19-2954; Rev 2; 8/05
KIT
ATION
EVALU
BLE
AVAILA
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
General Description
Features
♦
Up to 4MHz PWM Switching Frequency
♦
500mA Guaranteed Output Current
♦
40µA (typ) Quiescent Current
♦
Adjustable Output Voltage from 0.6V to 2.5V
♦
Logic-Controlled Output Voltage (MAX8561)
♦
Drives External Bypass FET (MAX8562)
♦
±1.5% Initial Accuracy
♦
Soft-Start Eliminates Inrush Current
♦
Fast Voltage-Positioning Transient Response
♦
Internal Synchronous Rectifier
♦
2.7V to 5.5V Input
♦
0.1µA Logic-Controlled Shutdown
♦
Thermal Shutdown
♦
Thin SOT23 or Space-Saving 3mm x 3mm x
0.8mm TDFN Packages
MAX8560/MAX8561/MAX8562
The MAX8560/MAX8561/MAX8562 step-down DC-DC
converters are optimized for applications that prioritize
small size and high efficiency. They utilize a proprietary
hysteretic-PWM control scheme that switches with fixed
frequency and is adjustable up to 4MHz, allowing cus-
tomers to trade efficiency for smaller external compo-
nents. Output current is guaranteed up to 500mA, while
quiescent current is only 40µA (typ).
Internal synchronous rectification greatly improves effi-
ciency and eliminates the external Schottky diode
required in conventional step-down converters. Built-in
soft-start eliminates inrush current to reduce input
capacitor requirements. The MAX8561 features logic-
controlled output voltage, while the MAX8562 drives an
external bypass FET.
The MAX8560 is available in a 5-pin Thin SOT23 pack-
age. The MAX8561/MAX8562 are available in space-
saving 8-pin 3mm x 3mm Thin DFN packages.
Applications
Microprocessor/DSP Core Supplies
Cellular and Smart Phones
CDMA/RF Power-Amplifier Supplies
PDAs, DSC, and MP3 Players
PART
MAX8560EZK-T
MAX8560EZK+T
MAX8561ETA-T
MAX8561ETA+T
MAX8562ETA-T
MAX8562ETA+T
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
5 Thin SOT23-5
5 Thin SOT23-5
8 TDFN
8 TDFN
8 TDFN
8 TDFN
TOP
MARK
ADRX
ADRX
AHD
AHD
AHE
AHE
+Denotes lead-free package.
Typical Operating Circuit
TOP VIEW
INPUT
2.7V TO 5.5V
C
IN
2.2µF
IN
GND
MAX8560
LX
R1
C
OUT
2.2µF
C
FF
SHDN 3
4 FB
GND 2
Pin Configurations
SHDN
GND
L
1µH
OUTPUT
0.6V TO 2.5V
UP TO 500mA
8
IN
1
5 LX
7
6
MAX8560
MAX8561/
MAX8562
1
IN
2
PGND
3
LX
4
ODI
FB
ON/OFF
SHDN
R2
Thin SOT23-5
TDFN
3mm
×
3mm
×
0.8mm
A "+" sign will replace the first pin indicator
on lead-free packages.
________________________________________________________________
Maxim Integrated Products
ODO
FB
5
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
MAX8560/MAX8561/MAX8562
ABSOLUTE MAXIMUM RATINGS
IN, FB,
SHDN,
ODI, ODO to GND ............................-0.3V to +6V
LX to GND (Note 1)......................................-0.3V to (V
IN
+ 0.3V)
PGND to GND .......................................................-0.3V to +0.3V
LX Current ...........................................................................1.27A
Output Short Circuit to GND
(typical operating circuit)....................................................10s
Continuous Power Dissipation (T
A
= +70°C)
5-Pin Thin SOT23 (derate 9.1mW/°C above +70°C) ....727mW
8-Pin TDFN (derate 24.4mW/°C above +70°C) .........1951mW
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
Note 1:
LX has internal clamp diodes to PGND (GND for MAX8560) and IN. Applications that forward bias these diodes should take
care not to exceed the IC’s package power-dissipation limits.
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
IN
= 3.6V,
SHDN
= IN, T
A
= -40°C to +85°C, typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage Range
UVLO Threshold
Supply Current
Output Voltage Range
FB Threshold Voltage
FB Threshold Line Regulation
FB Threshold Load Regulation
FB Threshold Voltage Accuracy
(Falling) (% of V
FB
)
FB Threshold Voltage Hysteresis
(% of V
FB
)
V
HYS
SHDN
= GND, T
A
= +25°C, V
IN
= 5.5V
FB Bias Current
I
FB
SHDN
= GND, T
A
= +85°C, V
IN
= 5.5V
V
FB
= 0.5V, T
A
= +25°C, V
IN
= 5.5V
V
FB
= 0.5V, T
A
= +85°C, V
IN
= 5.5V
Logic Input High Voltage
(SHDN, ODI)
Logic Input Low Voltage
(SHDN, ODI)
V
IH
V
IL
V
IN
= 2.7V to 5.5V
V
IN
= 2.7V to 5.5V
V
IN
= 5.5V,
SHDN
= ODI = GND or IN,
T
A
= +25°C
V
IN
= 5.5V,
SHDN
= ODI = GND or IN,
T
A
= +85°C
1mA sink current, V
IN
= 2.7V
0.001
0.01
0.02
0.1
V
1.41
V
0.4
0.1
µA
SYMBOL
V
IN
UVLO
I
IN
V
OUT
V
FB
V
FB
falling
V
IN
= 2.7V to 5.5V
I
OUT
= 0 to 500mA
I
LOAD
= 0mA
T
A
= +25°C
T
A
= -40°C to +85°C
-1.5
-2.5
1.0
0.01
0.1
0.01
0.1
0.1
0.1
µA
V
IN
rising, 60mV hysteresis
I
LOAD
= 0mA, no switching
SHDN
= GND
T
A
= +25°C
T
A
= +85°C
0.6
0.6
0.3
-0.001
+1.5
+2.5
CONDITIONS
MIN
2.7
2.4
2.5
40
0.01
0.1
2.5
V
V
%/V
%/mA
%
%
TYP
MAX
5.5
2.6
80
0.1
µA
UNITS
V
V
Logic Input Bias Current
I
IH
, I
IL
ODO Output Low Voltage
(MAX8562 Only)
V
OL
2
_______________________________________________________________________________________
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.6V,
SHDN
= IN, T
A
= -40°C to +85°C, typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
ODO Pullup to IN (MAX8562 Only)
Open-Drain Output Leakage
Current Limit
On-Resistance
Rectifier-Off Current Threshold
I
OHLEAK
I
LIMP
I
LIMN
R
ONP
R
ONN
I
LXOFF
V
IN
= 5.5V, LX = GND to IN, ODO = IN,
T
A
= +25°C,
SHDN
= GND
V
IN
= 5.5V, LX = GND to IN, ODO = IN,
T
A
= +85°C,
SHDN
= GND
V
IN
= 5.5V, ODO = IN, T
A
= +25°C
V
IN
= 5.5V, ODO = IN, T
A
= +85°C
PFET switch
NFET rectifier
PFET switch, I
LX
= -40mA
NFET rectifier, I
LX
= +40mA
0
600
490
SYMBOL
CONDITIONS
MIN
5
TYP
10
0.01
0.1
990
680
0.8
0.4
30
0.1
1
107
95
+160
20
ns
°C
°C
1500
900
1.5
0.82
60
1
µA
MAX
20
0.1
UNITS
kΩ
µA
mA
Ω
mA
MAX8560/MAX8561/MAX8562
LX Leakage Current
I
LXLKG
Minimum On- and Off-Times
Thermal Shutdown
Thermal-Shutdown Hysteresis
t
ON(MIN)
t
OFF(MIN)
Typical Operating Characteristics
(V
IN
= 3.6V, V
OUT
= 1.2V, L = 1µH (LQH32CN1R0M53), C
OUT
= 2.2µF, T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 2.5V)
MAX8560 toc01
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 1.8V)
MAX8560 toc02
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 1.5V)
MAX8560 toc03
100
4.7µH
90
2.2µH
EFFICIENCY (%)
80
70
60
50
40
0.1
1
10
100
1µH
100
90
EFFICIENCY (%)
80
2.2µH
70
60
50
40
1µH
4.7µH
100
90
EFFICIENCY (%)
80
2.2µH
70
60
50
40
1µH
4.7µH
1000
0.1
1
10
100
1000
0.1
1
10
100
1000
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
_______________________________________________________________________________________
3
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
MAX8560/MAX8561/MAX8562
Typical Operating Characteristics (continued)
(V
IN
= 3.6V, V
OUT
= 1.2V, L = 1µH (LQH32CN1R0M53), C
OUT
= 2.2µF, T
A
= +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 1.2V)
MAX8560 toc04
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 0.9V)
MAX8560 toc05
EFFICIENCY vs. LOAD CURRENT
(LOAD = 7.5Ω)
4.7µH
MAX8560 toc06
100
90
4.7µH
EFFICIENCY (%)
80
2.2µH
70
60
50
40
0.1
1
10
100
1µH
100
90
4.7µH
EFFICIENCY (%)
80
70
60
50
40
2.2µH
1µH
100
90
EFFICIENCY (%)
80
2.2µH
70
60
50
40
1µH
1000
0.1
1
10
100
1000
0.5
1.0
1.5
2.0
2.5
LOAD CURRENT (mA)
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
NO-LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX8560 toc07
SWITCHING FREQUENCY
vs. LOAD CURRENT
1µH
MAX8560 toc08
OUTPUT VOLTAGE vs. LOAD CURRENT
(VOLTAGE POSITIONING)
1.23
OUTPUT VOLTAGE (V)
1.22
1.21
1.20
1.19
1.18
1.17
MAX8560 toc09
47
46
SUPPLY CURRENT (µA)
45
44
43
42
41
40
R1 = R2 = 100kΩ
39
2.0
2.5
3.0
3.5
4.0
4.5
5.0
10
1.24
FREQUENCY (MHz)
2.2µH
1
4.7µH
R1 = R2 = 100kΩ
0.1
1.16
0
100
200
300
400
500
0
100
200
300
400
500
LOAD CURRENT (mA)
LOAD CURRENT (mA)
5.5
SUPPLY VOLTAGE (V)
LIGHT-LOAD SWITCHING WAVEFORMS
MAX8560 toc10
HEAVY-LOAD SWITCHING WAVEFORMS
MAX8560 toc11
50mA LOAD
V
OUT
20mV/div
I
L
200mA/div
0
200mA LOAD
V
OUT
20mV/div
I
L
200mA/div
0
V
LX
2V/div
V
LX
2V/div
200ns/div
200ns/div
4
_______________________________________________________________________________________
4MHz, 500mA Synchronous Step-Down
DC-DC Converters in Thin SOT and TDFN
MAX8560/MAX8561/MAX8562
Typical Operating Characteristics (continued)
(V
IN
= 3.6V, V
OUT
= 1.2V, L = 1µH (LQH32CN1R0M53), C
OUT
= 2.2µF, T
A
= +25°C, unless otherwise noted.)
LIGHT-LOAD SOFT-START WAVEFORMS
MAX8560 toc12
HEAVY-LOAD SOFT-START WAVEFORMS
MAX8560 toc13
LINE-TRANSIENT RESPONSE
MAX8560 toc14
100Ω LOAD
V
OUT
1V/div
I
IN
200mA/div
3Ω LOAD
V
OUT
1V/div
I
IN
200mA/div
5Ω LOAD
V
OUT
20mV/div
I
L
200mA/div
I
L
200mA/div
0
V
SHDN
2V/div
20µs/div
V
IN
= 3.5V
0
V
IN
= 4.0V
V
IN
500mV/div
I
L
200mA/div
0
V
SHDN
2V/div
20µs/div
2µs/div
LOAD-TRANSIENT RESPONSE
MAX8560 toc15
OUTPUT-VOLTAGE TRANSIENT RESPONSE
(MAX8561)
MAX8560 toc16
BYPASS-FET TRANSIENT RESPONSE
(MAX8562)
MAX8560 toc17
V
OUT
= 1.5V
V
OUT
50mV/div
I
L
500mA/div
0
500mA LOAD
I
LOAD
500mA/div
20mA LOAD
2µs/div
20mA LOAD
7.5Ω LOAD, L = 2.2µH
40µs/div
V
ODI
2V/div
7.5Ω LOAD
V
OUT
500mV/div
V
OUT
= 1.0V
I
L
200mA/div
0
V
OUT
= V
IN
V
OUT
2V/div
V
OUT
= 1.2V
0
I
L
500mA/div
0
V
ODI
2V/div
20µs/div
_______________________________________________________________________________________
5
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