MAX1595EUA50+ [MAXIM]
Regulated 3.3V/5.0V Step-Up/Step-Down Charge Pump; 稳定的3.3V / 5.0V升压/降压型电荷泵
| 型号： | MAX1595EUA50+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Regulated 3.3V/5.0V Step-Up/Step-Down Charge Pump |
| 文件： | 总7页 (文件大小：192K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2107; Rev 2; 6/09
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
General Description
Features
The MAX1595 charge-pump regulator generates either
3.3V or 5V from a 1.8V to 5.5V input. The unique control
architecture allows the regulator to step up or step
down the input voltage to maintain output regulation.
The 1MHz switching frequency, combined with a
unique control scheme, allows the use of a ceramic
capacitor as small as 1µF for 125mA of output current.
The complete regulator requires three external capaci-
tors—no inductor is needed. The MAX1595 is specifi-
cally designed to serve as a high-power, high-
efficiency auxiliary supply in applications that demand
a compact design. The MAX1595 is offered in space-
saving 8-pin µMAX and high-power 12-pin thin QFN
packages.
♦ Ultra-Small: Requires Only Three Ceramic
Capacitors
♦ No Inductors Required
♦ Up to 125mA Output Current
♦ Regulated ±±3 Output ꢀoltage
♦ 1MHz Switching Frequency
♦ 1.8ꢀ to 5.5ꢀ Input ꢀoltage
♦ 220µA Quiescent Current
♦ 0.1µA Shutdown Current
♦ Load Disconnect in Shutdown
Applications
Ordering Information
White LED Power
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
Flash Memory Supplies
MAX1595EUA33+
MAX1595ETC33+
MAX1595EUA50+
Battery-Powered Applications
Miniature Equipment
12 Thin QFN-EP*
8 µMAX
PCMCIA Cards
MAX1595ETC50+
12 Thin QFN-EP*
3.3V to 5V Local Conversion Applications
Backup-Battery Boost Converters
3V to 5V GSM SIMM Cards
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Selector Guide
PART
ꢀ
OUT
(ꢀ)**
TOP MARK
UDAA
AAEH
MAX1595EUA33+
MAX1595ETC33+
MAX1595EUA50+
3.3
3.3
5.0
5.0
UJAN
Typical Operating Circuit
MAX1595ETC50+
AAEI
**Contact factory for other fixed-output voltages from 2.7V to 5.0V.
Pin Configurations
CXN
CXP
TOP VIEW
MAX1595
INPUT
OUTPUT
IN
OUT
AOUT
AOUT
SHDN
IN
1
2
3
4
8
7
6
5
OUT
SHDN
CXP
MAX1595
CXN
PGND
PGND GND
GND
μMAX
Pin Configurations continued at end of data sheet.
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
ABSOLUTE MAXIMUM RATINGS
IN, OUT, AOUT to GND............................................-0.3V to +6V
SHDN to PGND ........................................................-0.3V to +6V
PGND to GND .......................................................-0.3V to +0.3V
CXN to PGND.....................-0.3V to (Lower of IN + 0.8V or 6.3V)
CXP to GND ................................-0.8V to (Higher of OUT + 0.8V
or IN + 0.8V but not greater than 6V)
Continuous Power Dissipation (T = +70°C)
A
8-Pin µMAX (derate 4.5mW/°C above +70°C)............362mW
12-Pin Thin QFN (derate 18.5mW/°C
above +70°C)............................................................1481mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Continuous Output Current...............................................150mA
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V = 2V for MAX1595_ _ _33, V = 3V for MAX1595_ _ _50, C = 1µF, C = 0.22µF, C
= 1µF, T = -40° to +85°C, unless otherwise
A
IN
IN
IN
X
OUT
noted. Typical values are at T = +25°C.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
V
1.8
5.5
V
IN
Input Undervoltage Lockout
Threshold
1.40
1.60
1.72
V
Input Undervoltage Lockout
Hysteresis
40
mV
T
T
T
T
T
T
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
= 0°C to +85°C
= -40°C to +85°C
4.85
4.80
3.20
3.16
3.20
3.16
5.05
5.15
5.20
3.40
3.44
3.40
3.44
320
350
1.15
5
0 < I
< 125mA,
A
A
A
A
A
A
LOAD
V
= +3.0V
IN
3.33
3.33
0 < I
= +2.0V
< 75mA, V
< 30mA, V
LOAD
IN
IN
Output Voltage
V
V
OUT
0 < I
= +1.8V
LOAD
V
V
= +2.0V, MAX1595_ _ _33
= +3.0V, MAX1595_ _ _50
220
240
1.0
IN
No-Load Input Current
I
µA
Q
IN
Switching Frequency
f
I
> 20mA, V
> V
IN
0.85
1.6
MHz
µA
V
OSC
LOAD
OUT
Shutdown Supply Current
SHDN Input Voltage Low
SHDN Input Voltage High
SHDN Input Leakage Current
I
V
V
V
= 0V, V = +5.5V, V
= 0V
SHDN
SHDN
IN
OUT
V
= 2.0V to 5.5V
= 2.0V to 5.5V
0.6
INL
IN
IN
V
V
INH
0.1
µA
Note 1: Specifications to -40°C are guaranteed by design, not production tested.
2
_______________________________________________________________________________________
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
__________________________________________Typical Operating Characteristics
(Circuit of Figure 4, V = 2V for MAX1595_ _ _33, V = 3V for MAX1595_ _ _50, T = +25°C, unless otherwise noted.)
IN
IN
A
OUTPUT VOLTAGE
vs. LOAD CURRENT
NO LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
OUTPUT WAVEFORM
MAX1595 toc02
5.06
10000
5.04
5.02
5.00
V
= 3.6V
IN
1000
100
10
V
= 3.3V
IN
4.98
4.96
V
= 3V
IN
4.94
4.92
4.90
1
V
= 5V
OUT
V
= 5V
V
= 5V
OUT
OUT
0.1
6
200ns/div
OUTPUT WAVEFORM. AC-COUPLED.
= 3.6V, I = 100mA, C = 1μF
1000
0
1
2
3
4
5
1
10
100
SUPPLY VOLTAGE (V)
LOAD CURRENT (mA)
V
IN
LOAD
OUT
5V EFFICIENCY
vs. LOAD CURRENT
3V EFFICIENCY
vs. LOAD CURRENT
SHUTDOWN TIMING
MAX1595 toc06
100
100
V
= 1.8V
IN
90
80
70
60
50
40
30
20
90
80
70
60
50
40
30
20
10
0
V
= 3V
IN
5V
A
B
V
IN
= 3.3V
V
= 2.4V
IN
V
= 3.6V
IN
10
0
0.1
1
10
100
1000
100μs/div
1
10
LOAD CURRENT (mA)
100
A: OUTPUT VOLTAGE: R = 100Ω, 2V/div
LOAD CURRENT (mA)
L
B: SHDN VOLTAGE: 2V/div
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
LOAD-TRANSIENT RESPONSE
LINE-TRANSIENT RESPONSE
MAX1595 toc08
MAX1595 toc07
6
5
4
3
V
= 5V, I
= 125mA
LOAD
OUT
A
A
B
V
= 3.3V, I
= 75mA
OUT
LOAD
2
1
0
B
C
= 1μF
OUT
200μs/div
A: LOAD CURRENT: I = 5mA to 95mA, 100mA/div
B: OUTPUT VOLTAGE: AC-COUPLED 100mV/div
2ms/div
A: INPUT VOLTAGE: V = 3.1V TO 3.6V, 500mV/div
3
4
5
2
0
1
6
LOAD
IN
SUPPLY VOLTAGE (V)
B: OUTPUT VOLTAGE: I
= 50mA, 100mV/div
LOAD
_______________________________________________________________________________________
3
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
Pin Description
PIN
NAME
FUNCTION
MAX1595
µMAX
MAX1595
THIN QFN-EP
Analog Power and Sense Input for Error Amplifier/Comparator. Connect to OUT at
output filter capacitor.
1
2
12
AOUT
Shutdown Input. When SHDN = low, the device turns off; when SHDN = high, the device
activates. In shutdown, OUT is disconnected from IN.
MAX195
1
SHDN
3
4
5
6
7
8
2, 3
4
IN
Input Supply. Can range from 1.8V to 5.5V. Bypass to GND with a 1µF capacitor.
Ground
GND
PGND
CXN
CXP
5, 6
7, 8
9
Power Ground
Negative Terminal of the Charge-Pump Transfer Capacitor
Positive Terminal of the Charge-Pump Transfer Capacitor
Output. Bypass to GND with output capacitor filter.
10, 11
OUT
Exposed Pad. Internally connected to GND. Connect to a large ground plane to
maximize thermal performance. Not intended as an electrical connection point (thin
QFN package only).
—
—
EP
Detailed Description
S2
IN
OUT
The MAX1595 charge pump provides either a 3.3V or 5V
regulated output. It delivers a maximum 125mA load cur-
rent. In addition, to boost regulating from a lower supply,
it is also capable of buck regulating from supplies that
exceed the regulated output by a diode drop or more.
Designed specifically for compact applications, a com-
plete regulator circuit requires only three small external
capacitors. An innovative control scheme provides con-
stant frequency operation from medium to heavy loads,
while smoothly transitioning to low-power mode at light
loads to maintain optimum efficiency. In buck mode,
switch S1 (in Figure 1) is switched continuously to IN,
while switch S2 alternates between IN and OUT. An
amount of charge proportional to the difference between
the output voltage and the supply voltage is stored on
C
X
S1
C
IN
C
OUT
OSC
Figure 1. Unregulated Voltage Doubler
than doubling the input voltage, the MAX1595 provides a
regulated output voltage of either 3.3V or 5.0V.
C , which gets transferred to the output when the regula-
X
tion point is reached. Maximum output ripple is propor-
tional to the difference between the supply voltage and
the output voltage, as well as to the ratio of the transfer
Shutdown
Driving SHDN low places the device in shutdown mode.
The device draws 0.1µA of supply current in this mode.
When driven high, the MAX1595 enters a soft-start
mode. Soft-start mode terminates when the output volt-
age regulates, or after 2ms, whichever comes first. In
shutdown, the output disconnects from the input.
capacitor (C ) to the output capacitor (C
).
X
OUT
The MAX1595 consists of an error amplifier, a 1.23V
bandgap reference, internal resistive feedback network,
oscillator, high-current MOSFET switches, and shutdown
and control logic. Figure 1 shows an idealized unregulat-
ed charge-pump voltage doubler. The oscillator runs at a
50% duty cycle. During one half of the period, the trans-
fer capacitor (C charges to the input voltage. During
X)
the other half, the doubler transfers the sum of CX and
input voltage to the output filter capacitor (COUT). Rather
Undervoltage Lockout
The MAX1595 has an undervoltage-lockout that deacti-
vates the devices when the input voltage falls below 1.6V.
Below UVLO, hysteresis holds the device in shutdown until
the input voltage rises 40mV above the lockout threshold.
4
_______________________________________________________________________________________
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
Applications Information
C
X
= 0.1μF
Using white LEDs to backlight LCDs is an increasingly
popular approach for portable information devices
(Figure 2). Because the forward voltage of white LEDs
exceeds the available battery voltage, the use of a
charge pump such as the MAX1595 provides high effi-
ciency, small size, and constant light output with chang-
ing battery voltages. If the output is used only to light
LEDs, the output capacitor can be greatly reduced. The
frequency modulation of the LED intensity is not dis-
cernible to the human eye, and the smaller capacitor
saves both size and cost.
CXP
CXN
MAX1595_ _ _50
IN
V
IN
OUT
AOUT
SHDN
C
=
OUT
C
IN
= 1μF
0.47μF
100Ω
100Ω
100Ω
PGND GND
Adding two Schottky diodes and two capacitors imple-
ments a tripler and allows the MAX1595_ _ _50 to regu-
late a current of 75mA with a supply voltage as low as
2.3V (Figure 3).
Figure 2. White LED Bias Supply
Capacitor Selection
The MAX1595 requires only three external capacitors
(Figure 4). Their values are closely linked to the output
current capacity, oscillator frequency, output noise con-
tent, and mode of operation.
Generally, the transfer capacitor (C ) will be the smallest,
X
INPUT
2.3V
IN
AOUT
OUT
and the input capacitor (C ) is twice as large as C .
IN
X
OUTPUT
Higher switching frequencies allow the use of the smaller
SHDN
REGULATED 5V
75mA
C
and C . The output capacitor (C
) can be any-
X
IN
OUT
1μF
1μF
0.22μF
1μF
where from 5-times to 50-times larger than C . Table 1
X
MAX1595_ _ _50
CXP
shows recommended capacitor values.
0.22μF
In addition, the following equation approximates output
ripple:
CXN
PGND GND
V
≅ I
/ (2 x f
x C
)
RIPPLE OUT
OSC
OUT
Table 2 lists the manufacturers of recommended capaci-
tors. Ceramic capacitors will provide the lowest ripple
due to their typically lower ESR.
Figure 3. Regulated Voltage Tripler
Power Dissipation
The power dissipated in the MAX1595 depends on out-
put current and is accurately described by:
7
6
P
= I
(2V - V
)
CXP
CXN
DISS
OUT
IN
OUT
2
3
ON
C
X
SHDN
IN
OFF
0.22μF
P
must be less than that allowed by the package
DISS
rating.
IN
MAX1595
8
1
OUT
OUT
Layout Considerations
AOUT
C
IN
1μF
PGND
GND
4
All capacitors should be soldered in close proximity to
the IC. Connect ground and power ground through a
short, low-impedance trace. The input supply trace
should be as short as possible. Otherwise, an additional
input supply filter capacitor (tantalum or electrolytic) may
be required.
C
OUT
5
1μF
Figure 4. Standard Operating Circuit
_______________________________________________________________________________________
5
Regulated 3.3V/5.0V Step-Up/Step-Down
Charge Pump
Table 1. Recommended Capacitor Values
OUTPUT RIPPLE (mV)
C
IN
(µF)
C
(µF)
C
(µF)
OUT
X
70
35
1
0.22
0.47
1
2.2
2.2
MAX195
Table 2. Recommended Capacitor Manufacturers
VALUE (µF)
VOLTAGE (V)
TYPE
X7R
X7R
X7R
X7R
SIZE
0805
0603
0603
0603
MANUFACTURER
PART
1
10
10
10
10
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
LMK212BJ105MG
LMK107BJ224MA
LMK107BJ474MA
LMK107BJ104MA
0.22
0.47
0.1
Chip Information
Pin Configurations (continued)
PROCESS: CMOS
TOP VIEW
AOUT
12
OUT
11
OUT
10
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package draw-
ings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
SHDN
1
9
CXP
IN
IN
2
3
8
7
CXN
CXN
MAX1595
PACKAGE TYPE PACKAGE CODE
DOCUMENT NO.
21-0036
8 µMAX
U8+1
4
5
6
12 Thin QFN
1244+4
21-0139
GND PGND PGND
THIN QFN
4mm × 4mm
6
_______________________________________________________________________________________
Regulated 3.3V/5.0V Step-Up/Down
Charge Pump
MAX195
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
2
6/09
Added EP (exposed pad) and top mark information
1, 2, 4, 6
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7
© 2009 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
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