Datasheet SC1517ISK-5.TR Datasheet (Semtech Corporation)

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

October 3, 2000

The SC1517-5 is pin compatible with LTC1517-5. This
versatile charge pump produces a regulated 5V output
from an input voltage ranging from 2.7V to 5V. The
Extremely low operating current (typically 10µA with no
load) prolongs battery usage time. The small device
footprint and the low external parts count (one 0.1µF
flying capacitor and two small bypass capacitors at V
and V
circuit design.

The SC1517-5 charge pump can be used for
applications that require up to 20mA (3V <
output current, while providing a regulated 5V output
voltage. During short circuit a current limit circuitry
provides protection, while the thermal shutdown
capability cycles V
SC1517-5 is available in a 5 lead SOT-23 package.

) make the part ideally suited for compact

OUT

to prevent device failure. The

OUT

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

VIN < 5V) of

FEATURESDESCRIPTION

Ultra low power: I

•=

= 10µA typ

CC

•= Soft start / Short circuit Current limit

•= Thermal protected

•= 5V+ 4% Regulated output

•= V

Range: 2.7V to 5V

IN

•= Output current:

IN

10mA (V
20mA (V

> 2.7V)

IN

> 3V)

IN

•= No inductors

•= Ultra small application circuit

•= 800kHz switching frequency

•= Surface mount packaging (5 pin SOT-23)

•= All specifications rated over full temperature range

(-40°C to 85°C)

APPLICATIONS

•= Cellular telephones

•= Battery-operated equipment

•= Local power supplies

•= Handheld instruments

•= PCMCIA supplies

TYPICAL APPLICATION SCHEMATIC

C1 =

CIN = = COUT

ORDERING INFORMATION

Device

SC1517ISK-5.TR SOT-23-5 -40° to 85°C

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

(1)

Package Temp. Range (TA)

Note :

Ceramic capacitors used for improved performance, Low ESR Tantalum with ESR < 0.5 Ohms could also be used.

1

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

MICROPOWER, REGULATED 5V

SC1517-5

CHARGE PUMP

October 3, 2000

ABSOLUTE MAXIMUM RATINGS

Parameter Symbol Maximum Units

Input Supply Voltage V
Output Supply Voltage V
Power Dissipation P
Thermal Resistance

θ

Operating Ambient

in

out

d

JA

T

A

-0.3 to 6 V

-0.3 to 6 V
391 mW
256 °C/W

-40 to +85 °C

Temperature Range
Operating Junction

T

J

-40 to +125 °C

Temperature Range
Storage Temperature Range T

Lead Temperature

T

STG

LEAD

-65 to +150 °C
+300 °C

(Soldering) 10 Sec
ESD Rating (Human Body Model) ESD 2 kV

ELECTRICAL CHARACTERISTICS

Unless specified: TA = -40°C to 85°C, VIN = 2.7V to 5V, C1 = 0.1µF, CIN = 3.3µF, C

Parameter Symbol Conditions Min Typ Max Units

Operating Input Voltage V
Output Voltage V

Input Supply Current I
V

Ripple (pk-pk)

OUT

Oscillator Frequency
V

Turn-On Time

OUT

Soft start / Short circuit
Current limit

(1)(2)

(1)(2)

(1)(2)

(1)(2)(3)

f

I

OUT

CC

V

OSC

t

ON

limit

IN

2.7V < V
3V <

2.7V < V

R

VIN = 3V, I

< 5V, I

IN

VIN < 5V, I

< 5V, I

IN

= 20mA, C

OUT

V

= 3V, I

IN

< 10mA 4.8 5.0 5.2 V

OUT

< 20mA 4.8 5.0 5.2 V

OUT

= 0 10 15 µA

OUT

= 6.8µF 75 mV

OUT

= 0mA 1 ms

OUT

Short circuit applied at Vout to GND 35 65 mA

= 6.8µF.

OUT

2.7 5 V

800 kHz

P-P

NOTES:

(1) All electrical characteristics are for the application circuit on page 1.
(2) Guaranteed by design.
(3) Indefinite duration.

2

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

October 3, 2000

BLOCK DIAGRAM

PIN CONFIGURATION

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

Top View

SOT-23-5L

PIN DESCRIPTION

Pin # Pin Name Description

1 VIN Charge pump input voltage. May be between 2.7V and 5V. V

bypassed with a >

for best performance.
2 GND Ground pin.
3 VOUT Regulated output voltage. V

ESR capacitor as close as possible to the pin for best performance.
4 C1+ Charge pump flying capacitor positive terminal.

3.3µF low ESR capacitor as close as possible to the pin

should be bypassed with a > 3.3µF low

OUT

should be

IN

5 C1- Charge pump flying capacitor negative terminal.

3

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

October 3, 2000

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

Typical Eff. vs Iout (Ta = 25 Deg. C.)

100%

90%
80%
70%
60%
50%
40%

Efficiency (%)

30%
20%
10%

0%

10.0E-6 100.0E-6 1.0E-3 10.0E-3 100.0E-3

Vin = 2.75 V
Vin = 3.85 V
Vin = 5.00 V

Iout (A)

Typical Eff. vs Vin (Ta = 25 Deg. C.)

100%

90%
80%
70%
60%
50%
40%

Efficiency (%)

30%
20%
10%

0%

2.50 3.00 3.50 4.00 4.50 5.00 5.50

Iout = 20mA
Iout = 10mA
Iout = 5mA
Iout = 200uA
Iout = 10uA

Vin (V)

150.0E-3

130.0E-3

110.0E-3

90.0E-3

Vout (V)

70.0E-3

50.0E-3

30.0E-3

Typical Output ripple vs Vin ( Ta = 25 Deg. C.)

Cout = 3.3uF
Cout = 6.8uF

Iout = 10mA

2.50 3.00 3.50 4.00 4.50 5.00 5.50

Vin (V)

Cout = 10uF
Cout = 22uF

Typical Iin vs Io u t ( Ta = 2 5 D e g. C .)

50.0E-3

45.0E-3

40.0E-3

35.0E-3

30.0E-3

25.0E-3

Iin (A)

20.0E-3

15.0E-3

10.0E-3

5.0E-3

000.0E+0

000.0E+05.0E-3 10.0E-3 15.0E-3 20.0E-3 25.0E-3

Iout (A)

Vin = 2.75 V
Vin = 3.85 V
Vin = 5.00 V

4

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

October 3, 2000

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

Typical Iin v s Ta (Iout = 0 A )

14.0E-6

13.0E-6

12.0E-6

11.0E-6

Iin (A)

10.0E-6

9.0E-6

8.0E-6
0 10203040506070

Ta (Deg. C.)

Vin = 5.00 V
Vin = 3.85 V
Vin = 2.75 V

Typical Eff. vs Ta (Iout = 10 uA)

70%
60%
50%
40%
30%

Efficiency (%)

20%
10%

0%

0 10203040506070

Ta (Deg. C.)

Vin = 2.75 V
Vin = 3.85 V
Vin = 5.00 V

Typical Eff. vs Ta (Iout = 5 mA)

100%

90%
80%
70%
60%
50%
40%

Efficiency (%)

30%
20%
10%

0%

0 10203040506070

Ta (Deg. C .)

Vin = 2.75 V
Vin = 3.85 V
Vin = 5.00 V

Typical Eff. vs Ta (Iout = 10 mA)

100%

90%
80%
70%
60%
50%
40%

Efficiency (%)

30%
20%
10%

0%

010203040506070

Ta (Deg. C.)

Vin = 2.75 V
Vin = 3.85 V
Vin = 5.00 V

Typical Eff. vs Ta (Iout = 200 uA)

90%
80%
70%
60%
50%
40%
30%

Efficiency (%)

20%
10%

0%

0 10203040506070

Ta (Deg. C.)

Vin = 2. 75 V
Vin = 3. 85 V
Vin = 5. 00 V

Efficiency (%)

100%

90%
80%
70%
60%
50%
40%
30%
20%
10%

0%

Typical Eff. vs Ta (Iout = 20 mA)

Vin = 2. 75 V
Vin = 3. 85 V
Vin = 5. 00 V

010203040506070

Ta (Deg. C.)

5

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

October 3, 2000

5.00

4.95

4.90

Vout (V)

4.85

4.80

2.50 3.00 3.50 4.00 4.50 5.00 5.50

Typical Vout vs Vin (Iout = 10mA)

Ta = 70 Deg. C.
Ta = 25 Deg. C.
Ta = 0 Deg. C.

Vin (V)

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

6

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

October 3, 2000

Turn on Regulation time(Ta = 25 Deg. C.)

MICROPOWER, REGULATED 5V
CHARGE PUMP

Vout

2V/div.

Vin = 3V

2V/div.

SC1517-5

Load Transient Response(Ta = 25 Deg. C.)

Vout

50mV/div.

Iout Step
0 -10 ma

Vin = 3.0V

7

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

October 3, 2000

APPLICATION NOTES

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

THEORY OF OPERATION

The SC1517-5 utilizes a switched capacitor charge
pump, to generate an output voltage regulated to 5V+/­4%.

Current Limit

&

Soft Start

An internal oscillator generates two out of phas e clock
signals which turn on and off internal MOSFET
switches. During phase1 of clock, the flying charge

Charge transfer from Cin to C_charge

ON
S1,S2
OFF

ON
S3,S4
OFF

Charge transfer from (Cin,and C_charge) to Cout

pump capacitor is charged to Vin through switches S1,
and S2. During phase2 the flying charge pump
capacitor is connected in series with the input voltage
via S3, and S4, producing an output voltage.
An integrated comparator senses the output voltage

S1 S4

C1+

CoutC_charge

C1-

Vout

S3 S2

Vin

Cin

and disable the charge pump onc e an upper threshold
is reached. As the output voltage drops below the lower
threshold, the comparator enables the charge pump
and hence regulation is achieved.

SHORT CIRCUIT / SOFT START

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

As the over current condition is applied at the output, a
comparator senses the output voltage and com pares it
to a signal approximating V

< V

If V

OUT

- 500mV, the compar ator enables a 65mA

IN

- 500mV.

IN

typical limited current source and the c harge pump is
disabled. Once the over current is removed and

> V

V

OUT

- 500mV, the current s ource is dis connected

IN

from output and the charge pump circuitry is enabled
again.

THERMAL SHUTDOWN

The thermal shutdown circuit provides added protection
to the SC1517-5. During a V
if the load is excessive (I
shut down circuit is active and if the junction
temperature exceeds approx imately 160°C, the charge
pump is disabled. The charge pum p is enabled only if
the junction temperature drops to approximately 145°C.
The SC1517-5 will cycle in and out of thermal shut
down until the short circuit or the excessive load
condition on V

is removed, thereby improving device

OUT

reliability.

V

RIPPLE & CAPACITOR SELECTION

OUT

The peak to peak output ripple voltage is dependent on
the following factors:

1- Oscillator Frequency
2- Hysteresis window of the comparator
3- ESR of C

Charge

, and C

4- Capacitance value of C
Item 1, and 2 are fixed and depend on the charge

pump device used. Item 3, and 4 can be optimized for
best performance and reduction of the output ripple.

short circuit condition or

OUT

> = 20mA), the thermal

OUT

out

, and C

out

Charge

Gnd

Gnd

8

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

October 3, 2000

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

The following formula could be used for an
approximation for V

V +=

out_ripple

out_ripple

I

out

.

C ESR_x I

Cx Fx 2

outosc

outout

Figure below shows the effect of output capacitance
value on the ripple voltage. Capacitors used were
multilayer ceramic with low ESR < 0.1 Ohms .

Typical Output rippl e vs Vi n (Io u t = 10mA)

150.0E-3

130.0E-3

110.0E-3

90.0E-3

Vout (V)

70.0E-3

50.0E-3

30.0E-3

2.50 3.00 3.50 4.00 4.50 5.00 5.50

Vin (V)

Cout = 3.3uF
Cout = 6.8uF
Cout = 10uF
Cout = 22uF

Following table shows typical capacitor characteristics :

Component ESR

(Ohms)

ESL
(nH)

Capacitor Manufacturers

Manufacturer 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

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 SC1517-5.

0.1 uF Ceramic 0603 package 0.100 1.60

1.0 uF Ceramic 1206 package 0.120 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

9

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

October 3, 2000

DEVICE OUTLINE SOT23-5L

MICROPOWER, REGULATED 5V
CHARGE PUMP

SC1517-5

LAND PATTERN SOT23-5L

ECN00-1360

10

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