MCP1252T-33X50I/MS [MICROCHIP]
Low Noise, Positive-Regulated Charge Pump; 低噪声正向调节电荷泵型号: | MCP1252T-33X50I/MS |
厂家: | MICROCHIP |
描述: | Low Noise, Positive-Regulated Charge Pump |
文件: | 总18页 (文件大小:428K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
MCP1252/3
M
Low Noise, Positive-Regulated Charge Pump
Features
Description
• Inductorless, Buck/Boost, DC/DC Converter
• Low Power: 80 µA (Typical)
• High Output Voltage Accuracy:
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, battery-
powered applications. A shutdown mode is also pro-
vided for further power reduction. The MCP1252 and
MCP1253 feature thermal and short-circuit protection
and are offered in space-saving, 8-lead, MSOP
packages.
- ±2.5% (V
Fixed)
OUT
• 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
• V Range: 2.0V to 5.5V
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
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
Package Types
MSOP (FIXED)
PGOOD
VOUT
VIN
SELECT
SHDN
C+
1
2
3
4
8
7
6
5
MCP1252
MCP1253
• PCMCIA Local 5V Supplies
GND
C-
MSOP (ADJUSTABLE)
PGOOD
VOUT
VIN
1
2
3
4
8
FB
7
6
5
SHDN
C+
MCP1252
MCP1253
GND
C-
2002 Microchip Technology Inc.
DS21752A-page 1
MCP1252/3
Functional Block Diagram
MCP1252-33X50
MCP1253-33X50
PGOOD
SELECT
140 kΩ
-
+
173 kΩ
100 kΩ
+
-
84 mV
1.21V
+
+
+
-
+
200 mV
VOUT
SHDN
C+
C-
Switch
Control
VIN
GND
MCP1252-ADJ
MCP1253-ADJ
PGOOD
FB
-
+
+
-
84 mV
+
+
1.21V
+
-
+
200 mV
VOUT
SHDN
C+
C-
Switch
Control
VIN
GND
DS21752A-page 2
2002 Microchip Technology Inc.
MCP1252/3
1.0
ELECTRICAL
PIN FUNCTION TABLE
CHARACTERISTICS
Name
Function
Absolute Maximum Ratings †
PGOOD
VOUT
VIN
GND
C-
Open-Drain Power GOOD Output
Regulated Output Voltage
Power Supply Input
Power Supply Voltage, VIN...............................................6.0V
Voltage on Any Pin w.r.t. GND ............... -0.3V to (VIN + 0.3V)
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:
Ground Terminal
Flying Capacitor Negative Terminal
Flying Capacitor Positive Terminal
Shutdown Mode, Active-Low Input
Output Voltage Select Pin.
(MCP1252-33X50, MCP1253-33X50)
C+
SHDN
SELECT
FB
Human Body Model (1.5 kΩ in Series with 100 pF ......≥ 4 kV
Machine Body Model (200 pF, No Series Resistance ≥ 400V
Feedback Input Pin for Adjustable Output
(MCP1252-ADJ, MCP1253-ADJ)
†Notice: Stresses above those listed under “Maximum Rat-
ings” 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. Expo-
sure 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
IN = COUT = 10 µF, CFLY = 1 µF, IOUT = 10 mA. Typical values are for TA = +25°C.
Parameters Sym Min Typ Max
Selectable Output - MCP1252-33X50, MCP1253-33X50: SELECT = VIN, VOUT = 3.3V
Units
Conditions
Supply Voltage
VIN
2.1
—
5.5
V
Output Voltage Accuracy
VOUT
-2.5
+/-0.5
+2.5
%
2.3V ≤ VIN < 2.5V, IOUT ≤ 80 mA
2.5V ≤ VIN ≤ 5.5V, IOUT ≤ 120 mA
Output Current
IOUT
80
100
150
—
—
—
mA
mA
V
2.3V ≤ VIN < 2.5V
2.5V ≤ VIN ≤ 5.5V
MCP1252-33X50, MCP1253-33X50
120
SELECT Logic Input Voltage High
VIH
1.4
Selectable Output - MCP1252-33X50, MCP1253-33X50: SELECT = GND, VOUT = 5.0V
Supply Voltage
VIN
2.7
—
5.5
V
Output Voltage Accuracy
VOUT
-2.5
+/-0.5
+2.5
%
2.7V ≤ VIN < 3.0V, IOUT ≤ 40 mA
3.0V ≤ VIN ≤ 5.5V, IOUT ≤ 120 mA
Output Current
IOUT
40
120
80
150
—
mA
mA
2.7V ≤ VIN < 3.0V
3.0V ≤ VIN ≤ 5.5V
SELECT Logic Input Voltage Low
VIL
—
—
0.4
V
MCP1252-33X50, MCP1253-33X50
Adjustable Output - MCP1252-ADJ, MCP1253-ADJ
Supply Voltage
VIN
VOUT
VFB
2.0
1.5
1.18
—
—
1.21
5.5
5.5
1.24
V
V
V
Output Voltage Adjustment Range
FB Regulation Voltage
ALL DEVICES
VOUT(MAX) < 2 x VIN
MCP1252-ADJ, MCP1253-ADJ
Supply Current
Output Short-Circuit Current
Shutdown Current
IDD
ISC
ISHDN
η
—
—
—
—
60
200
0.1
81
68
120
—
2.0
—
µA
mA
µA
%
%
No load
VOUT = GND, foldback current
SHDN = 0V
Power Efficiency
VIN = 3.0V, VOUT = 5V
V
IN = 3.6V, VOUT = 5V
I
OUT =120 mA
SHDN Logic Input Voltage Low
SHDN Logic Input Voltage High
PGOOD Threshold Voltage
PGOOD Hysteresis
VIL
VIH
VTH
VHYS
—
1.4
—
—
—
0.4
—
—
—
V
V
V
V
0.93VOUT
0.04VOUT
—
2002 Microchip Technology Inc.
DS21752A-page 3
MCP1252/3
AC CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all limits are specified for T = -40°C to +85°C,
A
V
= 2.7V to 5.5V, SELECT = GND, SHDN = V , C = C
= 10 µF, C
= 1 µF, I
= 10 mA.
IN
IN
IN
OUT
FLY
OUT
Typical values are for T = +25°C.
A
Parameters
Sym
Min
Typ
Max
Units
Conditions
Internal Oscillator Frequency
F
520
800
650
1000
780
1200
kHz MCP1252
kHz MCP1253
OSC
Ripple Voltage
V
—
50
—
—
mV
MCP1252
RIP
p-p
p-p
45
mV
MCP1253
V
Wake-Up Time From Shutdown T
—
200
300
µsec SELECT = V
µsec SELECT = GND
OUT
WKUP
IN
V
= 3.6V, I
= 10 mA,
,
IN
OUT
IH(MIN)
SHDN = V
V
from 0 to 90% Nominal
OUT
Regulated Output Voltage
TEMPERATURE SPECIFICATIONS
Parameters
Symbol
Min
Typ
Max
Units
Conditions
Temperature Ranges:
Specified Temperature Range
Maximum Operating Junction
Temperature
T
T
-40
—
—
—
+85
+125
°C
°C
A
J
Storage Temperature Range
Thermal Package Resistances:
Thermal Resistance, 8 Pin MSOP
T
-65
—
—
+150
—
°C
A
θ
206
°C/W Single-Layer SEMI G42-88
Board, Natural Convection
JA
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, T = 25°C, C = C
= 10 µF, C = 1 µF, all capacitors X7R ceramic.
FLY
IN
A
IN
OUT
100
90
80
70
60
50
40
30
20
10
0
5.05
5.04
5.03
5.02
5.01
5.00
4.99
10 mA
80 mA
10 mA
80 mA
120 mA
120 mA
MCP1252-33X50
SELECT = GND
VOUT = 5.0V
MCP1252-33X50
SELECT = GND
VOUT = 5.0V
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
FIGURE 2-1:
Output Voltage vs. Supply
FIGURE 2-4:
Percent Efficiency vs.
Voltage (MCP1252-33X50).
Supply Voltage (MCP1252-33X50).
.
3.34
3.33
100
90
80
10 mA
70
60
50
40
30
20
10
0
80 mA
120 mA
80 mA
120 mA
10 mA
3.32
MCP1252-33X50
SELECT = VIN
VOUT = 3.3V
MCP1252-33X50
SELECT = VIN
VOUT = 3.3V
3.31
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
FIGURE 2-2:
Output Voltage vs. Supply
FIGURE 2-5:
Power Efficiency vs. Supply
Voltage (MCP1252-33X50).
Voltage (MCP1252-33X50).
3.02
3.01
3.00
2.99
100
90
80
10 mA
70
80 mA
120 mA
60
50
40
30
20
10
0
10 mA
80 mA
MCP1252-ADJ
VOUT = 3.0V
MCP1252-ADJ
VOUT = 3.0V
120 mA
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Supply Voltage (V)
FIGURE 2-3:
Output Voltage vs. Supply
FIGURE 2-6:
Power Efficiency vs. Supply
Voltage (MCP1252-ADJ).
Voltage (MCP1252-ADJ).
2002 Microchip Technology Inc.
DS21752A-page 5
MCP1252/3
Note: Unless otherwise indicated, V = 3.6V, T = 25°C, C = C
= 10 mF, C = 1 mF, all capacitors X7R ceramic.
FLY
IN
A
IN
OUT
80
75
70
65
60
55
50
45
40
5.03
5.02
5.01
5.00
4.99
4.98
VIN = 5.5V
VIN = 3.6V
VIN = 2.7V
MCP1253-33X50
MCP1252-33X50
SELECT = GND
VOUT = 5.0V
VIN = 2.3V
MCP1253-33X50
SELECT = GND
I
OUT = 120 mA
VOUT = 5.0V, IOUT = 0 mA
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (°C)
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (°C)
FIGURE 2-7:
Output Voltage vs.
FIGURE 2-10:
Quiescent Current vs.
Temperature (MCP1252-33X50,
MCP1253-33X50).
Temperature (MCP1253-33X50).
3.33
80
75
70
VIN = 5.5V
MCP1253-33X50
3.32
VIN = 3.6V
65
60
3.31
MCP1252-33X50
VIN = 2.7V
3.30
3.29
3.28
SELECT = VIN
VOUT = 3.3V
55
50
45
40
MCP1252-33X50
SELECT = GND
VIN = 2.3V
I
OUT = 120 mA
V
OUT = 5.0V, IOUT = 0 mA
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (°C)
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (°C)
FIGURE 2-8:
Output Voltage vs.
FIGURE 2-11:
Quiescent Current vs.
Temperature (MCP1252-33X50,
MCP1253-33X50).
Temperature (MCP1252-33X50).
FIGURE 2-9:
Line Transient Response.
FIGURE 2-12:
Load Transient Response.
DS21752A-page 6
2002 Microchip Technology Inc.
MCP1252/3
Note: Unless otherwise indicated, V = 3.6V, T = 25°C, C = C
= 10mF, C = 1mF, all capacitors X7R ceramic.
FLY
IN
A
IN
OUT
70
60
50
40
30
20
10
0
80 mA
10 mA
120 mA
MCP1252-33X50
SELECT = GND
VOUT = 5.0V
2.0 2.5
3.0 3.5
4.0
4.5 5.0
5.5 6.0
Supply Voltage (V)
FIGURE 2-13:
Output Voltage Ripple vs.
FIGURE 2-16:
Output Voltage Ripple vs.
Supply Voltage (MCP1252-33X50).
Time.
70
60
50
120 mA
80 mA
40
30
10 mA
MCP1252-33X50
20
10
0
SELECT = VIN
VOUT = 3.3V
2.0 2.5
3.0 3.5
4.0
4.5 5.0
5.5 6.0
Supply Voltage (V)
FIGURE 2-14:
Output Voltage Ripple vs.
FIGURE 2-17:
Output Voltage Ripple vs.
Supply Voltage (MCP1252-33X50).
Time.
FIGURE 2-15:
Start-Up (MCP1252-33X50).
FIGURE 2-18:
Start-Up (MCP1253-33X50).
2002 Microchip Technology Inc.
DS21752A-page 7
MCP1252/3
3.6
Flying Capacitor Positive Terminal
(C+)
3.0
PIN FUNCTIONS
TABLE 3-1:
PIN FUNCTION TABLE
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.
Pin
Name
Function
No.
1
2
3
4
5
6
7
8
PGOOD Open-Drain Power GOOD Output
Regulated Output Voltage
V
OUT
3.7
Shutdown Input (SHDN)
Power Supply Input
V
IN
GND
C-
C+
Ground Terminal
A logic-low signal applied to SHDN disables the device.
A logic-high signal applied to this pin allows normal
operation.
Flying Capacitor Negative Terminal
Flying Capacitor Positive Terminal
SHDN Shutdown Mode, Active-Low Input
3.8
Select (SELECT) Input or
Feedback (FB) Input
Output Voltage Select Pin.
(MCP1252-33X50, MCP1253-33X50)
SELECT
MCP1252-33X50, MCP1253-33X50:
Feedback Input Pin for Adjustable Output
(MCP1252-ADJ, MCP1253-ADJ)
FB
SELECT: Select Input Pin.
Connect SELECT to V for 3.3V fixed output. Connect
IN
3.1
Open-Drain Power Good Output
(PGOOD)
SELECT to GND for a 5.0V fixed output.
MCP1252-ADJ, MCP1253-ADJ:
FB: Feedback Pin.
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
A resistor divider connected to this pin determines the
adjustable V
value (1.5V to 5.5V).
OUT
output remains low until V
is within 3% (typical) of
OUT
its nominal value. On start-up, this pin indicates when
the output voltage reaches its final value. PGOOD is
high-impedance when SHDN is low.
3.2
Regulated Output Voltage (V
)
OUT
Bypass to GND with a filter capacitor.
3.3
Power Supply Input (V )
IN
It is recommended that V be tied to a ceramic bypass
IN
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
Terminal (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.
MCP1252/3
4.0
4.1
DEVICE OVERVIEW
Theory of Operation
START
The MCP1252 and MCP1253 family of devices employ
a switched capacitor charge pump to buck or boost an
PHASE 1:
input supply voltage (V ) to a regulated output voltage.
Charge Transfer
From VIN to CFLY
IN
Referring to the Functional Block Diagram and
Figure 4-1, the devices perform conversion and regula-
tion in three phases. When the devices are not in shut-
down mode and a steady-state condition has been
reached, the three phases are continuously cycled
through. The first phase transfers charge from the input
1
No
t1 = 2FOSC
to the flying capacitor (C ) connected to pins C+ and
Yes
FLY
C-. This phase always occurs for half of the internal
PHASE 2:
oscillator period. During this phase, switches S and S
1
2
Idle State
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 volt-
age is below the regulation point, the device transitions
to the third phase.
Yes
Yes
V
FB > VREF
No
The third phase transfers energy from the flying capac-
PHASE 3:
itor to the output capacitor connected to V
and the
OUT
Charge Transfer
From CFLY to COUT
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.
1
t3 = 2FOSC
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 conver-
sion. This is especially true for battery-operated appli-
cations that require a fixed output above or below the
input.
No
No
VFB > VREF
Yes
FIGURE 4-1:
Flow Algorithm.
2002 Microchip Technology Inc.
DS21752A-page 9
MCP1252/3
4.2
Power Efficiency
4.6
Thermal Shutdown
The power efficiency, η, is determined by the mode of
operation. In boost mode, the efficiency is approxi-
mately half of a linear regulator. In buck mode, the effi-
ciency 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.
The MCP1252 and MCP1253 feature thermal shut-
down with temperature hysteresis. When the die tem-
perature 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 out-
put.
EQUATION
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.
POUT
-------------
PIN
V
OUT × IOUT
V
------------------------------------
-------O---U----T---
ηBOOST
=
=
=
V
IN × 2 × IOUT
VIN × 2
P
V
× IOUT
-----O---U----T------------------- ----O----U----T-
=
V
VIN
-----O---U----T-
ηBUCK
=
=
PIN
V
IN × IOUT
SELECTABLE OUTPUT VOLTAGE
MCP1252-33X50
6
C+
+5.0V ±2.5%
2
VOUT
CFLY
4.3
Shutdown Mode
+
5
3
C-
COUT
RPU
2.7V to 5.5V
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.
VIN
1
8
+
PGOOD
SELECT
CIN
PGOOD Flag
To PICmicro®
Microcontroller
7
SHDN
GND
ON
4
OFF
CFLY = 1 µF
4.4
PGOOD Output
Shutdown
Control
C
C
R
IN = 10 µF
The PGOOD output is an open-drain output that sinks
OUT = 10 µF
PU = 100 kΩ
current when the regulator output voltage falls below
0.93V
(typical). The output voltage can either be
OUT
FIGURE 5-1:
Typical Circuit Configuration
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
for Fixed Output Device.
ADJUSTABLE OUTPUT VOLTAGE
the regulator output voltage falls below 0.93V
(typ-
OUT
MCP1252-ADJ
6
5
ical) for less than 200 µsec and then recovers, glitch-
immunity circuits prevent the PGOOD signal from tran-
sitioning low. A 10 kΩ to 1 MΩ pull-up resistor from
C+
+4.0V
2
VOUT
CFLY
+ COUT
RPU
R1
C-
2.7V to 5.5V
PGOOD to V
may be used to provide a logic output.
OUT
3
7
Connect PGOOD to GND or leave unconnected if not
used.
VIN
1
8
+
PGOOD
CIN
PGOOD Flag
To PICmicro®
Microcontroller
FB
4.5
Soft-Start and Short-Circuit
Protection
SHDN
GND
4
ON
R2
OFF
C
C
C
R
FLY = 1 µF
IN = 10 µF
The MCP1252 and MCP1253 features foldback short-
circuit 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.
Shutdown
Control
OUT = 10 µF
PU = 100 kΩ
VOUT = 1.21V (1 + R1/R2)
R1 = 23.2 kΩ
R2 = 10 kΩ
FIGURE 5-2:
Typical Circuit Configuration
for Adjustable Output Device.
DS21752A-page 10
2002 Microchip Technology Inc.
MCP1252/3
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%.
5.1
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)
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 perfor-
mance. Figure 5-3 depicts the recommended board
capacitors be used for both C and C
. These
OUT
IN
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 is very low, up to several
IN
megahertz, C may not be required. Alternatively, a
IN
somewhat smaller value of C may be substituted for
IN
layout. The input capacitor connected between V and
IN
the recommended 10 µF, but will not be as effective in
GND, and the output capacitor connected between
preventing ripple on the V pin.
IN
V
and GND, are 10 µF ceramic, X7R dielectric, in
OUT
The value of C
age ripple present on V
controls the amount of output volt-
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.
OUT
. Increasing the size of
OUT
C
will reduce output ripple at the expense of a
OUT
slower turn-on time from shutdown and a higher in-rush
current.
The flying capacitor (C ) controls the strength of the
PGOOD
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 maxi-
mum output current and efficiency.
VOUT
SELECT
SHDN
C+
GND
VIN
C-
5.2
Output Voltage Setting
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
FIGURE 5-3:
Recommended Printed
Circuit Board Layout.
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 adjust-
able output, connect a resistor between V
and FB
OUT
(R ) and another resistor between FB and GND (R ). In
1
2
the following equation, choose R to be less than or
2
equal to 30 kΩ and calculate R from the following
1
formula:
EQUATION
R
= R [(V
⁄ V ) – 1]
OUT FB
1
2
and
EQUATION
V
= V (1 + R ⁄ R )
FB
OUT
1
2
where:
VOUT is the desired output voltage from 1.5V to 5.5V
VFB is the internal regulation voltage, nominally 1.21V
2002 Microchip Technology Inc.
DS21752A-page 11
MCP1252/3
6.0
TYPICAL APPLICATION CIRCUITS
Single Cell Lithium-Ion Battery To 5V Converter
1 µF
5
6
C-
C+
3
7
1
2
8
4
VIN
VOUT
5V
10 µF
Single
Li-Ion
Cell
10 µF
+
-
SHDN
SELECT
GND
100 kΩ
PGOOD
MCP1252-33X50
White LED Bias
1 µF
5
6
C-
C+
UP TO 6 WHITE LEDS
3
2
VIN
VOUT
10 µF
Single
Li-Ion
Cell
10 µF
+
-
7
1
8
4
SHDN
PGOOD
SELECT
GND
100 kΩ
59 Ω 59 Ω 59 Ω 59 Ω 59 Ω 59 Ω
MCP1252-ADJ
PWM Contrast
Control
Alternative White LED Bias
1 µF
5
6
C-
C+
UP TO 6 WHITE LEDS
3
7
1
2
8
4
VIN
VOUT
24 kΩ
10 kΩ
10 µF
Single
Li-Ion
Cell
10 µF
+
-
SHDN
PGOOD
SELECT
GND
100 kΩ
10 Ω 10 Ω 10 Ω 10 Ω 10 Ω 10 Ω
MCP1252-ADJ
PWM Contrast
Control
DS21752A-page 12
2002 Microchip Technology Inc.
MCP1252/3
7.0
7.1
PACKAGING INFORMATION
Package Marking
Example:
8-Lead MSOP (Fixed)
1252SX
XXXXX
233025
YWWNNN
Example:
8-Lead MSOP (Adjustable)
1253DJ
XXXXX
233025
YWWNNN
Legend: XX...X Customer specific information*
YY
WW
NNN
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
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
A2
A
c
φ
A1
(F)
L
β
Units
Dimension Limits
INCHES
NOM
MILLIMETERS*
NOM
MIN
MAX
MIN
MAX
n
p
Number of Pins
Pitch
8
8
.026
0.65
Overall Height
A
A2
A1
E
E1
D
L
F
φ
.044
1.18
Molded Package Thickness
Standoff
.030
.034
.038
.006
.200
.122
.122
.028
.039
0.76
0.05
0.86
0.97
0.15
.5.08
3.10
3.10
0.70
1.00
§
.002
.184
.114
.114
.016
.035
Overall Width
Molded Package Width
Overall Length
Foot Length
Footprint (Reference)
Foot Angle
.193
.118
.118
.022
.037
4.90
3.00
3.00
0.55
0.95
4.67
2.90
2.90
0.40
0.90
0
6
0
6
c
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
.004
.010
.006
.012
.008
.016
0.10
0.25
0.15
0.30
0.20
0.40
B
α
β
7
7
7
7
*Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254mm) per side.
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.
Examples:
PART NO.
Device
X
/XX
a)
MCP1252-33X50I/MS: Low Noise, Positive-
Regulated Charge Pump, Fixed Output
MCP1252-ADJI/MS: Low Noise, Positive-
Regulated Charge Pump, Adjustable
Output
MCP1252T-33X50I/MS: Tape and Reel,
Low Noise, Positive-Regulated Charge
Pump, Fixed Output
Temperature Package
Range
b)
Device:
MCP1252: Low Noise, Positive-Regulated Charge Pump
MCP1252T: Low Noise, Positive-Regulated Charge Pump
(Tape and Reel)
c)
MCP1253: Low Noise, Positive-Regulated Charge Pump
MCP1253T: Low Noise, Positive-Regulated Charge Pump
(Tape and Reel)
a)
b)
MCP1253-33X50I/MS: Low Noise, Posi-
tive-Regulated Charge Pump, Fixed Output
MCP1253-ADJI/MS:
Low Noise, Posi-
Temperature Range:
Package:
I
=
=
-40°C to +85°C
tive-Regulated Charge Pump, Adjustable
Output
MCP1253T-ADJI/MS: Tape and Reel,
Low Noise, Positive-Regulated Charge
Pump, Adjustable Output
MS
Plastic Micro Small Outline (MSOP), 8-lead
c)
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom-
mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office
2. The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277
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 knowl-
edge, 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 com-
ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con-
veyed, implicitly or otherwise, under any intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, KEELOQ,
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 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.
2002 Microchip Technology Inc.
DS21752A - page 17
M
WORLDWIDE SALES AND SERVICE
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11/15/02
DS21752A-page 18
2002 Microchip Technology Inc.
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