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ADP2108AUJZ-3.3-R7

更新时间：2025-07-12 12:39:59
品牌：ADI
描述：Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter

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ADP2108AUJZ-3.3-R7 概述

Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter 小巧的600毫安， 3 MHz的降压型DC - DC转换器 稳压芯片

ADP2108AUJZ-3.3-R7 数据手册

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Compact, 600 mA, 3 MHz,  
Step-Down DC-to-DC Converter  
Data Sheet  
ADP2108  
FEATURES  
GENERAL DESCRIPTION  
Peak efficiency: 95%  
The ADP2108 is a high efficiency, low quiescent current step-  
down dc-to-dc converter manufactured in two different  
packages. The total solution requires only three tiny external  
components. It uses a proprietary, high speed current mode,  
constant frequency PWM control scheme for excellent stability  
and transient response. To ensure the longest battery life in  
portable applications, the ADP2108 has a power save mode that  
reduces the switching frequency under light load conditions.  
3 MHz fixed frequency operation  
Typical quiescent current: 18 μA  
Maximum load current: 600 mA  
Input voltage: 2.3 V to 5.5 V  
Uses tiny multilayer inductors and capacitors  
Current mode architecture for fast load and line  
transient response  
100% duty cycle low dropout mode  
Internal synchronous rectifier  
Internal compensation  
The ADP2108 runs on input voltages of 2.3 V to 5.5 V, which  
allows for single lithium or lithium polymer cell, multiple alkaline  
or NiMH cell, PCMCIA, USB, and other standard power sources.  
The maximum load current of 600 mA is achievable across the  
input voltage range.  
Internal soft start  
Current overload protection  
Thermal shutdown protection  
Shutdown supply current: 0.2 μA  
Available in  
5-ball WLCSP  
5-lead TSOT  
The ADP2108 is available in fixed output voltages of 3.3 V, 3.0 V,  
2.5 V, 2.3 V, 1.82 V, 1.8 V, 1. 5 V, 1.3 V, 1.2 V, 1.1 V, and 1.0 V. All  
versions include an internal power switch and synchronous rect-  
ifier for minimal external part count and high efficiency. The  
ADP2108 has an internal soft start and is internally compensated.  
During logic controlled shutdown, the input is disconnected  
from the output and the ADP2108 draws less than 1 μA from  
the input source.  
Supported by ADIsimPower™ design tool  
APPLICATIONS  
PDAs and palmtop computers  
Wireless handsets  
Digital audio, portable media players  
Digital cameras, GPS navigation units  
Other key features include undervoltage lockout to prevent deep  
battery discharge and soft start to prevent input current over-  
shoot at startup. The ADP2108 is available in 5-ball WLCSP and  
5-lead TSOT packages. The ADP2109 provides the same features  
and operations as the ADP2108 and has the additional function  
of a discharge switch in the WLCSP package.  
TYPICAL APPLICATIONS CIRCUIT  
ADP2108  
1µH  
2.3V TO 5.5V  
4.7µF  
1.0V TO 3.3V  
10µF  
SW  
VIN  
ON  
OFF  
EN  
FB  
GND  
Figure 1.  
Rev. G  
Information furnished by Analog Devices is believed to be accurate and reliable. However, no  
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other  
rightsof third parties that may result fromits use. Specifications subject to change without notice. No  
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.  
Trademarks andregisteredtrademarks are the property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700 www.analog.com  
Fax: 781.461.3113 ©2008–2012 Analog Devices, Inc. All rights reserved.  
 
 
 
 
 
ADP2108  
Data Sheet  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Enable/Shutdown ....................................................................... 11  
Short-Circuit Protection............................................................ 12  
Undervoltage Lockout ............................................................... 12  
Thermal Protection.................................................................... 12  
Soft Start ...................................................................................... 12  
Current Limit.............................................................................. 12  
100% Duty Operation................................................................ 12  
Applications Information .............................................................. 13  
ADIsimPower Design Tool ....................................................... 13  
External Component Selection ................................................ 13  
Thermal Considerations............................................................ 14  
PCB Layout Guidelines.............................................................. 14  
Evaluation Board ............................................................................ 15  
Outline Dimensions....................................................................... 16  
Ordering Guide .......................................................................... 17  
Applications....................................................................................... 1  
General Description ......................................................................... 1  
Typical Applications Circuit............................................................ 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Absolute Maximum Ratings............................................................ 4  
Thermal Resistance ...................................................................... 4  
ESD Caution.................................................................................. 4  
Pin Configuration and Function Descriptions............................. 5  
Typical Performance Characteristics ............................................. 6  
Theory of Operation ...................................................................... 11  
Control Scheme .......................................................................... 11  
PWM Mode................................................................................. 11  
Power Save Mode........................................................................ 11  
REVISION HISTORY  
6/12—Rev. F to Rev. G  
Change to Features Section ............................................................. 1  
Added ADIsimPower Design Tool Section................................. 13  
Updated Outline Dimensions....................................................... 16  
1/12—Rev. E to Rev. F  
Change to Table 3...................................................................................4  
Changes to Output Capacitor Section ......................................... 13  
10/10—Rev. D to Rev. E  
Changed −40°C to +85°C to −40°C to +125°C Throughout .........3  
Changes to Ordering Guide .......................................................... 17  
1/10—Rev. C to Rev. D  
Changes to Ordering Guide .......................................................... 17  
4/09—Rev. B to Rev. C  
Changes to General Description Section ...................................... 1  
2/09—Rev. A to Rev. B  
Added 5-Lead TSOT Package...........................................Universal  
Changes to Absolute Maximum Ratings Section......................... 4  
Updated Outline Dimensions....................................................... 16  
Changes to Ordering Guide .......................................................... 17  
11/08—Rev. 0 to Rev. A  
Changes to Figure 4.......................................................................... 6  
Updated Outline Dimensions....................................................... 16  
9/08—Revision 0: Initial Version  
Rev. G | Page 2 of 20  
 
Data Sheet  
ADP2108  
SPECIFICATIONS  
VIN = 3.6 V, V OUT = 1.8 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless  
otherwise noted.1  
Table 1.  
Parameter  
Test Conditions/Comments  
Min  
2.3  
Typ  
Max  
Unit  
INPUT CHARACTERISTICS  
Input Voltage Range  
Undervoltage Lockout Threshold  
5.5  
V
V
V
VIN rising  
VIN falling  
2.3  
2.05  
2.15  
2.25  
OUTPUT CHARACTERISTICS  
Output Voltage Accuracy  
PWM mode  
−2  
+2  
%
VIN = 2.3 V to 5.5 V, PWM mode  
−2.5  
+2.5  
%
POWER SAVE MODE TO PWM CURRENT THRESHOLD  
PWM TO POWER SAVE MODE CURRENT THRESHOLD  
INPUT CURRENT CHARACTERISTICS  
DC Operating Current  
85  
80  
mA  
mA  
ILOAD = 0 mA, device not switching  
EN = 0 V, TA = TJ = −40°C to +125°C  
18  
30  
µA  
µA  
Shutdown Current  
0.2  
1.0  
SW CHARACTERISTICS  
SW On Resistance (WLCSP)  
PFET  
320  
300  
380  
260  
1300  
mΩ  
mΩ  
mΩ  
mΩ  
mA  
NFET  
SW On Resistance (TSOT)  
PFET  
NFET  
Current Limit  
PFET switch peak current limit  
1100  
1.2  
1500  
ENABLE CHARACTERISTICS  
EN Input High Threshold  
EN Input Low Threshold  
EN Input Leakage Current  
OSCILLATOR FREQUENCY  
START-UP TIME  
V
0.4  
+1  
V
EN = 0 V, 3.6 V  
ILOAD = 200 mA  
−1  
0
µA  
MHz  
µs  
2.5  
3.0  
3.5  
550  
THERMAL CHARACTERISTICS  
Thermal Shutdown Threshold  
Thermal Shutdown Hysteresis  
150  
20  
°C  
°C  
1 All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).  
Rev. G | Page 3 of 20  
 
 
ADP2108  
Data Sheet  
ABSOLUTE MAXIMUM RATINGS  
Table 2.  
Parameter  
VIN, EN  
FB, SW to GND  
Operating Ambient Temperature Range  
Operating Junction Temperature Range  
Storage Temperature Range  
Lead Temperature Range  
Soldering (10 sec)  
In applications with moderate power dissipation and low PCB  
thermal resistance, the maximum ambient temperature can  
exceed the maximum limit as long as the junction temperature  
is within specification limits. The junction temperature (TJ)  
of the device is dependent on the ambient temperature (TA),  
the power dissipation (PD) of the device, and the junction-to-  
ambient thermal resistance of the package (θJA). Maximum  
junction temperature (TJ) is calculated from the ambient  
temperature (TA) and power dissipation (PD) using the formula  
Rating  
−0.4 V to +6.5 V  
−1.0 V to (VIN + 0.2 V)  
−40°C to +125°C  
−40°C to +125°C  
−65°C to +150°C  
−65°C to +150°C  
300°C  
Vapor Phase (60 sec)  
Infrared (15 sec)  
215°C  
TJ = TA + (PD × θJA).  
220°C  
THERMAL RESISTANCE  
ESD Human Body Model  
ESD Charged Device Model  
ESD Machine Model  
1500 V  
θJA is specified for a device mounted on a JEDEC 2S2P PCB.  
500 V  
100 V  
Table 3. Thermal Resistance  
Package Type  
5-Ball WLCSP  
5-Lead TSOT  
θJA  
Unit  
°C/W  
°C/W  
Stresses above those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. This is a stress  
rating only; functional operation of the device at these or any  
other conditions above those indicated in the operational  
section of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
105  
170  
ESD CAUTION  
Absolute maximum ratings apply individually only, not in  
combination. Unless otherwise specified, all other voltages  
are referenced to GND.  
The ADP2108 can be damaged when the junction temperature  
limits are exceeded. Monitoring ambient temperature does not  
guarantee that TJ is within the specified temperature limits.  
In applications with high power dissipation and poor thermal  
resistance, the maximum ambient temperature may have to  
be derated.  
Rev. G | Page 4 of 20  
 
 
 
Data Sheet  
ADP2108  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
BALL A1  
INDICATOR  
1
2
VIN GND  
A
B
C
SW  
EN  
FB  
TOP VIEW  
(BALL SIDE DOWN)  
Not to Scale  
Figure 2. WLCSP Pin Configuration  
Table 4. WLCSP Pin Function Descriptions  
Pin No. Mnemonic Description  
A1  
VIN  
Power Source Input. VIN is the source of the PFET high-side switch. Bypass VIN to GND with a 2.2 μF or greater  
capacitor as close to the ADP2108 as possible.  
A2  
B
C1  
C2  
GND  
SW  
EN  
Ground. Connect all the input and output capacitors to GND.  
Switch Node Output. SW is the drain of the PFET switch and NFET synchronous rectifier.  
Enable Input. Drive EN high to turn on the ADP2108. Drive EN low to turn it off and reduce the input current to 0.2 μA.  
Feedback Input of the Error Amplifier. Connect FB to the output of the switching regulator.  
FB  
5
1
2
3
SW  
VIN  
GND  
EN  
ADP2108  
TOP VIEW  
(Not to Scale)  
4
FB  
Figure 3. TSOT Pin Configuration  
Table 5. TSOT Pin Function Descriptions  
Pin No. Mnemonic Description  
1
VIN  
Power Source Input. VIN is the source of the PFET high-side switch. Bypass VIN to GND with a 2.2 ꢀf or greater  
capacitor as close to the ADP2108 as possible.  
2
3
4
5
GND  
EN  
FB  
Ground. Connect all the input and output capacitors to GND.  
Enable Input. Drive EN high to turn on the ADP2108. Drive EN low to turn it off and reduce the input current to 0.1 ꢀA.  
Feedback Input of the Error Amplifier. Connect FB to the output of the switching regulator.  
Switch Node Output. SW is the drain of the PFET switch and NFET synchronous rectifier.  
SW  
Rev. G | Page 5 of 20  
 
ADP2108  
Data Sheet  
TYPICAL PERFORMANCE CHARACTERISTICS  
VIN = 3.6 V, TA = 25°C, VEN = VIN, unless otherwise noted.  
24  
1400  
1300  
1200  
1100  
1000  
900  
+85°C  
22  
20  
+25°C  
18  
–40°C  
16  
800  
14  
700  
12  
2.5  
600  
2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
Figure 4. Quiescent Supply Current vs. Input Voltage  
Figure 7. PMOS Current Limit vs. Input Voltage  
0.15  
0.14  
0.13  
0.12  
0.11  
0.10  
0.09  
0.08  
0.07  
0.06  
0.05  
0.04  
3500  
3400  
3300  
3200  
3100  
3000  
2900  
2800  
2700  
2600  
2500  
–40°C  
+25°C  
+85°C  
–40°C  
PWM TO PSM  
PSM TO PWM  
+85°C  
2.3  
2.8  
3.3  
3.8  
4.3  
4.8  
5.3  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
Figure 5. Switching Frequency vs. Input Voltage  
Figure 8. Mode Transition Across Temperature  
0.15  
0.14  
0.13  
0.12  
0.11  
0.10  
0.09  
0.08  
0.07  
0.06  
1.840  
1.835  
1.830  
1.825  
1.820  
1.815  
1.810  
1.805  
1.800  
1.795  
I
= 10mA  
OUT  
I
= 150mA  
= 500mA  
OUT  
I
OUT  
PSM TO PWM  
PWM TO PSM  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
–45  
–25  
–5  
15  
35  
55  
75  
INPUT VOLTAGE (V)  
TEMPERATURE (°C)  
Figure 6. Output Voltage vs. Temperature  
Figure 9. Mode Transition  
Rev. G | Page 6 of 20  
 
Data Sheet  
ADP2108  
1.825  
1.815  
1.805  
1.795  
1.785  
1.775  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
V
V
V
V
= 2.7V  
= 3.6V  
= 4.5V  
= 5.5V  
V
V
V
V
= 2.7V  
= 3.6V  
= 4.5V  
= 5.5V  
IN  
IN  
IN  
IN  
IN  
IN  
IN  
IN  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.001  
0.01  
0.1  
1
OUTPUT CURRENT (A)  
OUTPUT CURRENT (A)  
Figure 10. Load Regulation, VOUT = 1.8 V  
Figure 13. Efficiency, VOUT = 1.8 V  
1.025  
1.020  
1.015  
1.010  
1.005  
1.000  
0.995  
0.990  
0.985  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
V
V
V
V
= 2.7V  
= 3.6V  
= 4.5V  
= 5.5V  
IN  
IN  
IN  
IN  
V
V
V
V
= 2.7V  
= 3.6V  
= 4.5V  
= 5.5V  
IN  
IN  
IN  
IN  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.001  
0.01  
0.1  
1
OUTPUT CURRENT (A)  
OUTPUT CURRENT (A)  
Figure 11. Load Regulation, VOUT = 1.0 V  
Figure 14. Efficiency, VOUT = 1.0 V  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
3.3775  
3.3575  
3.3375  
3.3175  
3.2975  
3.2775  
3.2575  
3.2375  
3.2175  
V
V
V
= 3.6V  
= 4.5V  
= 5.5V  
IN  
IN  
IN  
V
V
V
= 3.6V  
= 4.5V  
= 5.5V  
IN  
IN  
IN  
0
0.1  
0.2  
0.3  
0.4  
0.5  
0.6  
0.001  
0.01  
0.1  
1
OUTPUT CURRENT (A)  
OUTPUT CURRENT (A)  
Figure 12. Load Regulation, VOUT = 3.3 V  
Figure 15. Efficiency, VOUT = 3.3 V  
Rev. G | Page 7 of 20  
ADP2108  
Data Sheet  
V
IN  
V
3
IN  
3
SW  
SW  
4
1
4
1
V
OUT  
V
OUT  
CH1 50mV  
CH3 1V  
M 40µs  
10.80%  
A CH3  
4.4V  
CH1 50mV  
CH3 1V  
M 40µs  
10.80%  
A CH3  
3.26V  
CH4 2V  
CH4 2V  
T
T
Figure 16. Line Transient, VOUT = 1.8 V, Power Save Mode, 20 mA  
Figure 19. Line Transient, VOUT = 3.3 V, PWM, 200 mA  
SW  
V
IN  
4
1
SW  
V
OUT  
3
4
V
OUT  
I
OUT  
2
1
CH1 20mV  
CH3 1V  
M 40µs  
10.80%  
A CH3  
3.26V  
CH1 50mV CH2 200mA Ω  
M 40µs  
19.80%  
A CH2  
36mA  
CH4 2V  
CH4 2V  
T
T
Figure 17. Line Transient, VOUT = 1.8 V, PWM, 200 mA  
Figure 20. Load Transient, VOUT = 1.8 V, 300 mA to 600 mA  
V
IN  
4
1
SW  
SW  
3
4
V
OUT  
I
OUT  
V
OUT  
2
1
CH1 50mV  
CH3 1V  
M 40µs  
10.80%  
A CH3  
3.26V  
CH1 50mV CH2 250mA  
CH4 2V  
M 40µs  
25.4%  
A CH2  
5mA  
CH4 2V  
T
T
Figure 18. Line Transient, VOUT = 1.0 V, PWM, 200 mA  
Figure 21. Load Transient, VOUT = 1.8 V, 50 mA to 300 mA  
Rev. G | Page 8 of 20  
Data Sheet  
ADP2108  
SW  
SW  
4
4
1
I
V
OUT  
I
L
2
V
OUT  
OUT  
1
3
EN  
2
CH1 50mV CH2 50mA Ω  
M 40µs  
25.4%  
A CH2  
12mA  
CH1 500mV CH2 500mA  
CH3 5V CH4 5V  
M 40µs  
19.80%  
A CH3  
2.1V  
CH4 2V  
T
T
Figure 22. Load Transient, VOUT = 1.8 V, 5 mA to 50 mA  
Figure 25. Start-Up, VOUT = 1.0 V, 600 mA  
SW  
SW  
4
4
2
I
I
L
L
2
V
V
OUT  
OUT  
EN  
EN  
1
3
1
3
CH1 1V  
CH3 5V  
CH2 250mA  
CH4 5V  
M 40µs  
10.80%  
A CH3  
2V  
CH2 250mA  
CH4 5V  
CH1 2V  
CH3 5V  
M 40µs  
10.80%  
A CH3  
2V  
T
T
Figure 23. Start-Up, VOUT = 1.8 V, 400 mA  
Figure 26. Start-Up, VOUT = 3.3 V, 150 mA  
SW  
4
SW  
4
I
L
2
I
L
2
1
V
OUT  
EN  
1
3
V
OUT  
CH1 1V  
CH3 5V  
CH2 250mA  
CH4 5V  
M 40µs  
10.80%  
A CH3  
2V  
CH1 50mV CH2 500mA  
CH4 2V  
M 2µs  
A CH4  
2.64mA  
T
T
20%  
Figure 27. Typical Power Save Mode Waveform, 50 mA  
Figure 24. Start-Up, VOUT = 1.8 V, 5 mA  
Rev. G | Page 9 of 20  
ADP2108  
Data Sheet  
SW  
4
I
L
2
1
V
OUT  
CH1 20mV CH2 200mA  
CH4 2V  
M 200ns  
A CH4  
2.64V  
T
20%  
Figure 28. Typical PWM Waveform, 200 mA  
Rev. G | Page 10 of 20  
Data Sheet  
ADP2108  
THEORY OF OPERATION  
PWM  
COMP  
GM ERROR  
AMP  
VIN  
SOFT START  
I
LIMIT  
FB  
PSM  
COMP  
PWM/  
PSM  
CONTROL  
LOW  
CURRENT  
SW  
DRIVER  
AND  
OSCILLATOR  
ANTISHOOT-  
THROUGH  
UNDERVOLTAGE  
LOCKOUT  
GND  
THERMAL  
SHUTDOWN  
ADP2108  
EN  
Figure 29. Functional Block Diagram  
The ADP2108 is a step-down dc-to-dc converter that uses a  
fixed frequency and high speed current mode architecture. The  
high switching frequency allows for a small step-down, dc-to-dc  
converter solution.  
POWER SAVE MODE  
The ADP2108 smoothly transitions to the power save mode of  
operation when the load current decreases below the power  
save mode current threshold. When the ADP2108 enters power  
save mode, an offset is induced in the PWM regulation level,  
which makes the output voltage rise. When the output voltage  
reaches a level approximately 1.5% above the PWM regulation  
level, PWM operation is turned off. At this point, both power  
switches are off, and the ADP2108 enters an idle mode. COUT  
discharges until VOUT falls to the PWM regulation voltage, at  
which point the device drives the inductor to make VOUT rise  
again to the upper threshold. This process is repeated while the  
load current is below the power save mode current threshold.  
The ADP2108 operates with an input voltage of 2.3 V to 5.5 V  
and regulates an output voltage down to 1.0 V.  
CONTROL SCHEME  
The ADP2108 operates with a fixed frequency, current mode  
PWM control architecture at medium to high loads for high  
efficiency, but shifts to a power save mode control scheme at  
light loads to lower the regulation power losses. When operating  
in fixed frequency PWM mode, the duty cycle of the integrated  
switches is adjusted and regulates the output voltage. When  
operating in power save mode at light loads, the output voltage  
is controlled in a hysteretic manner, with higher VOUT ripple.  
During part of this time, the converter is able to stop switching  
and enters an idle mode, which improves conversion efficiency.  
Power Save Mode Current Threshold  
The power save mode current threshold is set to 80 mA. The  
ADP2108 employs a scheme that enables this current to remain  
accurately controlled, independent of VIN and VOUT levels. This  
scheme also ensures that there is very little hysteresis between  
the power save mode current threshold for entry to and exit from  
the power save mode. The power save mode current threshold  
is optimized for excellent efficiency over all load currents.  
PWM MODE  
In PWM mode, the ADP2108 operates at a fixed frequency of  
3 MHz, set by an internal oscillator. At the start of each oscillator  
cycle, the PFET switch is turned on, sending a positive voltage  
across the inductor. Current in the inductor increases until the  
current sense signal crosses the peak inductor current threshold  
that turns off the PFET switch and turns on the NFET synchronous  
rectifier. This sends a negative voltage across the inductor, causing  
the inductor current to decrease. The synchronous rectifier stays  
on for the rest of the cycle. The ADP2108 regulates the output  
voltage by adjusting the peak inductor current threshold.  
ENABLE/SHUTDOWN  
The ADP2108 starts operation with soft start when the EN pin  
is toggled from logic low to logic high. Pulling the EN pin low  
forces the device into shutdown mode, reducing the shutdown  
current below 1 μA.  
Rev. G | Page 11 of 20  
 
 
 
 
 
ADP2108  
Data Sheet  
After the EN pin is driven high, internal circuits start to power up.  
The time required to settle after the EN pin is driven high is called  
the power-up time. After the internal circuits are powered up, the  
soft start ramp is initiated and the output capacitor is charged  
linearly until the output voltage is in regulation. The time required  
for the output voltage to ramp is called the soft start time.  
SHORT-CIRCUIT PROTECTION  
The ADP2108 includes frequency foldback to prevent output  
current runaway on a hard short. When the voltage at the  
feedback pin falls below half the target output voltage, indicat-  
ing the possibility of a hard short at the output, the switching  
frequency is reduced to half the internal oscillator frequency.  
The reduction in the switching frequency allows more time for  
the inductor to discharge, preventing a runaway of output current.  
Start-up time in the ADP2108 is the measure of when the  
output is in regulation after the EN pin is driven high. Start-up  
time consists of the power-up time and the soft start time.  
UNDERVOLTAGE LOCKOUT  
CURRENT LIMIT  
To protect against battery discharge, undervoltage lockout  
(UVLO) circuitry is integrated on the ADP2108. If the input  
voltage drops below the 2.15 V UVLO threshold, the ADP2108  
shuts down, and both the power switch and the synchronous  
rectifier turn off. When the voltage rises above the UVLO thresh-  
old, the soft start period is initiated, and the part is enabled.  
The ADP2108 has protection circuitry to limit the amount of  
positive current flowing through the PFET switch and the  
synchronous rectifier. The positive current limit on the power  
switch limits the amount of current that can flow from the input  
to the output. The negative current limit prevents the inductor  
current from reversing direction and flowing out of the load.  
THERMAL PROTECTION  
100% DUTY OPERATION  
In the event that the ADP2108 junction temperature rises above  
150°C, the thermal shutdown circuit turns off the converter.  
Extreme junction temperatures can be the result of high current  
operation, poor circuit board design, or high ambient temperature.  
A 20°C hysteresis is included so that when thermal shutdown  
occurs, the ADP2108 does not return to operation until the  
on-chip temperature drops below 130°C. When coming out  
of thermal shutdown, soft start is initiated.  
With a drop in VIN or with an increase in ILOAD, the ADP2108  
reaches a limit where, even with the PFET switch on 100% of  
the time, VOUT drops below the desired output voltage. At this  
limit, the ADP2108 smoothly transitions to a mode where the  
PFET switch stays on 100% of the time. When the input conditions  
change again and the required duty cycle falls, the ADP2108  
immediately restarts PWM regulation without allowing over-  
shoot on VOUT  
.
SOFT START  
The ADP2108 has an internal soft start function that ramps the  
output voltage in a controlled manner upon startup, thereby  
limiting the inrush current. This prevents possible input voltage  
drops when a battery or a high impedance power source is  
connected to the input of the converter.  
Rev. G | Page 12 of 20  
 
 
 
 
 
 
Data Sheet  
ADP2108  
APPLICATIONS INFORMATION  
ADIsimPower DESIGN TOOL  
Table 6. Suggested 1.0 μH Inductors  
Vendor Model Dimensions  
The ADP2108 is supported by ADIsimPower design tool set.  
ADIsimPower is a collection of tools that produce complete  
power designs optimized for a specific design goal. The tools  
enable the user to generate a full schematic, bill of materials,  
and calculate performance in minutes. ADIsimPower can  
optimize designs for cost, area, efficiency, and parts count  
while taking into consideration the operating conditions and  
limitations of the IC and all real external components. For  
more information about ADIsimPower design tools, refer to  
www.analog.com/ADIsimPower. The tool set is available from  
this website, and users can also request an unpopulated board  
through the tool.  
ISAT (mA) DCR (mΩ)  
Murata  
Murata  
Murata  
LQM21PN1R0M 2.0 × 1.25 × 0.5 800  
LQM31PN1R0M 3.2 × 1.6 × 0.85 1200  
LQM2HPN1R0M 2.5 × 2.0 × 1.1  
190  
120  
90  
1500  
1700  
1800  
1500  
Coilcraft LPS3010-102  
3.0 × 3.0 × 0.9  
2.5 × 2.0 × 1.2  
2.5 × 1.5 × 1.2  
85  
Toko  
TDK  
MDT2520-CN  
CPL2512T  
100  
100  
Output Capacitor  
Higher output capacitor values reduce the output voltage ripple  
and improve load transient response. When choosing this value,  
it is also important to account for the loss of capacitance due to  
output voltage dc bias.  
EXTERNAL COMPONENT SELECTION  
Ceramic capacitors are manufactured with a variety of dielectrics,  
each with different behavior over temperature and applied voltage.  
Capacitors must have a dielectric adequate to ensure the minimum  
capacitance over the necessary temperature range and dc bias  
conditions. X5R or X7R dielectrics with a voltage rating of 6.3 V  
or 10 V are recommended for best performance. Y5V and Z5U  
dielectrics are not recommended for use with any dc-to-dc  
converter because of their poor temperature and dc bias  
characteristics.  
Trade-offs between performance parameters such as efficiency  
and transient response can be made by varying the choice of  
external components in the applications circuit, as shown in  
Figure 1.  
Inductor  
The high switching frequency of the ADP2108 allows for the  
selection of small chip inductors. For best performance, use  
inductor values between 0.7 μH and 3 μH. Recommended  
inductors are shown in Table 6.  
The worst-case capacitance accounting for capacitor variation  
over temperature, component tolerance, and voltage is calcu-  
lated using the following equation:  
The peak-to-peak inductor current ripple is calculated using  
the following equation:  
C
EFF = COUT × (1 − TEMPCO) × (1 − TOL)  
where:  
EFF is the effective capacitance at the operating voltage.  
VOUT ×(VIN −VOUT  
)
IRIPPLE  
=
V
IN × fSW ×L  
C
where:  
SW is the switching frequency.  
L is the inductor value.  
TEMPCO is the worst-case capacitor temperature coefficient.  
TOL is the worst-case component tolerance.  
f
In this example, the worst-case temperature coefficient (TEMPCO)  
over −40°C to +125°C is assumed to be 15% for an X5R dielectric.  
The tolerance of the capacitor (TOL) is assumed to be 10%, and  
The minimum dc current rating of the inductor must be greater  
than the inductor peak current. The inductor peak current is  
calculated using the following equation:  
C
OUT is 9.2 μF at 1.8 V, as shown in Figure 30.  
Substituting these values in the equation yields  
EFF = 9.2 μF × (1 − 0.15) × (1 − 0.1) = 7.0 μF  
IRIPPLE  
2
IPEAK = ILOAD(MAX)  
+
C
Inductor conduction losses are caused by the flow of current  
through the inductor, which has an associated internal DCR.  
Larger sized inductors have smaller DCR, which may decrease  
inductor conduction losses. Inductor core losses are related to  
the magnetic permeability of the core material. Because the  
ADP2108 is a high switching frequency dc-to-dc converter,  
shielded ferrite core material is recommended for its low core  
losses and low EMI.  
To guarantee the performance of the ADP2108, it is imperative  
that the effects of dc bias, temperature, and tolerances on the  
behavior of the capacitors be evaluated for each application.  
Rev. G | Page 13 of 20  
 
 
 
 
ADP2108  
Data Sheet  
12  
10  
8
THERMAL CONSIDERATIONS  
Because of the high efficiency of the ADP2108, only a small  
amount of power is dissipated inside the ADP2108 package,  
which reduces thermal constraints.  
However, in applications with maximum loads at high ambient  
temperature, low supply voltage, and high duty cycle, the heat  
dissipated in the package is great enough that it may cause the  
junction temperature of the die to exceed the maximum  
junction temperature of 125°C. If the junction temperature  
exceeds 150°C, the converter goes into thermal shutdown. It  
recovers when the junction temperature falls below 130°C.  
6
4
2
0
0
1
2
3
4
5
6
The junction temperature of the die is the sum of the ambient  
temperature of the environment and the temperature rise of the  
package due to power dissipation, as shown in the following  
equation:  
DC BIAS VOLTAGE (V)  
Figure 30. Typical Capacitor Performance  
The peak-to-peak output voltage ripple for the selected output  
capacitor and inductor values is calculated using the following  
equation:  
TJ = TA + TR  
where:  
IRIPPLE  
8× fSW ×COUT  
VIN  
2 ×L×COUT  
TJ is the junction temperature.  
TA is the ambient temperature.  
TR is the rise in temperature of the package due to power  
dissipation.  
VRIPPLE  
=
≈
(
2π× fSW  
)
Capacitors with lower equivalent series resistance (ESR) are  
preferred to guarantee low output voltage ripple, as shown in  
the following equation:  
The rise in temperature of the package is directly proportional  
to the power dissipation in the package. The proportionality  
constant for this relationship is the thermal resistance from the  
junction of the die to the ambient temperature, as shown in the  
following equation:  
VRIPPLE  
IRIPPLE  
ESRCOUT  
≤
The effective capacitance needed for stability, which includes  
temperature and dc bias effects, is 7 µF.  
TR = θJA × PD  
where:  
Table 7. Suggested 10 μF Capacitors  
TR is the rise in temperature of the package.  
Case  
Size  
Voltage  
Rating (V)  
θ
JA is the thermal resistance from the junction of the die to the  
Vendor  
Murata  
Taiyo Yuden  
TDK  
Type  
X5R  
X5R  
X5R  
Model  
ambient temperature of the package.  
PD is the power dissipation in the package.  
GRM188R60J106  
JMK107BJ106  
C1608JB0J106K  
0603  
0603  
0603  
6.3  
6.3  
6.3  
PCB LAYOUT GUIDELINES  
Input Capacitor  
Poor layout can affect ADP2108 performance, causing electro-  
magnetic interference (EMI) and electromagnetic compatibility  
(EMC) problems, ground bounce, and voltage losses. Poor  
layout can also affect regulation and stability. A good layout is  
implemented using the following rules:  
Higher value input capacitors help to reduce the input voltage  
ripple and improve transient response. Maximum input  
capacitor current is calculated using the following equation:  
VOUT (VIN −VOUT  
)
ICIN ≥ ILOAD(MAX)  
•
Place the inductor, input capacitor, and output capacitor  
close to the IC using short tracks. These components carry  
high switching frequencies, and large tracks act as antennas.  
Route the output voltage path away from the inductor and  
SW node to minimize noise and magnetic interference.  
Maximize the size of ground metal on the component side  
to help with thermal dissipation.  
VIN  
To minimize supply noise, place the input capacitor as close to  
the VIN pin of the ADP2108 as possible. As with the output  
capacitor, a low ESR capacitor is recommended. The list of  
recommended capacitors is shown in Table 8.  
•
•
•
Table 8. Suggested 4.7 μF Capacitors  
Use a ground plane with several vias connecting to the com-  
ponent side ground to further reduce noise interference on  
sensitive circuit nodes.  
Case  
Size  
Voltage  
Rating (V)  
Vendor  
Murata  
Taiyo Yuden  
TDK  
Type  
X5R  
X5R  
X5R  
Model  
GRM188R60J475  
JMK107BJ475  
C1608X5R0J475  
0603  
0603  
0603  
6.3  
6.3  
6.3  
Rev. G | Page 14 of 20  
 
 
 
 
Data Sheet  
ADP2108  
EVALUATION BOARD  
ADP2108  
L1  
1µH  
TB1  
TB3  
TB4  
V
V
OUT  
IN  
A1  
A2  
C1  
B
1
2
VIN  
GND  
EN  
SW  
V
V
OUT  
IN  
C
IN  
4.7µF  
C
OUT  
10µF  
TB2  
TB5  
EN  
C2  
FB  
EN  
U1  
GND OUT  
GND IN  
Figure 31. Evaluation Board Schematic  
Figure 34. Recommended TSOT Top Layer  
Figure 32. Recommended WLCSP Top Layer  
Figure 35. Recommended TSOT Bottom Layer  
Figure 33. Recommended WLCSP Bottom Layer  
Rev. G | Page 15 of 20  
 
ADP2108  
Data Sheet  
OUTLINE DIMENSIONS  
1.060  
1.020  
0.980  
2
1
A
B
BALL A1  
IDENTIFIER  
1.490  
1.450  
1.410  
0.866  
REF  
C
0.50  
BSC  
TOP VIEW  
(BALL SIDE DOWN)  
0.50 BSC  
0.355  
0.330  
0.304  
BOTTOM VIEW  
(BALL SIDE UP)  
0.657  
0.602  
0.546  
SIDE VIEW  
COPLANARITY  
0.04  
0.330  
0.310  
0.290  
0.280  
0.250  
0.220  
SEATING  
PLANE  
Figure 36. 5-Ball Wafer Level Chip Scale Package [WLCSP]  
(CB-5-3)  
Dimensions shown in millimeters  
2.90 BSC  
5
1
4
3
2.80 BSC  
1.60 BSC  
2
0.95 BSC  
1.90  
BSC  
*
0.90 MAX  
0.70 MIN  
*
1.00 MAX  
0.20  
0.08  
8°  
4°  
0°  
0.10 MAX  
0.50  
0.30  
0.60  
0.45  
0.30  
SEATING  
PLANE  
*
COMPLIANT TO JEDEC STANDARDS MO-193-AB WITH  
THE EXCEPTION OF PACKAGE HEIGHT AND THICKNESS.  
Figure 37. 5-Lead Thin Small Outline Transistor Package [TSOT]  
(UJ-5)  
Dimensions shown in millimeters  
Rev. G | Page 16 of 20  
 
Data Sheet  
ADP2108  
ORDERING GUIDE  
Output  
Voltage (V)  
Package  
Model1  
Temperature Range  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
−40°C to +125°C  
Package Description  
Option  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
CB-5-3  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
UJ-5  
Branding  
LA6  
LA7  
LA8  
LA9  
LAA  
LAD  
LAE  
ADP2108ACBZ-1.0-R7  
ADP2108ACBZ-1.1-R7  
ADP2108ACBZ-1.2-R7  
ADP2108ACBZ-1.3-R7  
ADP2108ACBZ-1.5-R7  
ADP2108ACBZ-1.8-R7  
ADP2108ACBZ-1.82-R7  
ADP2108ACBZ-2.3-R7  
ADP2108ACBZ-2.5-R7  
ADP2108ACBZ-3.0-R7  
ADP2108ACBZ-3.3-R7  
ADP2108AUJZ-1.0-R7  
ADP2108AUJZ-1.1-R7  
ADP2108AUJZ-1.2-R7  
ADP2108AUJZ-1.3-R7  
ADP2108AUJZ-1.5-R7  
ADP2108AUJZ-1.8-R7  
ADP2108AUJZ-1.82-R7  
ADP2108AUJZ-2.3-R7  
ADP2108AUJZ-2.5-R7  
ADP2108AUJZ-3.0-R7  
ADP2108AUJZ-3.3-R7  
ADP2108-1.0-EVALZ  
ADP2108-1.1-EVALZ  
ADP2108-1.2-EVALZ  
ADP2108-1.3-EVALZ  
ADP2108-1.5-EVALZ  
ADP2108-1.8-EVALZ  
ADP2108-1.82-EVALZ  
ADP2108-2.3-EVALZ  
ADP2108-2.5-EVALZ  
ADP2108-3.0-EVALZ  
ADP2108-3.3-EVALZ  
ADP2108UJZ-REDYKIT  
1.0  
1.1  
1.2  
1.3  
1.5  
1.8  
1.82  
2.3  
2.5  
3.0  
3.3  
1.0  
1.1  
1.2  
1.3  
1.5  
1.8  
1.82  
2.3  
2.5  
3.0  
3.3  
1.0  
1.1  
1.2  
1.3  
1.5  
1.8  
1.82  
2.3  
2.5  
3.0  
3.3  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Ball Wafer Level Chip Scale Package [WLCSP]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
5-Lead Small Outline Package [TSOT]  
Evaluation Board for 1.0 V [WLCSP]  
LAF  
LAG  
LD9  
LAH  
LA6  
LA7  
LA8  
LA9  
LAA  
LAD  
LAE  
LAF  
LAG  
LD9  
LAH  
UJ-5  
UJ-5  
Evaluation Board for 1.1 V [WLCSP]  
Evaluation Board for 1.2 V [WLCSP]  
Evaluation Board for 1.3 V [WLCSP]  
Evaluation Board for 1.5 V [WLCSP]  
Evaluation Board for 1.8 V [WLCSP]  
Evaluation Board for 1.82 V [WLCSP]  
Evaluation Board for 2.3 V [WLCSP]  
Evaluation Board for 2.5 V [WLCSP]  
Evaluation Board for 3.0 V [WLCSP]  
Evaluation Board for 3.3 V [WLCSP]  
Evaluation Board for Fixed Output Voltage,  
1.2 V and 3.3 V [TSOT]  
1 Z = RoHS Compliant Part.  
Rev. G | Page 17 of 20  
 
 
ADP2108  
NOTES  
Data Sheet  
Rev. G | Page 18 of 20  
Data Sheet  
NOTES  
ADP2108  
Rev. G | Page 19 of 20  
ADP2108  
NOTES  
Data Sheet  
©2008–2012 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D07375-0-6/12(G)  
Rev. G | Page 20 of 20  

ADP2108AUJZ-3.3-R7 CAD模型

原理图符号

PCB 封装图

3D模型

ADP2108AUJZ-3.3-R7 替代型号

型号 制造商 描述 替代类型 文档
ADP2108AUJZ-1.82-R7 ADI Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter 完全替代
ADP2108AUJZ-1.2-R7 ADI Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter 类似代替
ADP2108AUJZ-1.8-R7 ADI Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter 类似代替

ADP2108AUJZ-3.3-R7 相关器件

型号 制造商 描述 价格 文档
ADP2108UJZ-REDYKIT ADI Compact, 600 mA, 3 MHz, Step-Down DC-to-DC Converter 获取价格
ADP2109 ADI Compact 600 mA, 3 MHz, Step-Down Converter with Output Discharge 获取价格
ADP2109ACBZ-1.0-R7 ADI 元器件封装:5-WFBGA; 获取价格
ADP2109ACBZ-1.2-R7 ADI 元器件封装:5-WFBGA; 获取价格
ADP2109ACBZ-1.5-R7 ADI 元器件封装:5-WFBGA; 获取价格
ADP2109ACBZ-1.8-R7 ADI 获取价格
ADP2114 ADI Configurable, Dual 2 A/Single 4 A, Synchronous Step-Down DC-to-DC Regulator 获取价格
ADP2114-2PH-EVALZ ADI Configurable, Dual 2 A/Single 4 A, Synchronous Step-Down DC-to-DC Regulator 获取价格
ADP2114-EVALZ ADI Configurable, Dual 2 A/Single 4 A, Synchronous Step-Down DC-to-DC Regulator 获取价格
ADP2114ACPZ-R2 ADI Configurable, Dual 2 A/Single 4 A, Synchronous Step-Down DC-to-DC Regulator 获取价格

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