

C-

2

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

5 Volts Fixed output Voltage

5

Cout

3.3uF

EN

3

Cbucket

3.3uF

U2
1
2
3 4

SC2982

VIN
GND
EN BYPASS

VOUT

5

C2

10nF

VOUT = 5V

C3
1uF

VIN = 2V to 3V

Cin

3.3uF

U1

SC1462

1

VIN

Vo

4 6

SHDN C+

GND

C-

2

3.3 Volts Fixed output Voltage

5

3

Cbucket

3.3uF

Cout

3.3uF

U2

1

3 4

EN

SC1453

IN

EN BYP

OUT

GND

2

5

C2

10nF

VOUT = 3.3V

C3
1uF

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

5

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

THEORY OF OPERATION

The SC1462 utilizes a switched capacitor charge
pump, to generate an output voltage approximately
2xVin.
An internal oscillator generates two out of phase
fixed frequency clock signals which turn on and off
internal MOSFET switches. During phase1 of clock,
the flying charge pump capacitor is charged to Vin
through switches S1, and S2. During phase2 the
flying charge pump capacitor is connected in ser ies
with the input voltage via S3, and S4, producing an
output voltage.

Charge transfer from Cin to C_charge

ON
S1,S2
OFF

ON
S3,S4
OFF

Charge transfer from (Cin,and C_charge) to Cout

OUTPUT CURRENT

The dropout voltage for a charge pump doubler is
defined as 2*Vin-Vout. The maxim um output current
is usually specified as that which will not cause the
dropout voltage to exceed the requirements of the
application. The calculation of the dropout voltage is
given in the capacitor selection section on page 7.
Typical dropout voltages versus Iout are graphed on
page 8.

THERMAL SHUTDOWN

The thermal shutdown circuit provides added protec­tion to the SC1462. During a V
tion or if the load is exc essive , the over temperature
circuitry will shut down the charge pump if the junction
temperature exceeds approximately 140°C. The
charge pump is enabled only if the junction tem pera­ture drops to approximately 120°C. The SC1462 will
cycle in and out of thermal shut down until the short
circuit or the excessive load condition on Vout is
removed, therby improving device reliability. The junc­tion temperature can be calculated fr om the f ollowing
formula if the ambient temperature (Ta) and the
charge pump power dissipation (Pdiss) are known.

short circuit condi-

OUT

S1 S4

C1+

CoutC_charge

C1-

Vout

S3 S2

Vin

Gnd

Cin

Gnd

SHORT CIRCUIT / SOFT START

An internal current limit and soft start circuit provides
protection against output short c ircuit and lim its large
current spikes generated during the initial start up to
charge output capacitor.

is less than VIN - 200mV, then all switches ar e

If V

OUT

turned off and V
source from V
the current source is disconnected from output and
the charge pump circuitry is enabled again.

is charged with a 200mA c urrent

OUT

. When V

IN

reaches VIN - 200mV ,

OUT

= Ta + P

T

J

* θJA ; θJA = 230 °C/W

diss

6

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

CAPACITOR SELECTION

Capacitor selection is based on both the maximum
acceptable ripple voltage and the maxim um toler able
drop at the output.

Ripple
The peak to peak output ripple voltage is dependent

on the following factors:
1- Oscillator Frequency

2- ESR of C
3- Capacitance value of C

Item 1 is fixed and depend on the charge pump de­vice used. Item 2, and 3 can be optimized for best
performance and reduction of the output ripple.

The following form ula could be used for an approxi­mation for V

V +=

out_ripple

Vout Drop

OUT

out_ripple

I

out

out

.

C ESR_x Ix 2

Cx Fx 2

outosc

outout

LAYOUT CONSIDERATION

Standard power board layout should followed to en­sure proper operation. Any stray inductance should
be minimized, this can be achieved by using large
power planes or traces, and reducing the distances
between input, output and the load. All components
should be placed as close as possible to the SC1462.

Following tables show typical capacitor characteris­tics, and capacitor manufactures.

Component ESR

(Ohms)

0.1 uF Ceramic 0603 package 0.050 1.60

1.0 uF Ceramic 1206 package 0.040 0.47
10 uF Ceramic 1206 package 0.075 0.5
47 uF, 16V Tantalum D case 0.100 0.60
330 uF, 6.3V “OSCON” 0.025 2.5
330 uF, 16V Al Electrolytic 0.143 2.37
820 uF, 4.0V “OSCON” 0.012 2.5
1000 uF, 10V Al Electrolytic 0.053 5

ESL
(nH)

The voltage drop at the output is specified with the
following equation:

Vout_drop = Iout * Rout
Rout is dependent on the following factors:
1- Oscillator Frequency

2- ESR of C
3- Capacitance value of C

OUT

& C

bucket

OUT

& C

bucket

4- Internal switch resistance (Rsw = Total of all 4
switch resistances).

A good approximation for calculating the output resis­tance is shown below.

R +×+×+≅

out

1

Cx F

bucketosc

C ESR_ C ESR_4 R2

outbucketSW

This equation can be used to c alculate Cbuc ket f or a
specific Vout when Vin and Iout are known. The
maximum value for the Rsw from the Electric al Char ­acteristics section on page 2 should be used in or der
to find a worst case number.

Capacitor Manufacturers Phone

AVX Corp. (803)-448-9411
VISHAY (207)-324-4140
Nichicon Corp. (708)-843-7500
muRata (800)-831-9172
TOKIN (408)-432-8020
Taiyo Yuden (800)-348-2496
Sanyo (619)-661-6835

7

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

Ty pic al Iin vs V in @ Ta = 25 D eg. C.

700E-6

600E-6

500E-6

400E-6

300E-6

Iin (A)

200E-6

100E-6

000E+0

1.0 2.0 3.0 4.0 5.0 6.0

900E-6

800E-6

700E-6

600E-6

500E-6

400E-6

Iin (A)

300E-6

200E-6

100E-6

000E+0

Vin = 5.5V
Vin = 4.5V
Vin = 3.6V
Vin = 2.5V
Vin = 1.5V

-40 -20 0 20 40 60 80

Vin (V)

Typical Iin vs Ta @ Io = 0mA

Ta (De g . C.)

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

Typical Dropout Voltage vs Iout

@Ta = 25 Deg. C.

Io u t (A)

Typical Dropout Voltage vs Ta

T a (Deg . C.)

Io = 0m A

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

Outp ut Dropo ut Voltage (V)

0.1

0.0
000E+0 20E-3 40E-3 60E-3 80E-3 100E-3

550E-3

500E-3

450E-3

400E-3

350E-3

Output Dropout Voltage (V)

300E-3

Vin = 1.5V
Vin = 2.5V
Vin = 3.6V
Vin = 4.5V
Vin = 5.5V

Vin = 2.5V, Iout = 50mA

Vin = 3.6V, Iout = 60mA

-40-200 20406080

Typical Efficiency vs Iou t

@Ta = 25 Deg. C.

100%

96%

Vout Ripple

50mV/Div.

92%

88%

Efficiency (%)

84%

80%

000E+0 20E-3 40E-3 60E-3 80E-3 100E-3

Vin = 5.5V
Vin = 4.5V
Vin = 3.6V
Vin = 2.5V
Vin = 1.5V

Vin = 3.6V
Iout = 60mA
Cin = Cout = Cbucket =3.3uF

Iou t (A)

8

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH OUTPUT CURRENT
CHARGE PUMP DOUBLER

SC1462

October 20, 2000

DEVICE OUTLINE - SOT23-6L

TEL:[phone] FAX:[phone] WEB:http://www.semtech.com

MINIMUM LAND PATTERN - SOT23-6L

ECN00-1344

9

© 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320