MICROCHIP MCP1252, MCP1253 Technical data

M

Low Noise, Positive-Regulated Charge Pump

MCP1252/3

Features

• Inductorless, Buck/Boost, DC/DC Converter

• Low Power: 80 µA (Typical)

• High Output Voltage Accuracy:

- ±2.5% (V

• 120 mA Output Current

• Wide Operating Temperature Range:

- -40°C to +85°C

• Thermal Shutdown and Short-Circuit Protection

• Uses Small Ceramic Capacitors

• Switching Frequency:

- MCP1252: 650 kHz

- MCP1253: 1 MHz

• Low Power Shutdown Mode: 0.1 µA (Typical)

• Shutdown Input Compatible with 1.8V Logic

Range: 2.0V to 5.5V

•V

IN

• Selectable Output Voltage (3.3V or 5.0V) or
Adjustable Output Voltage

• Space-saving, 8-Lead MSOP

• Soft-Start Circuitry to Minimize In-Rush Current

OUT

Fixed)

Applications

• White LED Backlighting

• Color Display Bias

• Local 3V-to-5V Conversions

• Flash Memory Supply Voltage

• SIM Interface Supply for GSM Phones

• Smart Card Readers

• PCMCIA Local 5V Supplies

Description

The MCP1252/3 are inductorless, positive-regulated
charge pump DC/DC converters. The devices generate
a regulated fixed (3.3V or 5.0V) or adjustable output
voltage. They are specifically designed for applications
requiring low noise and high efficiency and are able to
deliver up to 120 mA output current. The devices allow
the input voltage to be lower or higher than the output
voltage, by automatically switching between buck/
boost operation.

The MCP1252 has a switching frequency of 650 kHz,
avoiding interference with sensitive IF bands. The
MCP1253 has a switching frequency of 1 MHz and
allows the use of smaller capacitors than the
MCP1252, thus saving board space and cost.

Both devices feature a power-good output that can be
used to detect out-of-regulation conditions. Extremely
low supply current and low external parts count (three
capacitors) make these devices ideal for small, battery­powered applications. A shutdown mode is also pro­vided for further power reduction. The MCP1252 and
MCP1253 feature thermal and short-circuit protection
and are offered in space-saving, 8-lead, MSOP
packages.

Package Types

MSOP (FIXED)

PGOOD

V

OUT

V

GND

1

MCP1252

2

MCP1253

IN

3

4

8

7

6

5

SELECT

SHDN

C+

C-

MSOP (ADJUSTABLE)

PGOOD

V

OUT

V

IN

GND

 2002 Microchip Technology Inc. DS21752A-page 1

1

2

MCP1252

3

MCP1253

4

8

7

6

5

FB

SHDN

C+

C-

MCP1252/3

Functional Block Diagram

MCP1252-33X50
MCP1253-33X50

PGOOD

V

OUT

V

GND

­+

+

84 mV

-

1.21V

+

-

Switch

Control

+

200 mV

IN

140 kΩ

173 kΩ

+

100 kΩ

+

SELECT

SHDN

C+
C-

MCP1252-ADJ
MCP1253-ADJ

PGOOD

V

OUT

V

GND

­+

+

84 mV

-

+

-

Switch

Control

+

200 mV

IN

1.21V

+

+

FB

SHDN

C+
C-

DS21752A-page 2  2002 Microchip Technology Inc.

MCP1252/3

1.0 ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings †

Power Supply Voltage, VIN...............................................6.0V

Voltage on Any Pin w.r.t. GND ............... -0.3V to (V

Output Short Circuit Duration ................................continuous

Storage Temperature Range.........................-65°C to +150°C

Ambient Temperature with Power Applied....-55°C to +125°C

Junction Temperature ................................................. +150°C

ESD Ratings:

Human Body Model (1.5 kΩ in Series with 100 pF ...... ≥ 4kV

Machine Body Model (200 pF, No Series Resistance ≥ 400V

+ 0.3V)

IN

PIN FUNCTION TABLE

Name Function

PGOOD Open-Drain Power GOOD Output

V

OUT

V

IN

GND Ground Terminal

C- Flying Capacitor Negative Terminal

C+ Flying Capacitor Positive Terminal

SHDN

SELECT

FB

Regulated Output Voltage

Power Supply Input

Shutdown Mode, Active-Low Input

Output Voltage Select Pin.
(MCP1252-33X50, MCP1253-33X50)

Feedback Input Pin for Adjustable Output
(MCP1252-ADJ, MCP1253-ADJ)

†Notice: Stresses above those listed under “Maximum Rat­ings” may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied. Expo­sure to maximum rating conditions for extended periods may
affect device reliability.

ELECTRICAL CHARACTERISTICS

Electrical Specifications: Unless otherwise specified, all limits are specified for TA = -40°C to +85°C, SHDN = VIN,

C

= C

OUT

= 10 µF, C

IN

Parameters Sym Min Typ Max Units Conditions

Selectable Output - MCP1252-33X50, MCP1253-33X50: SELECT = V

Supply Voltage V

Output Voltage Accuracy V

Output Current I

SELECT Logic Input Voltage High V

Selectable Output - MCP1252-33X50, MCP1253-33X50: SELECT = GND, V

Supply Voltage V

Output Voltage Accuracy V

Output Current I

SELECT Logic Input Voltage Low V

Adjustable Output - MCP1252-ADJ, MCP1253-ADJ

Supply Voltage V

Output Voltage Adjustment Range V

FB Regulation Voltage V

ALL DEVICES

Supply Current I

Output Short-Circuit Current I

Shutdown Current I

Power Efficiency η —8168—%%V

Logic Input Voltage Low V

SHDN

Logic Input Voltage High V

SHDN

PGOOD Threshold Voltage V

PGOOD Hysteresis V

FLY

= 1 µF, I

= 10 mA. Typical values are for TA = +25°C.

OUT

IN

OUT

OUT

IH

IN

OUT

OUT

IL

IN

OUT

FB

DD

SC

SHDN

IL

IH

TH

HYS

2.1 — 5.5 V

-2.5 +/-0.5 +2.5 % 2.3V ≤ VIN < 2.5V, I

80

120

100
150

1.4 — — V MCP1252-33X50, MCP1253-33X50

2.7 — 5.5 V

-2.5 +/-0.5 +2.5 % 2.7V ≤ V

40

120

80

150

— — 0.4 V MCP1252-33X50, MCP1253-33X50

2.0 — 5.5 V

1.5 — 5.5 V V

1.18 1.21 1.24 V MCP1252-ADJ, MCP1253-ADJ

—60120µANo load

—200 —mAV

— 0.1 2.0 µA SHDN = 0V

—— 0.4V

1.4 — — V

—0.93V

—0.04V

OUT

OUT

, V

OUT

= 3.3V

IN

2.5V ≤ V

—mAmA2.3V ≤ VIN < 2.5V

2.5V ≤ V

= 5.0V

OUT

3.0V ≤ V

—mAmA2.7V ≤ VIN < 3.0V

3.0V ≤ V

OUT(MAX)

OUT

= 3.0V, V

IN

V

= 3.6V, V

IN

I

OUT

—V

—V

≤ 5.5V, I

IN

≤ 5.5V

IN

< 3.0V, I

IN

≤ 5.5V, I

IN

≤ 5.5V

IN

< 2 x V

= GND, foldback current

OUT

OUT

=120 mA

OUT

OUT

OUT

OUT

IN

= 5V
= 5V

≤ 80 mA

≤ 120 mA

≤ 40 mA

≤ 120 mA

 2002 Microchip Technology Inc. DS21752A-page 3

MCP1252/3

AC CHARACTERISTICS

Electrical Specifications: Unless otherwise specified, all limits are specified for T

V

= 2.7V to 5.5V, SELECT = GND, SHDN = VIN, C

IN

Typical values are for T

= +25°C.

A

IN

= C

OUT

= 10 µF, C

FLY

= 1 µF, I

Parameters Sym Min Typ Max Units Conditions

Internal Oscillator Frequency F

Ripple Voltage V

V

Wake-Up Time From Shutdown T

OUT

OSC

RIP

WKUP

520
800

—5045—mV

—200

650

1000

780

1200

—µsec

300

TEMPERATURE SPECIFICATIONS

Parameters Symbol Min Typ Max Units Conditions

Temperature Ranges:

Specified Temperature Range T

Maximum Operating Junction
Temperature

Storage Temperature Range T

Thermal Package Resistances:

Thermal Resistance, 8 Pin MSOP θ

A

T

J

A

JA

-40 — +85 °C

— — +125 °C

-65 — +150 °C

— 206 — °C/W Single-Layer SEMI G42-88

= -40°C to +85°C,

A

= 10 mA.

OUT

kHz

MCP1252

kHz

MCP1253

MCP1252

p-p

p-p

MCP1253

mV

SELECT = V

µsec

SELECT = GND
V

= 3.6V, I

IN

SHDN

= V

V

from 0 to 90% Nominal

OUT

Regulated Output Voltage

Board, Natural Convection

IN

OUT

IH(MIN)

= 10 mA,

,

DS21752A-page 4  2002 Microchip Technology Inc.

MCP1252/3

2.0 TYPICAL PERFORMANCE CURVES

Note: The graphs and tables provided following this note are a statistical summary based on a limited number of

samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.

Note: Unless otherwise indicated, V

= 3.6V, TA = 25°C, CIN = C

IN

= 10µF, C

OUT

= 1µF, all capacitors X7R ceramic.

FLY

5.05

5.04

10 mA

5.03

5.02
80 mA 120 mA

5.01

Output Voltage (V)

5.00

4.99

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Supply Voltage (V)

MCP125 2-33X50
SELECT = GND

OUT

= 5.0V

V

FIGURE 2-1: Output Voltage vs. Supply Voltage (MCP1252-33X50).

.

3.34

3.33

3.32

Output Voltage (V)

MCP125 2-33X50
SELECT = V
V

3.31

OUT

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

IN

= 3.3V

Supply Voltage (V)

80 mA

120 mA

10 mA

100

90
80
70
60
50
40
30
20

Percent Efficiency (%)

10

0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Supply Voltage (V)

10 mA

80 mA

120 mA

MCP125 2-33X50
SELECT = GND

= 5.0V

V

OUT

FIGURE 2-4: Percent Efficiency vs. Supply Voltage (MCP1252-33X50).

100

90
80
70
60
50
40
30
20

Power Efficiency (%)

10

0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

10 mA

80 mA

120 mA

Supply Voltage (V)

MCP125 2-33X50
SELECT = V
V

= 3.3V

OUT

IN

FIGURE 2-2: Output Voltage vs. Supply Voltage (MCP1252-33X50).

3.02

3.01

10 mA

3.00

Output Voltage (V)

2.99

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

80 mA

120 mA

Supply Voltage (V)

MCP125 2-ADJ

= 3.0V

V

OUT

FIGURE 2-3: Output Voltage vs. Supply Voltage (MCP1252-ADJ).

FIGURE 2-5: Power Efficiency vs. Supply Voltage (MCP1252-33X50).

100

90
80
70
60
50
40
30
20

Power Efficiency (%)

10

0

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

10 mA

80 mA

120 mA

Supply Voltage (V)

MCP125 2-ADJ

= 3.0V

V

OUT

FIGURE 2-6: Power Efficiency vs. Supply
Voltage

(MCP1252-ADJ).

 2002 Microchip Technology Inc. DS21752A-page 5

MCP1252/3

Note: Unless otherwise indicated, V

5.03

5.02

5.01

5.00

Output Voltage (V)

4.99

4.98

MCP125 3-33X50

MCP125 2-33X50

-40 -25 -10 5 20 35 50 65 80 95 110 125

Temperature (°C)

= 3.6V, TA = 25°C, CIN = C

IN

SELECT = GND

= 5.0V

V

OUT

I

= 120 mA

OUT

FIGURE 2-7: Output Voltage vs. Temperature (MCP1252-33X50, MCP1253-33X50).

3.33

3.32

3.31

3.30

3.29

Output Voltage (V)

3.28

MCP125 3-33X50

MCP125 2-33X50

SELECT = V
V

= 3.3V

OUT

I

= 120 mA

OUT

-40 -25 -10 5 20 35 50 65 80 95 110 125

Temperature (°C)

= 10 mF, C

OUT

80

75

70

65

60

55

50

Supply Current (uA)

45

40

-40 -25 -10 5 20 35 50 65 80 95 110 125

= 1 mF, all capacitors X7R ceramic.

FLY

VIN = 5.5V

VIN = 3.6V

VIN = 2.7V

VIN = 2.3V

Temperature (°C)

MCP1253-33X50
SELECT = GND
V

= 5.0V, I

OUT

OUT

= 0 mA

FIGURE 2-10: Quiescent Current vs. Temperature (MCP1253-33X50).

80

VIN = 5.5V

75

70

65

60

IN

55

50

Supply Current (uA)

45

40

VIN = 3.6V

VIN = 2.7V

VIN = 2.3V

-40 -25 -10 5 20 35 50 65 80 95 110 125

Temperature (°C)

MCP1252-33X50
SELECT = GND
V

= 5.0V, I

OUT

OUT

= 0 mA

FIGURE 2-8: Output Voltage vs. Temperature (MCP1252-33X50, MCP1253-33X50).

FIGURE 2-9: Line Transient Response.

FIGURE 2-11: Quiescent Current vs.

Temperature (MCP1252-33X50).

FIGURE 2-12: Load Transient Response.

DS21752A-page 6  2002 Microchip Technology Inc.

MCP1252/3

Note: Unless otherwise indicated, V

70

60

50

80 mA

40

10 mA
120 mA

30

20

10

Output Voltage Ripple (mV)

0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Supply Voltage (V)

= 3.6V, TA = 25°C, CIN = C

IN

MCP125 2-33X50
SELECT = GND

= 5.0V

V

OUT

FIGURE 2-13: Output Voltage Ripple vs. Supply Voltage (MCP1252-33X50).

70

60

50

120 mA

40

80 mA

30

10 mA

20

10

Output Voltage Ripple (mV)

0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Supply Voltage (V)

MCP125 2-33X50
SELECT = V
V

OUT

= 3.3V

IN

= 10mF, C

OUT

= 1mF, all capacitors X7R ceramic.

FLY

FIGURE 2-16: Output Voltage Ripple vs. Time.

FIGURE 2-14: Output Voltage Ripple vs. Supply Voltage (MCP1252-33X50).

FIGURE 2-15: Start-Up (MCP1252-33X50).

FIGURE 2-17: Output Voltage Ripple vs.

Time.

FIGURE 2-18: Start-Up (MCP1253-33X50).

 2002 Microchip Technology Inc. DS21752A-page 7

MCP1252/3

3.0 PIN FUNCTIONS

TABLE 3-1: PIN FUNCTION TABLE

Pin
No.

3.1 Open-Drain Power Good Output

PGOOD is a high-impedance when the output voltage
is in regulation. A logic-low is asserted when the output
falls 7% (typical) below the nominal value. The PGOOD
output remains low until V
its nominal value. On start-up, this pin indicates when
the output voltage reaches its final value. PGOOD is
high-impedance when SHDN

Name Function

1 PGOOD

2V

3V

4GND

5C-

6C+

7 SHDN

8 SELECT

Open-Drain Power GOOD Output

Regulated Output Voltage

OUT

Power Supply Input

IN

Ground Terminal

Flying Capacitor Negative Terminal

Flying Capacitor Positive Terminal

Shutdown Mode, Active-Low Input

Output Voltage Select Pin.
(MCP1252-33X50, MCP1253-33X50)

Feedback Input Pin for Adjustable Output

FB

(MCP1252-ADJ, MCP1253-ADJ)

(PGOOD)

OUT

is within 3% (typical) of

is low.

3.6 Flying Capacitor Positive Terminal (C+)

The charge pump capacitor (flying capacitor) is used to
transfer charge from the input supply to the regulated
output.

Proper orientation is imperative when using a polarized
capacitor.

3.7 Shutdown Input (SHDN)

A logic-low signal applied to SHDN disables the device.
A logic-high signal applied to this pin allows normal
operation.

3.8 Select (SELECT) Input or Feedback (FB) Input

MCP1252-33X50, MCP1253-33X50:
SELECT: Select Input Pin.

Connect SELECT to V
SELECT to GND for a 5.0V fixed output.

MCP1252-ADJ, MCP1253-ADJ:
FB: Feedback Pin.

A resistor divider connected to this pin determines the
adjustable V

value (1.5V to 5.5V).

OUT

for 3.3V fixed output. Connect

IN

3.2 Regulated Output Voltage (V

Bypass to GND with a filter capacitor.

OUT

)

3.3 Power Supply Input (VIN)

It is recommended that VIN be tied to a ceramic bypass
capacitor.

3.4 Ground (GND)

It is recommended that the ground pin be tied to a
ground plane for best performance.

3.5 Flying Capacitor Negative Ter m inal (C-)

The charge pump capacitor (flying capacitor) is used to
transfer charge from the input supply to the regulated
output.

It is recommended that a low ESR (equivalent series
resistance) capacitor be used.

DS21752A-page 8  2002 Microchip Technology Inc.

4.0 DEVICE OVERVIEW

MCP1252/3

4.1 Theory of Operation

The MCP1252 and MCP1253 family of devices employ
a switched capacitor charge pump to buck or boost an
input supply voltage (V
Referring to the Functional Block Diagram and
Figure 4-1, the devices perform conversion and regula­tion in three phases. When the devices are not in shut­down mode and a steady-state condition has been
reached, the three phases are continuously cycled
through. The first phase transfers charge from the input
to the flying capacitor (C
C-. This phase always occurs for half of the internal
oscillator period. During this phase, switches S
are closed.

Once the first phase is complete, all switches are
opened and the second phase (idle phase) is entered.
The device compares the internal or external feedback
voltage with an internal reference. If the feedback volt­age is below the regulation point, the device transitions
to the third phase.

The third phase transfers energy from the flying capac­itor to the output capacitor connected to V
load. If regulation is maintained, the device returns to
the idle phase. If the charge transfer occurs for half the
internal oscillator period, more charge is needed in the
flying capacitor and the device transitions back to the
first phase.

The regulation control is hysteretic, otherwise referred
to as a bang-bang control. The output is regulated
around a fixed reference with some hysteresis. As a
result, typically 50 mV of peak-to-peak ripple will be
observed at the output independent of load current.
The frequency of the output ripple, however, will be
influenced heavily by the load current and output
capacitance. The maximum frequency that will be
observed is equal to the internal oscillator frequency.

The devices automatically transition between buck or
boost operation. This provides a low-cost, compact and
simple solution for step-down/step-up DC/DC conver­sion. This is especially true for battery-operated appli­cations that require a fixed output above or below the
input.

) to a regulated output voltage.

IN

) connected to pins C+ and

FLY

and S

1

and the

OUT

START

PHASE 1:

Charge Transfer
From V

No

2

PHASE 2:

Idle State

PHASE 3:

Charge Transfer
From C

No

Ye s

t1 = 2F

V

FB

t

= 2F

3

V

FB

IN

> V

FLY

> V

to C

1

OSC

Ye s

REF

No

to C

1

OSC

No

REF

FLY

Yes

OUT

Yes

FIGURE 4-1: Flow Algorithm.

 2002 Microchip Technology Inc. DS21752A-page 9

MCP1252/3

4.2 Power Efficiency

The power efficiency, η, is determined by the mode of
operation. In boost mode, the efficiency is approxi­mately half of a linear regulator. In buck mode, the effi­ciency is approximately equal to that of a linear
regulator. The following formulas can be used to
approximate the power efficiency with any significant
amount of output current. At light loads, the quiescent
current of the device must be taken into consideration.

EQUATION

η

BOOST

P

OUT

-------------

== =

P

IN

P

OUT

η

BUCK

-------------

== =

P

IN

×

V

OUTIOUT

------------- ------------ -----------

V

×

2× I

IN

OUT

×

V

OUTIOUT

------------ ------------- -------

V

×

INIOUT

V

OUT

---------- --------

VIN2×

V

OUT

-------------

V

IN

4.3 Shutdown Mode

Driving SHDN low places the MCP1252 or MCP1253 in
a low power shutdown mode. This disables the charge
pump switches, oscillator and control logic, reducing
the quiescent current to 0.1 µA (typical). The PGOOD
output is in a high-impedance state during shutdown.

4.4 PGOOD Output

The PGOOD output is an open-drain output that sinks
current when the regulator output voltage falls below

0.93V

(typical). The output voltage can either be

OUT

fixed when the selectable output device is chosen
(MCP1252-33X50, MCP1253-33X50) or adjustable
from an external resistive divider when the adjustable
device is chosen (MCP1252-ADJ, MCP1253-ADJ). If
the regulator output voltage falls below 0.93V

OUT

(typ­ical) for less than 200 µsec and then recovers, glitch­immunity circuits prevent the PGOOD signal from tran­sitioning low. A 10 kΩ to 1 MΩ pull-up resistor from
PGOOD to V

may be used to provide a logic output.

OUT

Connect PGOOD to GND or leave unconnected if not
used.

4.5 Soft-Start and Short-Circuit

Protection

The MCP1252 and MCP1253 features foldback short­circuit protection. This circuitry provides an internal
soft-start function by limiting in-rush current during
startup and also limits the output current to 200 mA
(typical) if the output is shorted to GND. The internal
soft-start circuitry requires approximately 300 µsec,
typical with a 5V output, from either initial power-up or
release from shutdown for the output voltage to be in
regulation.

4.6 Thermal Shutdown

The MCP1252 and MCP1253 feature thermal shut­down with temperature hysteresis. When the die tem­perature exceeds 160°C, typically, the device shuts
down. When the die cools by 15°C, typically, the device
automatically turns back on. If high die temperature is
caused by output overload and the load is not removed,
the device will turn on and off, resulting in a pulse out­put.

5.0 APPLICATIONS

The MCP1252 and MCP1253 are inductorless, positive
regulated, charge pump DC/DC converters. A typical
circuit configuration for the fixed output version is
depicted in Figure 5-1. The adjustable version is
depicted in Figure 5-2.

SELECTABLE OUTPUT VOLTAGE

MCP1252-33X50

6

C

FLY

2.7V to 5.5V

+

C

IN

ON

OFF

Shutdown

Control

5

3

7

C+

C-

V

IN

SHDN

V

PGOOD

SELECT

GND

4

FIGURE 5-1: Typical Circuit Configuration for Fixed Output Device.

ADJUSTABLE OUTPUT VOLTAGE

MCP1252-ADJ

6

C

FLY

2.7V to 5.5V

+

+

C

IN

ON

OFF

Shutdown

Control

C+

5

C-

3

V

IN

7

SHDN

= 1.21V (1 + R1/R2)

V

OUT

V

PGOOD

GND

4

FIGURE 5-2: Typical Circuit Configuration for Adjustable Output Device.

OUT

OUT

FB

+5.0V ±2.5%

2

R

PU

1

PGOOD Flag

8

To P I C m i c ro
Microcontroller

C

FLY =

C

IN =

C

OUT =

R

PU =

+4.0V

2

R

PU

R

1

1

PGOOD Flag

8

To P I C m i c ro
Microcontroller

R

2

C

FLY =

C

IN =

C

OUT =

R

PU =

R

1 =

R

2 =

+

C

OUT

®

1µF

10 µF

10 µF

100 kΩ

+

C

OUT

1µF

10 µF

10 µF

100 kΩ

23.2 kΩ
10 kΩ

®

DS21752A-page 10  2002 Microchip Technology Inc.

MCP1252/3

5.1 Capacitor Selection

The style and value of capacitors used with the
MCP1252 and MCP1253 family of devices determine
several important parameters such as output voltage
ripple and charge pump strength. To minimize noise
and ripple, it is recommended that low ESR (0.1 Ω)
capacitors be used for both C

and C

IN

OUT

. These
capacitors should be either ceramic or tantalum and
should be 10 µF or higher. Aluminum capacitors are not
recommended because of their high ESR.

If the source impedance to V
megahertz, C

may not be required. Alternatively, a

IN

somewhat smaller value of C

is very low, up to several

IN

may be substituted for

IN

the recommended 10 µF, but will not be as effective in
preventing ripple on the V

The value of C

controls the amount of output volt-

OUT

age ripple present on V
C

will reduce output ripple at the expense of a

OUT

pin.

IN

. Increasing the size of

OUT

slower turn-on time from shutdown and a higher in-rush
current.

The flying capacitor (C

) controls the strength of the

FLY

charge pump. In order to achieve the maximum rated
output current (120 mA), it is necessary to have at least
1 µF of capacitance for the flying capacitor. A smaller
flying capacitor delivers less charge per clock cycle to
the output capacitor, resulting in lower output ripple.
The output ripple is reduced at the expense of maxi­mum output current and efficiency.

5.2 Output Voltage Setting

Note that the tolerance of the external resistors will
have an effect on the accuracy of the output voltage.
For optimum results, it is recommended that the
external resistors have a tolerance no larger than 1%.

5.3 Recommended Layout

The MCP1252 and MCP1253 family of devices transfer
charge at high switching frequencies, producing fast,
high peak, transient currents. As a result, any stray
inductance in the component layout will produce
unwanted noise in the system. Proper board layout
techniques are required to ensure optimum perfor­mance. Figure 5-3 depicts the recommended board
layout. The input capacitor connected between V
GND, and the output capacitor connected between
V

and GND, are 10 µF ceramic, X7R dielectric, in

OUT

1206 packages. The flying capacitor connected
between C+ and C- is a 1 µF ceramic, X7R dielectric in
a 0805 package. The layout is scaled 3:1.

PGOOD

V

OUT

GND

V

IN

and

IN

SELECT
SHDN

C+

C-

The MCP1252-33X50 and MCP1253-33X50 feedback
controllers select between an internally-set, regulated
output voltage (3.3V or 5.0V). Connect SELECT to
GND for a regulated 5.0V output and connect SELECT
to V

for a regulated 3.3V output.

IN

The MCP1252-ADJ and MCP1253-ADJ utilize an
external resistor divider that allows the output voltage
to be adjusted between 1.5V and 5.5V. For an adjust­able output, connect a resistor between V
(R

) and another resistor between FB and GND (R2). In

1

the following equation, choose R
equal to 30 kΩ and calculate R

to be less than or

2

from the following

1

OUT

and FB

formula:

EQUATION

R1R2V

and

⁄()1–[]=

OUTVFB

EQUATION

V

OUTVFB

where:

V

is the desired output voltage from 1.5V to 5.5V

OUT

is the internal regulation voltage, nominally 1.21V

V

FB

1R1R

⁄+()=

2

FIGURE 5-3: Recommended Printed Circuit Board Layout.

 2002 Microchip Technology Inc. DS21752A-page 11

MCP1252/3

6.0 TYPICAL APPLICATION CIRCUITS

Single Cell Lithium-Ion Battery To 5V Converter

1µF

56

C+C-

Single
Li-Ion
Cell

10 µF

+

-

White LED Bias

100 kΩ

V

IN

78

SHDN

1

PGOOD

MCP1252-33X50

V

OUT

SELECT

GND

23

10 µF

4

5V

Single
Li-Ion
Cell

PWM Contrast
Control

10 µF

+

-

100 kΩ

Alternative White LED Bias

Single
Li-Ion
Cell

10 µF

+

-

100 kΩ

1µF

56

C+C-

V

IN

78

SHDN

1

PGOOD

V

78

SHDN

1

PGOOD

SELECT

MCP1252-ADJ

1µF

56

IN

SELECT

V

GND

C+C-

V

GND

OUT

OUT

23

4

23

4

UP TO 6 WHITE LEDS

10 µF

UP TO 6 WHITE LEDS

24 kΩ

10 µF

10 kΩ

59 Ω59 Ω59 Ω59 Ω 59 Ω59 Ω

10 Ω 10 Ω 10 Ω 10 Ω 10 Ω 10 Ω

PWM Contrast
Control

DS21752A-page 12  2002 Microchip Technology Inc.

MCP1252-ADJ

7.0 PACKAGING INFORMATION

7.1 Package Marking

MCP1252/3

8-Lead MSOP (Fixed)

XXXXX

YWWNNN

8-Lead MSOP (Adjustable)

XXXXX

YWWNNN

Example:

1252SX

233025

Example:

1253DJ

233025

Legend: XX...X Customer specific information*

YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code

Note: In the event the full Microchip part number cannot be marked on one line, it will

be carried over to the next line thus limiting the number of available characters
for customer specific information.

* Standard OTP marking consists of Microchip part number, year code, week code, and traceability code.

 2002 Microchip Technology Inc. DS21752A-page 13

MCP1252/3

8-Lead Plastic Micro Small Outline Package (MS) (MSOP)

E

E1

p

D

2

B

n 1

α

A

c

(F)

β

Units

Dimension Limits

Number of Pins

Pitch

Overall Height

Molded Package Thickness

Standoff §

Overall Width

Molded Package Width

Overall Length

Foot Length

Foot Angle

Lead Thickness

Lead Width

Mold Draft Angle Top

Mold Draft Angle B ottom

*Controlling Parameter

§ Significant Characteristic

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254 mm) per side.

n
p

A

A2

A1

E

E1

D

L

φ

c

B

α

β

MIN

.030

.002

.184

.114

.114

.016

0

.004

.010

L

INCHES

NOM

.026

.034

.193

.118

.118

.022

.037.035FFootprint (Referen ce)

.006

.012

φ

A1

8

.044

.038

.006

.200

.122

.122

.028

6

.008

.016

7

7

MILLIMETERS*

MINMAX NOM

0.65

0.76

0.05

4.67

2.90

2.90

0.40

0

0.10

0.25

0.86

4.90

3.00

3.00

0.55

0.15

0.30

A2

MAX

8

1.18

0.97

0.15

.5.08

3.10

3.10

0.70

1.000.950.90.039

6

0.20

0.40

7

7

Drawing No. C04-111

DS21752A-page 14  2002 Microchip Technology Inc.

MCP1252/3

PRODUCT IDENTIFICATION SYSTEM

To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.

PART NO. X /XX

Device

Device: MCP1252: Low Noise, Positive-Regulated Charge Pump

Tem perature Range: I = -40°C to +85°C

Package: MS = Plastic Micro Small Outline (MSOP), 8-lead

Range

MCP1252T: Low Noise, Positive-Regulated Charge Pump

MCP1253: Low Noise, Positive-Regulated Charge Pump
MCP1253T: Low Noise, Positive-Regulated Charge Pump

PackageTemp era tur e

(Tape and Reel)

(Tape and Reel)

Sales and Support

Data Sheets

Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom­mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:

Examples:

a) MCP1252-33X50I/MS: Low Noise, Positive-

Regulated Charge Pump, Fixed Output

b) MCP1252-ADJI/MS: Low Noise, Positive-

Regulated Charge Pump, Adjustable
Output

c) MCP1252T-33X50I/MS: Tape and Reel,

Low Noise, Positive-Regulated Charge
Pump, Fixed Output

a) MCP1253-33X50I/MS: Low Noise, Posi-

tive-Regulated Charge Pump, Fixed Output

b) MCP1253-ADJI/MS: Low Noise, Posi-

tive-Reg ulated Charge Pump, Adjustable
Output

c) MCP1253T-ADJI/MS: Tape and Reel,

Low Noise, Positive-Regulated Charge
Pump, Adjustable Output

1. Your local Microchip sales office

2. The Microchip Corporate Literature Center U.S. FAX: [phone]

3. The Microchip Worldwide Site (www.microchip.com)

Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.

New Customer Notification System

Register on our web site (www.microchip.com/cn) to receive the most current information on our products.

 2002 Microchip Technology Inc. DS21752A-page15

MCP1252/3

NOTES:

DS21752A-page 16  2002 Microchip Technology Inc.

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowl­edge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products.

Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com­ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con­veyed, implicitly or otherwise, under any intellectual property
rights.

Trademarks

The Microchip name and logo, the Microchip logo, K

EELOQ

MPLAB, PIC, PICmicro, PICSTART and PRO MATE are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.

FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.

dsPIC, dsPICDEM.net, ECONOMONITOR, FanSense,
FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP,
ICEPIC, microPort, Migratable Memory, MPASM, MPLIB,
MPLINK, MPSIM, PICC, PICDEM, PICDEM.net, rfPIC, Select
Mode and Total Endurance are trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.

Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.

All other trademarks mentioned herein are property of their
respective companies.

© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.

Printed on recycled paper.

,

Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog produ cts. In
addition, Microchip’s qua lity system for the
design and manufacture of development
systems is ISO 9001 certified.

®

8-bit MCUs, KEEL

®

code hopping

OQ

 2002 Microchip Technology Inc. DS21752A - page 17

M

W

ORLDWIDE SALES AND SERVICE

AMERICAS

Corporate Office

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11/ 15/ 02

DS21752A-page 18  2002 Microchip Technology Inc.