MAX8640YEXT18+T [MAXIM]

Tiny 500mA, 4MHz/2MHz Synchronous Step-Down DC-DC Converters; 微小500毫安,为4MHz / 2MHz的同步降压型DC- DC转换器
MAX8640YEXT18+T
型号: MAX8640YEXT18+T
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

Tiny 500mA, 4MHz/2MHz Synchronous Step-Down DC-DC Converters
微小500毫安,为4MHz / 2MHz的同步降压型DC- DC转换器

转换器
文件: 总11页 (文件大小:311K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
19-3997; Rev 2; 7/07  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
General Description  
Features  
Tiny SC70 and µDFN Packages  
The MAX8640Y/MAX8640Z step-down converters are  
optimized for applications where small size, high effi-  
ciency, and low output ripple are priorities. They utilize  
a proprietary PWM control scheme that optimizes the  
switching frequency for high efficiency with small exter-  
nal components and maintains low output ripple volt-  
age at all loads. The MAX8640Z switches at up to  
4MHz to allow a tiny 1µH inductor and 2.2µF output  
capacitor. The MAX8640Y switches at up to 2MHz for  
higher efficiency while still allowing small 2.2µH and  
4.7µF components. Output current is guaranteed up to  
500mA, while typical quiescent current is 24µA.  
Factory-preset output voltages from 0.8V to 2.5V elimi-  
nate external feedback components.  
500mA Guaranteed Output Current  
4MHz or 2MHz PWM Switching Frequency  
Tiny External Components: 1µH/2.2µF or  
2.2µH/4.7µF  
24µA Quiescent Current  
Factory Preset Outputs from 0.8V to 2.5V  
1ꢀ ꢁnitial Accuracy  
Low Output Ripple at All Loads  
Ultrasonic Skip Mode Down to 1mA Loads  
Ultra-Fast Line- and Load-Transient Response  
Fast Soft-Start Eliminates ꢁnrush Current  
Ordering Information  
Internal synchronous rectification greatly improves effi-  
ciency and replaces the external Schottky diode  
required in conventional step-down converters. Internal  
fast soft-start eliminates inrush current so as to reduce  
input capacitor requirements.  
PꢁN-  
PKG  
TOP  
PART*  
PACKAGE  
CODE  
MARK  
ACQ  
ACR  
ACS  
ACG  
ADD  
ADB  
ACI  
MAX8640YEXT08+T 6 SC70-6  
MAX8640YEXT11+T 6 SC70-6  
MAX8640YEXT12+T 6 SC70-6  
MAX8640YEXT13+T 6 SC70-6  
MAX8640YEXT15+T 6 SC70-6  
MAX8640YEXT16+T 6 SC70-6  
MAX8640YEXT18+T 6 SC70-6  
MAX8640YEXT19+T 6 SC70-6  
MAX8640YEXT25+T 6 SC70-6  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
The MAX8640Y/MAX8640Z are available in the tiny 6-  
pin, SC70 (2.0mm x 2.1mm) and µDFN (1.5mm x  
1.0mm) packages. Both packages are lead-free.  
Applications  
Microprocessor/DSP Core Power  
I/O Power  
ACH  
ACJ  
Cell Phones, PDAs, DSCs, MP3s  
Other Handhelds Where Space Is Limited  
*Contact factory for availability of each version.  
+Denotes a lead-free package.  
T = Tape and reel.  
Note: All devices are specified over the -40°C to +85°C  
operating temperature range.  
Ordering Information continued and Selector Guide appears  
at end of data sheet.  
Typical Operating Circuit  
Pin Configurations  
TOP VIEW  
+
+
OUTPUT  
L1  
INPUT  
2.7V TO 4.9V  
0.8V TO 2.5V  
UP TO 500mA  
IN  
LX  
1
2
3
6
5
4
1
6
LX  
IN  
1μH OR 2.2μH  
IN  
LX  
MAX8640Y  
MAX8640Y  
MAX8640Z  
C1  
2.2μF  
GND  
GND  
OUT  
2
3
5
4
GND  
GND  
OUT  
MAX8640Y  
MAX8640Z  
GND  
OUT  
C2  
2.2μF OR  
4.7μF  
SHDN  
SHDN  
SHDN  
ON/OFF  
μDFN  
SC70  
1.5mm x 1.0mm  
2.0mm x 2.1mm  
________________________________________________________________ Maxim Integrated Products  
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.  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
ABSOLUTE MAXꢁMUM RATꢁNGS  
IN to GND.................................................................-0.3V to +6V  
6-Pin µDFN (derate 2.1mW/°C above +70°C) ..............167.7mW  
LX, OUT, SHDN to GND ..............................-0.3V to (V + 0.3V)  
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  
IN  
LX Current (Note 1) ........................................................0.8A  
RMS  
OUTPUT Short Circuit to GND ...................................Continuous  
Continuous Power Dissipation (T = +70°C)  
A
6-Pin SC70 (derate 3.1mW/°C above +70°C)..............245mW  
Note 1: LX has internal clamp diodes to IN and GND. Applications that forward bias these diodes should not exceed the IC’s package  
power-dissipation limit.  
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.  
ELECTRꢁCAL CHARACTERꢁSTꢁCS  
(V = 3.6V, SHDN = IN, T = -40°C to +85°C, typical values are at T = +25°C, unless otherwise noted.) (Note 2)  
IN  
A
A
PARAMETER  
SYMBOL  
CONDꢁTꢁONS  
MꢁN  
2.7  
TYP  
MAX UNꢁTS  
Supply Range  
V
4.9  
2.70  
48  
V
V
IN  
UVLO Threshold  
UVLO  
V
rising, 100mV hysteresis  
2.44  
2.6  
24  
IN  
No load, no switching  
Supply Current  
I
µA  
T
T
= +25°C  
= +85°C  
0.01  
0.1  
0.1  
CC  
A
SHDN = GND  
A
Output Voltage Range  
V
Factory preset  
0.8  
-1  
2.5  
+1  
+2  
V
OUT  
I
= 0mA, T = +25°C  
0
LOAD  
LOAD  
A
Output Voltage Accuracy  
(Falling Edge)  
%
I
= 0mA, T = -40°C to +85°C  
-2  
A
Output Load Regulation  
(Voltage Positioning)  
Equal to inductor DC resistance  
R
V/A  
V
L
V
V
V
= 2.7V to 4.9V  
= 2.7V to 4.9V  
1.4  
IH  
IN  
IN  
SHDN Logic Input Level  
V
0.4  
1
IL  
T
T
= +25°C  
= +85°C  
0.001  
0.01  
770  
650  
40  
A
V
= 4.9V,  
IN  
SHDN Logic Input Bias Current  
I
µA  
IH,IL  
SHDN = GND or IN  
A
Peak Current Limit  
I
pFET switch  
nFET rectifier  
nFET rectifier  
590  
450  
10  
1400  
1300  
70  
mA  
mA  
mA  
LIMP  
Valley Current Limit  
I
LIMN  
Rectifier Off-Current Threshold  
I
LXOFF  
R
pFET switch, I = -40mA  
0.6  
0.35  
0.1  
1
1.2  
0.7  
1
ONP  
ONN  
LX  
On-Resistance  
Ω
µA  
ns  
R
nFET rectifier, I = 40mA  
LX  
T
= +25°C  
= +85°C  
A
A
V
= 4.9V, LX = GND  
IN  
LX Leakage Current  
Minimum On and Off Times  
I
LXLKG  
to IN, SHDN = GND  
T
t
95  
ON(MIN)  
t
95  
OFF(MIN)  
Thermal Shutdown  
+160  
20  
°C  
°C  
Thermal-Shutdown Hysteresis  
Note 2: All devices are 100% production tested at T = +25°C. Limits over the operating temperature range are guaranteed by design.  
A
2
_______________________________________________________________________________________  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Typical Operating Characteristics  
(V = 3.6V, V  
= 1.5V, MAX8640Z, L = Murata LQH32CN series, T = +25°C, unless otherwise noted.)  
A
IN  
OUT  
NO-LOAD SUPPLY CURRENT  
vs. SUPPLY VOLTAGE  
SWITCHING FREQUENCY  
vs. LOAD CURRENT  
EFFICIENCY vs. LOAD CURRENT  
1.8V OUTPUT  
35  
30  
25  
20  
15  
10  
5
10  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
MAX8640YEXT18  
MAX8640YEXT18  
MAX8640ZEXT15  
MAX8640YEXT18  
1
MAX8640ZEXT15  
0.1  
2.9  
3.3  
3.7  
4.1  
4.5  
4.9  
0
100  
200  
300  
400  
500  
0.1  
1
10  
100  
1000  
SUPPLY VOLTAGE (V)  
LOAD CURRENT (mA)  
LOAD CURRENT (mA)  
LIGHT-LOAD SWITCHING WAVEFORMS  
(I = 1mA)  
OUTPUT VOLTAGE vs. LOAD CURRENT  
(VOLTAGE POSITIONING)  
OUT  
MAX8640Y/Z toc05  
1.55  
1.50  
1.45  
1.40  
1.35  
1.30  
20mV/div  
(AC-COUPLED)  
MAX8640ZEXT15  
V
OUT  
V
I
LX  
2V/div  
LX  
200mA/div  
0
100  
200  
300  
400  
500  
10μs/div  
LOAD CURRENT (mA)  
MEDIUM-LOAD SWITCHING WAVEFORMS  
(I = 40mA)  
HEAVY-LOAD SWITCHING WAVEFORMS  
(I = 300mA)  
OUT  
OUT  
MAX8640Y/Z toc06  
MAX8640Y/Z toc07  
20mV/div  
(AC-COUPLED)  
20mV/div  
(AC-COUPLED)  
V
V
OUT  
OUT  
2V/div  
0V  
V
I
LX  
LX  
V
I
LX  
2V/div  
0V  
200mA/div  
200mA/div  
0mA  
LX  
0mA  
200ns/div  
200ns/div  
_______________________________________________________________________________________  
3
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Typical Operating Characteristics (continued)  
(V = 3.6V, V  
= 1.5V, MAX8640Z, L = Murata LQH32CN series, T = +25°C, unless otherwise noted.)  
A
IN  
OUT  
LIGHT-LOAD STARTUP WAVEFORM  
HEAVY-LOAD STARTUP WAVEFORM  
(100Ω LOAD)  
(5Ω LOAD)  
MAX8640Y/Z toc08  
MAX8640Y/Z toc09  
5V/div  
5V/div  
V
SHDN  
V
SHDN  
1V/div  
0V  
1V/div  
0V  
V
OUT  
V
OUT  
100mA/div  
0mA  
100mA/div  
0mA  
I
IN  
I
IN  
500mA/div  
0mA  
I
LX  
I
500mA/div  
0mA  
LX  
20μs/div  
20μs/div  
LOAD-TRANSIENT RESPONSE  
LINE-TRANSIENT RESPONSE  
(5mA TO 250mA TO 5mA)  
(4V TO 3.5V TO 4V)  
MAX8640Y/Z toc11  
MAX8640Y/Z toc10  
50m/div  
AC-COUPLED  
1V/div  
4V  
V
IN  
V
OUT  
500mA/div  
I
LX  
V
OUT  
20mV/div  
AC-COUPLED  
200mA/div  
0mA  
I
OUT  
200mA/div  
0mA  
I
LX  
40μs/div  
20μs/div  
LOAD-TRANSIENT RESPONSE  
(10mA TO 500mA TO 10mA)  
MAX8640Y/Z toc12  
100mV/div  
V
OUT  
AC-COUPLED  
I
500mA/div  
0V  
LX  
I
OUT  
200mA/div  
40μs/div  
4
_______________________________________________________________________________________  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Pin Description  
PꢁN  
1
NAME  
LX  
FUNCTꢁON  
Inductor Connection to the Internal Drains of the p-channel and n-channel MOSFETs. High impedance  
during shutdown.  
2, 5  
3
GND  
OUT  
Ground. Connect these pins together directly under the IC.  
Output Sense Input. Bypass with a ceramic capacitor as close as possible to pin 3 (OUT) and pin 2 (GND).  
OUT is internally connected to the internal feedback network.  
Active-Low Shutdown Input. Connect to IN or logic-high for normal operation. Connect to GND or logic-low for  
shutdown mode.  
4
6
SHDN  
Supply Voltage Input. Input voltage range is 2.7V to 4.9V. Bypass with a ceramic capacitor as close as  
possible to pin 6 (IN) and pin 5 (GND).  
IN  
Detailed Description  
The MAX8640Y/MAX8640Z step-down converters deliv-  
er over 500mA to outputs from 0.8V to 2.5V. They utilize  
a proprietary hysteretic PWM control scheme that  
switches at up to 4MHz (MAX8640Z) or 2MHz  
(MAX8640Y), allowing some trade-off between efficien-  
cy and size of external components. At loads below  
100mA, the MAX8640Y/MAX8640Z automatically switch  
to pulse-skipping mode to minimize the typical quies-  
cent current (24µA). Output ripple remains low at all  
loads, while the skip-mode switching frequency  
remains ultrasonic down to 1mA (typ) loads. Figure 1 is  
the simplified functional diagram.  
IN  
PWM  
LOGIC  
SHDN  
LX  
GND  
OUT  
0.6V  
Control Scheme  
A proprietary hysteretic PWM control scheme ensures  
high efficiency, fast switching, fast transient response,  
low output ripple, and physically tiny external compo-  
nents. This control scheme is simple: when the output  
voltage is below the regulation threshold, the error  
comparator begins a switching cycle by turning on the  
high-side switch. This switch remains on until the mini-  
mum on-time expires and the output voltage is above  
the regulation threshold or the inductor current is above  
the current-limit threshold. Once off, the high-side  
switch remains off until the minimum off-time expires  
and the output voltage falls again below the regulation  
threshold. During the off period, the low-side synchro-  
nous rectifier turns on and remains on until either the  
high-side switch turns on again or the inductor current  
approaches zero. The internal synchronous rectifier  
eliminates the need for an external Schottky diode.  
MAX8640Y  
MAX8640Z  
Figure 1. Simplified Functional Diagram  
allowing the use of very small ceramic output capacitors.  
This configuration yields load regulation equal to the  
inductor’s series resistance multiplied by the load current.  
This voltage-positioning load regulation greatly reduces  
overshoot during load transients, effectively halving the  
peak-to-peak output-voltage excursions compared to tra-  
ditional step-down converters. See the Load-Transient  
Response in the Typical Operating Characteristics.  
Shutdown Mode  
Connecting SHDN to GND or logic low places the  
MAX8640Y/MAX8640Z in shutdown mode and reduces  
supply current to 0.1µA (typ). In shutdown, the control  
circuitry and internal MOSFET switches turn off and LX  
becomes high impedance. Connect SHDN to IN or  
logic high for normal operation.  
Voltage-Positioning Load Regulation  
The MAX8640Y/MAX8640Z utilize a unique feedback  
network. By taking DC feedback from the LX node, the  
usual phase lag due to the output capacitor is  
removed, making the loop exceedingly stable and  
_______________________________________________________________________________________  
5
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
It is acceptable to use a 1.5µH inductor with either the  
Soft-Start  
The MAX8640Y/MAX8640Z include internal soft-start  
circuitry that eliminates inrush current at startup, reduc-  
ing transients on the input source. Soft-start is particu-  
larly useful for higher impedance input sources, such  
as Li+ and alkaline cells. See the Soft-Start Response  
in the Typical Operating Characteristics.  
MAX8640Y or MAX8640Z, but efficiency and ripple  
should be verified. Similarly, it is acceptable to use a  
3.3µH inductor with the MAX8640Y, but performance  
should be verified.  
For optimum voltage positioning of load transients,  
choose an inductor with DC series resistance in the  
75mΩ to 150mΩ range. For higher efficiency at heavy  
loads (above 200mA) or minimal load regulation (but  
some transient overshoot), the resistance should be  
kept as low as possible. For light-load applications up  
to 200mA, higher resistance is acceptable with very lit-  
tle impact on performance.  
Applications Information  
The MAX8640Y/MAX8640Z are optimized for use with a  
tiny inductor and small ceramic capacitors. The correct  
selection of external components ensures high efficien-  
cy, low output ripple, and fast transient response.  
Inductor Selection  
A 1µH inductor is recommended for use with the  
MAX8640Z, and 2.2µH is recommended for the  
MAX8640Y. A 1µH inductor is physically smaller but  
requires faster switching, resulting in some efficiency  
loss. Table 1 lists several recommended inductors.  
Capacitor Selection  
Output Capacitor  
The output capacitor, C2, is required to keep the output  
voltage ripple small and to ensure regulation loop sta-  
bility. C2 must have low impedance at the switching fre-  
quency. Ceramic capacitors are recommended due to  
Table 1. Suggested ꢁnductors  
ꢁNDUCTANCE  
(µH)  
DC RESꢁSTANCE  
CURRENT RATꢁNG  
(mA)  
DꢁMENSꢁONS  
L x W x H (mm)  
MANUFACTURER  
SERꢁES  
(Ω typ)  
MIPFT2520D  
2.0  
1.5  
2.2  
3.3  
1.0  
1.5  
2.2  
1.2  
1.5  
2.2  
1.0  
1.5  
2.2  
1.0  
2.2  
1.0  
2.2  
1.0  
2.2  
1.0  
2.2  
1.0  
2.2  
0.16  
0.07  
0.08  
0.10  
0.12  
0.16  
0.22  
0.08  
0.09  
0.12  
0.11  
0.13  
0.14  
0.15  
0.36  
0.07  
0.10  
0.10  
0.20  
0.05  
0.08  
0.07  
0.14  
900  
1500  
1300  
1200  
1200  
1000  
900  
2.5 x 2.0 x 0.5  
2.5 x 2.0 x 1.0  
FDK  
MIPF2520D  
LQM31P  
Murata  
3.2 x 1.6 x 0.95  
3.0 x 3.0 x 1.0  
3.2 x 1.6 x 0.9  
590  
Sumida  
CDRH2D09  
CKP3216T  
520  
440  
1100  
1000  
900  
Taiyo Yuden  
460  
GLF201208T  
GLF2012T  
2.0 x 1.25 x 0.9  
2.0 x 1.25 x 1.35  
2.5 x 1.8 x 1.35  
2.5 x 2.0 x 1.0  
2.8 x 2.8 x 1.2  
300  
400  
TDK  
300  
800  
GLF251812T  
MDT2520-CR  
D2812C  
600  
1000  
700  
TOKO  
1100  
770  
6
_______________________________________________________________________________________  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
their small size and low ESR. Make sure the capacitor  
Input Capacitor  
The input capacitor, C1, reduces the current peaks  
drawn from the battery or input power source and  
reduces switching noise in the IC. The impedance of C1  
at the switching frequency should be kept very low.  
Ceramic capacitors are recommended due to their  
small size and low ESR. Make sure the capacitor main-  
tains its capacitance over temperature and DC bias.  
Capacitors with X5R or X7R temperature characteristics  
maintains its capacitance over temperature and DC  
bias. Capacitors with X5R or X7R temperature charac-  
teristics typically perform well. The output capacitance  
can be very low; see the Selector Guide for recom-  
mended capacitance values. For optimum load-tran-  
sient performance and very low output ripple, the output  
capacitor value in µF should be equal to or larger than  
the inductor value in µH.  
Selector Guide  
RECOMMENDED COMPONENTS  
TOP MARK  
OUTPUT  
VOLTAGE (V)  
FREQUENCY  
(MHz)  
PART  
C2 (µF)  
10  
L1 (µH)  
2.2  
MAX8640YEXT08  
MAX8640YEXT11  
MAX8640YEXT12  
MAX8640YEXT13  
MAX8640YEXT15  
MAX8640YEXT16  
MAX8640YEXT18  
MAX8640YEXT19  
0.8  
1.1  
1.2  
1.3  
1.5  
1.6  
1.8  
1.9  
1.2  
1.7  
1.8  
1.9  
2.0  
2.0  
2.0  
2.0  
ACQ  
ACR  
ACS  
ACG  
ADD  
ADB  
ACI  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
10  
2.2  
2.2  
2.2  
2.2  
2.2  
2.2  
2.2  
ACH  
MAX8640YEXT25  
MAX8640YELT08  
2.5  
0.8  
1.7  
1.2  
2.2  
2.2  
ACJ  
NB  
MAX8640YELT11  
MAX8640YELT12  
MAX8640YELT13  
MAX8640YELT15  
MAX8640YELT16  
MAX8640YELT18  
MAX8640YELT19  
MAX8640YELT25  
1.1  
1.2  
1.3  
1.5  
1.6  
1.8  
1.9  
2.5  
1.7  
1.8  
1.9  
2.0  
2.0  
2.0  
2.0  
1.7  
2.2  
2.2  
2.2  
2.2  
2.2  
2.2  
2.2  
2.2  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
2.2  
2.2  
2.2  
2.2  
2.2  
4.7  
2.2  
2.2  
2.2  
2.2  
2.2  
NC  
ND  
NE  
NF  
NG  
NH  
NI  
NJ  
MAX8640ZEXT08  
MAX8640ZEXT11  
MAX8640ZEXT12  
MAX8640ZEXT13  
MAX8640ZEXT15  
MAX8640ZEXT18  
MAX8640ZELT08  
MAX8640ZELT11  
MAX8640ZELT12  
MAX8640ZELT13  
MAX8640ZELT15  
MAX8640ZELT18  
0.8  
1.1  
1.2  
1.3  
1.5  
1.8  
0.8  
1.1  
1.2  
1.3  
1.5  
1.8  
2.4  
3.4  
3.6  
3.7  
3.9  
4.0  
2.4  
3.4  
3.6  
3.7  
3.9  
4.0  
1
1
1
1
1
1
1
1
1
1
1
1
ACL  
ACM  
ACN  
ACO  
ACP  
ACU  
NK  
NL  
NM  
NN  
NO  
NP  
_______________________________________________________________________________________  
7
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
typically perform well. Due to the MAX8640Y/  
Ordering Information (continued)  
MAX8640Z soft-start, the input capacitance can be very  
low. For optimum noise immunity and low input ripple,  
choose a capacitor value in µF that is equal to or larger  
than the inductor’s value in µH.  
PꢁN-  
PACKAGE  
PKG  
CODE  
TOP  
MARK  
PART*  
MAX8640YELT08+T  
MAX8640YELT11+T  
MAX8640YELT12+T  
MAX8640YELT13+T  
MAX8640YELT15+T  
MAX8640YELT16+T  
MAX8640YELT18+T  
MAX8640YELT19+T  
MAX8640YELT25+T  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
NB  
NC  
PCB Layout and Routing  
High switching frequencies and large peak currents  
make PCB layout a very important part of design. Good  
design minimizes excessive EMI on the feedback paths  
and voltage gradients in the ground plane, both of  
which can result in instability or regulation errors.  
Connect the inductor, input capacitor, and output  
capacitor as close together as possible, and keep their  
traces short, direct, and wide. Connect the two GND  
pins under the IC and directly to the grounds of the  
input and output capacitors. Keep noisy traces, such  
as the LX node, as short as possible. Refer to the  
MAX8640Z evaluation kit for an example PCB layout  
and routing scheme.  
ND  
NE  
NF  
NG  
NH  
NI  
NJ  
ACL  
ACM  
ACN  
ACO  
ACP  
ACU  
NK  
MAX8640ZEXT08+T  
MAX8640ZEXT11+T  
MAX8640ZEXT12+T  
MAX8640ZEXT13+T  
MAX8640ZEXT15+T  
MAX8640ZEXT18+T  
MAX8640ZELT08+T  
MAX8640ZELT11+T  
MAX8640ZELT12+T  
MAX8640ZELT13+T  
MAX8640ZELT15+T  
MAX8640ZELT18+T  
6 SC70-6  
6 SC70-6  
6 SC70-6  
6 SC70-6  
6 SC70-6  
6 SC70-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
6 µDFN-6  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
X6S-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
L611-1  
NL  
Chip Information  
NM  
NN  
PROCESS: BiCMOS  
NO  
NP  
*Contact factory for availability of each version.  
+Denotes a lead-free package.  
T = Tape and reel.  
Note: All devices are specified over the -40°C to +85°C  
operating temperature range.  
8
_______________________________________________________________________________________  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Package Information  
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,  
go to www.maxim-ic.com/packages.)  
PACKAGE OUTLINE, 6L SC70  
1
21-0077  
F
1
_______________________________________________________________________________________  
9
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Package Information (continued)  
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,  
go to www.maxim-ic.com/packages.)  
TOPMARK  
2
3
e
b
5
A
5
4
4
6
PIN 1  
0.075x45  
L
E
AA  
3
2
1
1
A2  
PIN 1  
MARK  
A
A
L2  
L1  
D
A1  
SIDE VIEW  
TOP VIEW  
BOTTOM VIEW  
COMMON DIMENSIONS  
b
MIN.  
0.65  
--  
0.00  
1.45  
0.95  
0.30  
0.00  
0.05  
0.17  
NOM.  
0.72  
0.20  
--  
1.50  
1.00  
0.35  
--  
MAX.  
0.80  
--  
0.05  
1.55  
1.05  
0.40  
0.08  
0.10  
0.23  
A
A1  
A2  
D
E
L
L1  
L2  
b
SECTION A-A  
--  
0.20  
0.50 BSC.  
e
Pkg.  
Code  
L611-1, L611-2  
TITLE:  
PACKAGE OUTLINE, 6L uDFN, 1.5x1.0x0.8mm  
APPROVAL  
DOCUMENT CONTROL NO.  
REV.  
1
-DRAWING NOT TO SCALE-  
21-0147  
E
2
10 ______________________________________________________________________________________  
Tiny 500mA, 4MHz/2MHz Synchronous  
Step-Down DC-DC Converters  
Package Information (continued)  
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,  
go to www.maxim-ic.com/packages.)  
TABLE 1  
Translation Table for Calendar Year Code  
Calendar Year 2005 2006 2007 2008  
2009  
2010  
2011  
2012  
2013  
2014  
Legend:  
Marked with bar  
Blank space - no bar required  
TABLE 2  
Translation Table for Payweek Binary Coding  
Payweek 06-11 12-17 18-23 24-29 30-35  
36-41 42-47  
48-51 52-05  
Legend:  
Marked with bar  
Blank space - no bar required  
TITLE:  
PACKAGE OUTLINE, 6L uDFN, 1.5x1.0x0.8mm  
APPROVAL  
DOCUMENT CONTROL NO.  
REV.  
2
-DRAWING NOT TO SCALE-  
21-0147  
E
2
Revision History  
Pages changed at Rev 1: All  
Pages changed at Rev 2: 1, 7, 8–11  
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 ____________________ 11  
© 2007 Maxim Integrated Products  
is a registered trademark of Maxim Integrated Products, Inc.  

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