ADP1754ACPZ-1.1-R7 [ADI]

1.2 A, Low VIN, Low Dropout Linear Regulator; 1.2 A ,低VIN ,低压差线性稳压器
ADP1754ACPZ-1.1-R7
型号: ADP1754ACPZ-1.1-R7
厂家: ADI    ADI
描述:

1.2 A, Low VIN, Low Dropout Linear Regulator
1.2 A ,低VIN ,低压差线性稳压器

线性稳压器IC 调节器 电源电路 输出元件
文件: 总20页 (文件大小:709K)
中文:  中文翻译
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1.2 A, Low VIN, Low Dropout  
Linear Regulator  
Data Sheet  
ADP1754/ADP1755  
FEATURES  
TYPICAL APPLICATION CIRCUITS  
V
IN  
= 1.8V  
V
= 1.5V  
OUT  
Maximum output current: 1.2 A  
Input voltage range: 1.6 V to 3.6 V  
Low shutdown current: <2 µA  
Very low dropout voltage: 105 mV @ 1.2 A load  
Initial accuracy: 1%  
Accuracy over line, load, and temperature: 2%  
7 fixed output voltage options with soft start  
0.75 V to 2.5 V (ADP1754)  
4.7µF  
4.7µF  
14  
VIN VIN VOUT VOUT  
13  
16  
15  
1 VIN  
2 VIN  
3 VIN  
4 EN  
VOUT 12  
ADP1754  
TOP VIEW  
(Not to Scale)  
VOUT 11  
VOUT 10  
SENSE 9  
100kΩ  
PG  
Adjustable output voltage option with soft start  
0.75 V to 3.3V (ADP1755)  
High PSRR  
PG GND SS NC  
7
8
5
6
65 dB @ 1 kHz  
10nF  
65 dB @ 10 kHz  
54 dB @ 100 kHz  
Figure 1. ADP1754 with Fixed Output Voltage, 1.5 V  
23 μV rms at 0.75 V output  
V
= 1.8V  
V
= 0.5V(1 + R1/R2)  
IN  
OUT  
Stable with small 4.7 µF ceramic output capacitor  
Excellent load and line transient response  
Current-limit and thermal overload protection  
Power-good indicator  
Logic-controlled enable  
Reverse current protection  
4.7µF  
4.7µF  
14  
VIN VIN VOUT VOUT  
13  
16  
15  
1 VIN  
2 VIN  
3 VIN  
4 EN  
VOUT 12  
ADP1755  
TOP VIEW  
(Not to Scale)  
VOUT 11  
VOUT 10  
100kΩ  
R1  
APPLICATIONS  
PG  
ADJ  
PG GND SS NC  
9
Server computers  
Memory components  
R2  
7
8
5
6
Telecommunications equipment  
Network equipment  
10nF  
DSP/FPGA/microprocessor supplies  
Instrumentation equipment/data acquisition systems  
Figure 2. ADP1755 with Adjustable Output Voltage, 0.75 V to 3.3 V  
GENERAL DESCRIPTION  
voltages that range from 0.75 V to 3.3 V via an external divider.  
The ADP1754/ADP1755 allow an external soft start capacitor  
to be connected to program the startup. A digital power-good  
output allows power system monitors to check the health of the  
output voltage.  
The ADP1754/ADP1755 are low dropout (LDO) CMOS linear  
regulators that operate from 1.6 V to 3.6 V and provide up to  
1.2 A of output current. These low VIN/VOUT LDOs are ideal for  
regulation of nanometer FPGA geometries operating from 2.5 V  
down to 1.8 V I/O rails, and for powering core voltages down to  
0.75 V. Using an advanced proprietary architecture, the ADP1754/  
ADP1755 provide high power supply rejection ratio (PSRR) and  
low noise, and achieve excellent line and load transient response  
with only a small 4.7 µF ceramic output capacitor.  
The ADP1754/ADP1755 are available in a 16-lead, 4 mm × 4 mm  
LFCSP, making them not only very compact solutions, but also  
providing excellent thermal performance for applications that  
require up to 1.2 A of output current in a small, low profile  
footprint.  
The ADP1754 is available in seven fixed output voltage options.  
The ADP1755 is the adjustable version, which allows output  
Rev. F  
Document Feedback  
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Tel: 781.329.4700 ©2008–2013 Analog Devices, Inc. All rights reserved.  
Technical Support  
www.analog.com  
 
 
 
 
ADP1754/ADP1755  
Data Sheet  
TABLE OF CONTENTS  
Soft Start Function (ADP1754/ADP1755) ............................. 11  
Adjustable Output Voltage (ADP1755)................................... 12  
Enable Feature ............................................................................ 12  
Power-Good Feature.................................................................. 12  
Reverse Current Protection Feature ........................................ 13  
Applications Information .............................................................. 14  
Capacitor Selection .................................................................... 14  
Undervoltage Lockout ............................................................... 15  
Current-Limit and Thermal Overload Protection................. 15  
Thermal Considerations............................................................ 15  
PCB Layout Considerations...................................................... 18  
Outline Dimensions....................................................................... 19  
Ordering Guide .......................................................................... 19  
Features .............................................................................................. 1  
Applications....................................................................................... 1  
Typical Application Circuits............................................................ 1  
General Description ......................................................................... 1  
Revision History ............................................................................... 2  
Specifications..................................................................................... 3  
Input and Output Capacitor, Recommended Specifications.. 4  
Absolute Maximum Ratings............................................................ 5  
Thermal Data ................................................................................ 5  
Thermal Resistance ...................................................................... 5  
ESD Caution.................................................................................. 5  
Pin Configurations and Function Descriptions ........................... 6  
Typical Performance Characteristics ............................................. 7  
Theory of Operation ...................................................................... 11  
REVISION HISTORY  
8/13—Rev. E to Rev. F  
4/09—Rev. 0 to Rev. A  
Changes to Ordering Guide .......................................................... 19  
Changes to Adjustable Output Voltage Accuracy (ADP1755)  
Parameter, Table 1 .............................................................................3  
Changes to Table 3.............................................................................5  
6/13—Rev. D to Rev. E  
Changed Adjustable Output Voltage Option with Soft Start  
(ADP1755) from 0.75 V to 3.0 V to 0.75 V to 3.3 V  
10/08—Revision 0: Initial Version  
(Throughout) .................................................................................... 1  
Updated Outline Dimensions....................................................... 19  
12/12—Rev. C to Rev. D  
Added Junction Temperature of 150°C, Table 3........................... 5  
9/12—Rev. B to Rev. C  
Changes to Absolute Maximum Ratings, Table 3......................... 5  
Changes to Ordering Guide .......................................................... 19  
2/10—Rev. A to Rev. B  
Changes to Table 4............................................................................ 5  
Changes to Ordering Guide .......................................................... 19  
Rev. F | Page 2 of 20  
 
Data Sheet  
ADP1754/ADP1755  
SPECIFICATIONS  
VIN = (VOUT + 0.4 V) or 1.6 V (whichever is greater), IOUT = 10 mA, CIN = COUT = 4.7 µF, TA = 25°C, unless otherwise noted.  
Table 1.  
Parameter  
Symbol  
VIN  
Test Conditions/Comments  
TJ = −40°C to +125°C  
Min  
Typ Max  
Unit  
V
INPUT VOLTAGE RANGE  
OPERATING SUPPLY CURRENT1  
1.6  
3.6  
90  
400  
IGND  
IOUT = 500 μA  
IOUT = 100 mA  
IOUT = 100 mA, TJ = −40°C to +125°C  
IOUT = 1.2 A  
IOUT = 1.2 A, TJ = −40°C to +125°C  
EN = GND, VIN = 1.6 V  
µA  
µA  
µA  
mA  
mA  
µA  
µA  
µA  
800  
1.1  
1.4  
SHUTDOWN CURRENT  
IGND-SD  
2
6
EN = GND, VIN = 1.6 V, TJ = −40°C to +85°C  
EN = GND, VIN = 3.6 V, TJ = −40°C to +85°C  
30  
100  
OUTPUT VOLTAGE ACCURACY  
Fixed Output Voltage Accuracy  
(ADP1754)  
VOUT  
IOUT = 10 mA  
IOUT = 10 mA to 1.2 A  
10 mA < IOUT < 1.2 A, TJ = −40°C to +125°C  
IOUT = 10 mA  
IOUT = 10 mA to 1.2 A  
−1  
−1.5  
−2  
0.495 0.5  
0.495  
+1  
+1.5  
+2  
0.505  
0.505  
0.510  
+0.3  
0.6  
%
%
%
V
Adjustable Output Voltage Accuracy  
(ADP1755)2  
VADJ  
V
10 mA < IOUT < 1.2 A, TJ = −40°C to +125°C  
0.490  
V
LINE REGULATION  
LOAD REGULATION3  
DROPOUT VOLTAGE4  
∆VOUT/∆VIN VIN = (VOUT + 0.4 V) to 3.6 V, TJ = −40°C to +125°C  
∆VOUT/∆IOUT IOUT = 10 mA to 1.2 A, TJ = −40°C to +125°C  
−0.3  
%/V  
%/A  
mV  
mV  
mV  
mV  
µs  
VDROPOUT  
IOUT = 100 mA, VOUT ≥ 1.8 V  
IOUT = 100 mA, VOUT ≥ 1.8 V, TJ = −40°C to +125°C  
IOUT = 1.2 A, VOUT ≥ 1.8 V  
IOUT = 1.2 A, VOUT ≥ 1.8 V, TJ = −40°C to +125°C  
CSS = 0 nF, IOUT = 10 mA  
CSS = 10 nF, IOUT = 10 mA  
10  
16  
105  
200  
START-UP TIME5  
tSTART-UP  
ILIMIT  
200  
5.2  
ms  
A
CURRENT-LIMIT THRESHOLD6  
THERMAL SHUTDOWN  
Thermal Shutdown Threshold  
Thermal Shutdown Hysteresis  
1.5  
1.0  
2
5
TSSD  
TJ rising  
150  
15  
°C  
°C  
TSSD-HYS  
PG OUTPUT LOGIC LEVEL  
PG Output Logic High  
PG Output Logic Low  
PG Output Delay from EN Transition  
Low to High  
PGHIGH  
PGLOW  
1.6 V ≤ VIN ≤ 3.6 V, IOH < 1 µA  
1.6 V ≤ VIN ≤ 3.6 V, IOL < 2 mA  
1.6 V ≤ VIN ≤ 3.6 V, CSS = 10 nF  
V
V
ms  
0.4  
5.5  
PG OUTPUT THRESHOLD  
Output Voltage Falling  
Output Voltage Rising  
EN INPUT  
PGFALL  
PGRISE  
1.6 V ≤ VIN ≤ 3.6 V  
1.6 V ≤ VIN ≤ 3.6 V  
−10  
−6.5  
%
%
EN Input Logic High  
EN Input Logic Low  
VIH  
VIL  
1.6 V ≤ VIN ≤ 3.6 V  
1.6 V ≤ VIN ≤ 3.6 V  
EN = VIN or GND  
1.2  
V
V
µA  
0.4  
1
EN Input Leakage Current  
UNDERVOLTAGE LOCKOUT  
Input Voltage Rising  
Input Voltage Falling  
Hysteresis  
VI-LEAKAGE  
UVLO  
UVLORISE  
UVLOFALL  
UVLOHYS  
ISS  
0.1  
TJ = −40°C to +125°C  
TJ = −40°C to +125°C  
TJ = 25°C  
1.58  
V
V
mV  
µA  
nA  
µA  
1.25  
0.6  
100  
0.9  
10  
SOFT START CURRENT  
ADJ INPUT BIAS CURRENT (ADP1755)  
SENSE INPUT BIAS CURRENT  
1.6 V ≤ VIN ≤ 3.6 V  
1.2  
ADJI-BIAS  
SNSI-BIAS  
1.6 V ≤ VIN ≤ 3.6 V, TJ = −40°C to +125°C  
1.6 V ≤ VIN ≤ 3.6 V  
150  
10  
Rev. F | Page 3 of 20  
 
ADP1754/ADP1755  
Data Sheet  
Parameter  
Symbol  
Test Conditions/Comments  
10 Hz to 100 kHz, VOUT = 0.75 V  
10 Hz to 100 kHz, VOUT = 2.5 V  
VIN = VOUT + 1 V, IOUT = 10 mA  
1 kHz, VOUT = 0.75 V  
1 kHz, VOUT = 2.5 V  
10 kHz, VOUT = 0.75 V  
10 kHz, VOUT = 2.5 V  
100 kHz, VOUT = 0.75 V  
100 kHz, VOUT = 2.5 V  
Min  
Typ Max  
Unit  
OUTPUT NOISE  
OUTNOISE  
23  
65  
µV rms  
µV rms  
POWER SUPPLY REJECTION RATIO  
PSRR  
65  
56  
65  
56  
54  
51  
dB  
dB  
dB  
dB  
dB  
dB  
1 Minimum output load current is 500 μA.  
2 Accuracy when VOUT is connected directly to ADJ. When VOUT voltage is set by external feedback resistors, absolute accuracy in adjust mode depends on the  
tolerances of resistors used.  
3 Based on an end-point calculation using 10 mA and 1.2 A loads. See Figure 6 for typical load regulation performance.  
4 Dropout voltage is defined as the input to output voltage differential when the input voltage is set to the nominal output voltage. This applies only to output voltages  
above 1.6 V.  
5 Start-up time is defined as the time between the rising edge of EN to VOUT being at 95% of its nominal value.  
6 Current-limit threshold is defined as the current at which the output voltage drops to 90% of the specified typical value. For example, the current limit for a 1.0 V  
output voltage is defined as the current that causes the output voltage to drop to 90% of 1.0 V, or 0.9 V.  
INPUT AND OUTPUT CAPACITOR, RECOMMENDED SPECIFICATIONS  
Table 2.  
Parameter  
MINIMUM INPUT AND OUTPUT CAPACITANCE1  
Symbol  
CMIN  
Test Conditions/Comments  
TA = −40°C to +125°C  
Min  
3.3  
Typ  
Max  
Unit  
µF  
CAPACITOR ESR  
RESR  
TA = −40°C to +125°C  
0.001  
0.1  
1 The minimum input and output capacitance should be greater than 3.3 µF over the full range of operating conditions. The full range of operating conditions in the  
application must be considered during device selection to ensure that the minimum capacitance specification is met. X7R and X5R type capacitors are recommended;  
Y5V and Z5U capacitors are not recommended for use with this LDO.  
Rev. F | Page 4 of 20  
 
 
 
Data Sheet  
ADP1754/ADP1755  
ABSOLUTE MAXIMUM RATINGS  
Junction-to-ambient thermal resistance (θJA) of the package is  
based on modeling and calculation using a 4-layer board. The  
junction-to-ambient thermal resistance is highly dependent  
on the application and board layout. In applications where high  
maximum power dissipation exists, close attention to thermal  
board design is required. The value of θJA may vary, depending  
on PCB material, layout, and environmental conditions. The  
specified values of θJA are based on a 4-layer, 4 in × 3 in circuit  
board. Refer to JEDEC JESD51-7 for detailed information about  
board construction. For more information, see the AN-772  
Application Note, A Design and Manufacturing Guide for the  
Lead Frame Chip Scale Package (LFCSP).  
Table 3.  
Parameter  
Rating  
VIN to GND  
VOUT to GND  
EN to GND  
SS to GND  
−0.3 V to +4.0 V  
−0.3 V to VIN  
−0.3 V to VIN  
−0.3 V to VIN  
−0.3 V to +4.0 V  
−0.3 V to VIN  
−65°C to +150°C  
−40°C to +125°C  
150°C  
PG to GND  
SENSE/ADJ to GND  
Storage Temperature Range  
Junction Temperature Range  
Junction Temperature  
Soldering Conditions  
JEDEC J-STD-020  
Ψ
JB is the junction-to-board thermal characterization parameter  
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.  
with units of °C /W. ΨJB of the package is based on modeling and  
calculation using a 4-layer board. The JESD51-12 document,  
Guidelines for Reporting and Using Electronic Package Thermal  
Information, states that thermal characterization parameters are  
not the same as thermal resistances. ΨJB measures the component  
power flowing through multiple thermal paths rather than through  
a single path as in thermal resistance, θJB. Therefore, ΨJB thermal  
paths include convection from the top of the package as well as  
radiation from the package, factors that make ΨJB more useful in  
real-world applications. Maximum junction temperature (TJ)  
is calculated from the board temperature (TB) and the power  
dissipation (PD) using the following formula:  
THERMAL DATA  
Absolute maximum ratings apply individually only, not in  
combination. The ADP1754/ADP1755 may be damaged if 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 need to be derated. 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.  
TJ = TB + (PD × ΨJB)  
Refer to the JEDEC JESD51-8 and JESD51-12 documents for more  
detailed information about ΨJB.  
THERMAL RESISTANCE  
θJA and ΨJB are specified for the worst-case conditions, that is, a  
device soldered in a circuit board for surface-mount packages.  
The junction temperature (TJ) of the device is dependent on the  
ambient temperature (TA), the power dissipation of the device  
(PD), and the junction-to-ambient thermal resistance of the  
package (θJA). TJ is calculated using the following formula:  
Table 4. Thermal Resistance  
Package Type  
θJA  
ΨJB  
Unit  
16-Lead LFCSP with Exposed Pad (CP-16-4) 42  
25.5 °C/W  
TJ = TA + (PD × θJA)  
ESD CAUTION  
Rev. F | Page 5 of 20  
 
 
 
 
ADP1754/ADP1755  
Data Sheet  
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS  
PIN 1  
PIN 1  
INDICATOR  
INDICATOR  
12 VOUT  
11 VOUT  
10 VOUT  
12 VOUT  
11 VOUT  
10 VOUT  
VIN  
VIN  
VIN  
EN  
1
2
3
4
VIN  
VIN  
VIN  
EN  
1
2
3
4
ADP1754  
TOP VIEW  
(Not to Scale)  
ADP1755  
TOP VIEW  
(Not to Scale)  
9
SENSE  
9 ADJ  
NOTES  
1. NC = NO CONNECT.  
2. THE EXPOSED PAD ON THE BOTTOM OF THE LFCSP ENHANCES  
THERMAL PERFORMANCE AND IS ELECTRICALLY CONNECTED TO GND  
INSIDE THE PACKAGE. IT IS RECOMMENDED THAT THE EXPOSED PAD  
BE CONNECTED TO THE GROUND PLANE ON THE BOARD.  
NOTES  
1. NC = NO CONNECT.  
2. THE EXPOSED PAD ON THE BOTTOM OF THE LFCSP ENHANCES  
THERMAL PERFORMANCE AND IS ELECTRICALLY CONNECTED TO GND  
INSIDE THE PACKAGE. IT IS RECOMMENDED THAT THE EXPOSED PAD  
BE CONNECTED TO THE GROUND PLANE ON THE BOARD.  
Figure 3. ADP1754 Pin Configuration  
Figure 4. ADP1755 Pin Configuration  
Table 5. Pin Function Descriptions  
ADP1754  
Pin No.  
ADP1755  
Pin No.  
Mnemonic Description  
1, 2, 3, 15,  
16  
4
1, 2, 3, 15,  
16  
4
VIN  
EN  
PG  
Regulator Input Supply. Bypass VIN to GND with a 4.7 µF or greater capacitor. Note that all five  
VIN pins must be connected to the source.  
Enable Input. Drive EN high to turn on the regulator; drive it low to turn off the regulator. For  
automatic startup, connect EN to VIN.  
Power Good. This open-drain output requires an external pull-up resistor to VIN. If the part is in  
shutdown mode, current-limit mode, thermal shutdown, or if it falls below 90% of the nominal  
output voltage, PG immediately transitions low.  
5
5
6
7
8
9
6
7
8
N/A  
GND  
SS  
NC  
Ground.  
Soft Start. A capacitor connected to this pin determines the soft start time.  
Not Connected. No internal connection.  
Sense. This pin measures the actual output voltage at the load and feeds it to the error  
amplifier. Connect SENSE as close as possible to the load to minimize the effect of IR drop  
between the regulator output and the load.  
SENSE  
N/A  
9
ADJ  
Adjust. A resistor divider from VOUT to ADJ sets the output voltage.  
10, 11, 12,  
13, 14  
10, 11, 12,  
13, 14  
VOUT  
Regulated Output Voltage. Bypass VOUT to GND with a 4.7 µF or greater capacitor. Note that all  
five VOUT pins must be connected to the load.  
17 (EPAD)  
17 (EPAD)  
Exposed  
paddle  
(EPAD)  
The exposed pad on the bottom of the LFCSP package enhances thermal performance and is  
electrically connected to GND inside the package. It is recommended that the exposed pad be  
connected to the ground plane on the board.  
Rev. F | Page 6 of 20  
 
Data Sheet  
ADP1754/ADP1755  
TYPICAL PERFORMANCE CHARACTERISTICS  
VIN = 1.9 V, VOUT = 1.5 V, IOUT = 10 mA, CIN = 4.7 µF, COUT = 4.7 µF, TA = 25°C, unless otherwise noted.  
1.520  
1.515  
1.510  
1.505  
1.500  
1.495  
1.490  
1.485  
1.480  
1200  
1000  
800  
600  
400  
200  
0
LOAD = 1.2A  
LOAD = 10mA  
LOAD = 100mA  
LOAD = 400mA  
LOAD = 800mA  
LOAD = 1.2A  
LOAD = 800mA  
LOAD = 400mA  
LOAD = 100mA  
LOAD = 10mA  
–40  
–5  
25  
85  
125  
–40  
–5  
25  
85  
125  
JUNCTION TEMPERATURE (°C)  
JUNCTION TEMPERATURE (°C)  
Figure 5. Output Voltage vs. Junction Temperature  
Figure 8. Ground Current vs. Junction Temperature  
1.520  
1.515  
1.510  
1.505  
1.500  
1.495  
1.490  
1.485  
1.480  
1200  
1000  
800  
600  
400  
200  
0
10  
100  
1k  
10k  
10  
100  
1k  
10k  
LOAD CURRENT (mA)  
LOAD CURRENT (mA)  
Figure 6. Output Voltage vs. Load Current  
Figure 9. Ground Current vs. Load Current  
1.520  
1.515  
1.510  
1.505  
1.500  
1.495  
1.490  
1.485  
1.480  
1200  
1000  
800  
600  
400  
200  
0
LOAD = 10mA  
LOAD = 100mA  
LOAD = 400mA  
LOAD = 800mA  
LOAD = 1.2A  
LOAD = 1.2A  
LOAD = 800mA  
LOAD = 400mA  
LOAD = 100mA  
LOAD = 10mA  
1.8  
2.0  
2.2  
2.4  
2.6  
2.8  
3.0  
3.2  
3.4  
3.6  
1.8  
2.0  
2.2  
2.4  
2.6  
2.8  
3.0  
3.2  
3.4  
3.6  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
Figure 7. Output Voltage vs. Input Voltage  
Figure 10. Ground Current vs. Input Voltage  
Rev. F | Page 7 of 20  
 
 
ADP1754/ADP1755  
Data Sheet  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
4500  
4000  
3500  
3000  
2500  
2000  
1500  
1000  
500  
LOAD = 10mA  
LOAD = 100mA  
LOAD = 400mA  
LOAD = 800mA  
LOAD = 1.2A  
1.9V  
2.0V  
2.4V  
2.6V  
3.0V  
3.6V  
0
–40  
–15  
10  
35  
60  
85  
2.3  
2.4  
2.5  
2.6  
2.7  
2.8  
TEMPERATURE (°C)  
INPUT VOLTAGE (V)  
Figure 11. Shutdown Current vs. Temperature at Various Input Voltages  
Figure 14. Ground Current vs. Input Voltage (in Dropout), VOUT = 2.5 V  
0.14  
0.12  
0.10  
0.08  
T
I
LOAD  
1
2
1mA TO 1.2A LOAD STEP, 2.5A/µs, 500mA/DIV  
V
OUT  
0.06  
0.04  
50mV/DIV  
1.6V  
2.5V  
0.02  
V
V
= 3.6V  
= 1.5V  
IN  
OUT  
0
B
B
W
CH1 500mA Ω  
CH2 50mV  
M10µs A CH1  
380mA  
W
1
10  
100  
1k  
10k  
T
10.40%  
LOAD CURRENT (mA)  
Figure 12. Dropout Voltage vs. Load Current, VOUT = 1.6 V, 2.5 V  
Figure 15. Load Transient Response, CIN = 4.7 µF, COUT = 4.7 µF  
2.60  
2.55  
2.50  
2.45  
2.40  
2.35  
T
I
LOAD  
1mA TO 1.2A LOAD STEP, 2.5A/µs,  
500mA/DIV  
1
2
V
OUT  
LOAD = 10mA  
LOAD = 100mA  
LOAD = 400mA  
2.30  
20mV/DIV  
2.25  
V
V
= 3.6V  
= 1.5V  
IN  
OUT  
LOAD = 800mA  
LOAD = 1.2A  
2.20  
2.3  
B
B
W
CH1 500mA Ω  
CH2 20mV  
M10µs  
A CH1  
340mA  
W
2.4  
2.5  
2.6  
2.7  
2.8  
T
10.20%  
INPUT VOLTAGE (V)  
Figure 16. Load Transient Response, CIN = 22 µF, COUT = 22 µF  
Figure 13. Output Voltage vs. Input Voltage (in Dropout), VOUT = 2.5 V  
Rev. F | Page 8 of 20  
Data Sheet  
ADP1754/ADP1755  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
T
1.2A  
V
IN  
800mA  
400mA  
100mA  
10mA  
3V TO 3.5V INPUT VOLTAGE STEP, 2V/µs  
V
OUT  
2
5mV/DIV  
V
C
= 1.5V  
OUT  
= C  
= 4.7µF  
IN  
OUT  
1
B
B
W
CH1 500mV  
CH2 5mV  
M10µs  
9.60%  
A CH4  
800mV  
W
10  
100  
1k  
10k  
100k  
1M  
10M  
T
FREQUENCY (Hz)  
Figure 17. Line Transient Response, Load Current = 1200 mA  
Figure 20. Power Supply Rejection Ratio vs. Frequency,  
OUT = 0.75 V, VIN = 1.75 V  
V
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
70  
1.2A  
2.5V  
800mA  
400mA  
100mA  
10mA  
60  
50  
40  
30  
20  
10  
1.5V  
0.75V  
0
10  
100  
1k  
10k  
100k  
1M  
10M  
0.0001  
0.001  
0.01  
0.1  
1
10  
FREQUENCY (Hz)  
LOAD CURRENT (A)  
Figure 21. Power Supply Rejection Ratio vs. Frequency,  
OUT = 1.5 V, VIN = 2.5 V  
Figure 18. Noise vs. Load Current and Output Voltage  
V
10  
0
–10  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
–100  
1.2A  
800mA  
400mA  
100mA  
10mA  
1
1.5V  
2.5V  
0.1  
0.75V  
0.01  
10  
100  
1k  
10k  
100k  
10  
100  
1k  
10k  
100k  
1M  
10M  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
Figure 19. Noise Spectral Density vs. Output Voltage, ILOAD = 10 mA  
Figure 22. Power Supply Rejection Ratio vs. Frequency,  
OUT = 2.5 V, VIN = 3.5 V  
V
Rev. F | Page 9 of 20  
ADP1754/ADP1755  
Data Sheet  
0
1.5V/1200mA  
2.5V/1200mA  
1.5V/10mA  
2.5V/10mA  
0.75V/10mA  
–10  
0.75V/1200mA  
–20  
–30  
–40  
–50  
–60  
–70  
–80  
–90  
10  
100  
1k  
10k  
100k  
1M  
10M  
FREQUENCY (Hz)  
Figure 23. Power Supply Rejection Ratio vs. Frequency and Output Voltage  
Rev. F | Page 10 of 20  
Data Sheet  
ADP1754/ADP1755  
THEORY OF OPERATION  
The ADP1754 is available in seven fixed output voltage options  
between 0.75 V and 2.5 V. The ADP1754 allows for connection  
of an external soft start capacitor that controls the output  
voltage ramp during startup. The ADP1755 is the adjustable  
version with an output voltage that can be set to a value  
between 0.75 V and 3.3 V by an external voltage divider. Both  
devices are controlled by an enable pin (EN).  
The ADP1754/ADP1755 are low dropout linear regulators that  
use an advanced, proprietary architecture to provide high power  
supply rejection ratio (PSRR) and excellent line and load transient  
response with only a small 4.7 µF ceramic output capacitor. Both  
devices operate from a 1.6 V to 3.6 V input rail and provide up  
to 1.2 A of output current. Supply current in shutdown mode is  
typically 2 µA.  
SOFT START FUNCTION (ADP1754/ADP1755)  
REVERSE POLARITY  
ADP1754  
PROTECTION  
For applications that require a controlled startup, the ADP1754/  
ADP1755 provide a programmable soft start function. The  
programmable soft start is useful for reducing inrush current  
upon startup and for providing voltage sequencing. To implement  
soft start, connect a small ceramic capacitor from SS to GND.  
Upon startup, a 0.9 µA current source charges this capacitor.  
The ADP1754/ADP1755 start-up output voltage is limited by  
the voltage at SS, providing a smooth ramp-up to the nominal  
output voltage. The soft start time is calculated as follows:  
VIN  
VOUT  
UVLO  
GND  
SHORT-CIRCUIT  
AND THERMAL  
PROTECTION  
SENSE  
R1  
R2  
0.5V  
REF  
PG  
EN  
t
SS = VREF × (CSS/ISS)  
where:  
SS is the soft start period.  
REF is the 0.5 V reference voltage.  
SS is the soft start capacitance from SS to GND.  
SS is the current sourced from SS (0.9 µA).  
(1)  
PG  
DETECT  
0.9µA  
SS  
SHUTDOWN  
t
V
C
I
Figure 24. ADP1754 Internal Block Diagram  
REVERSE POLARITY  
ADP1755  
When the ADP1754/ADP1755 is disabled (using the EN pin), the  
PROTECTION  
soft start capacitor is discharged to GND through an internal 100 Ω  
VIN  
VOUT  
resistor.  
UVLO  
2.50  
2.25  
GND  
EN  
SHORT-CIRCUIT  
AND THERMAL  
PROTECTION  
2.00  
1.75  
1nF  
1.50  
ADJ  
SS  
0.5V  
REF  
PG  
EN  
1.25  
4.7nF  
PG  
DETECT  
1.00  
0.9µA  
10nF  
0.75  
SHUTDOWN  
0.50  
0.25  
0
Figure 25. ADP1755 Internal Block Diagram  
Internally, the ADP1754/ADP1755 consist of a reference, an  
error amplifier, a feedback voltage divider, and a PMOS pass  
transistor. Output current is delivered via the PMOS pass  
transistor, which is controlled by the error amplifier. The error  
amplifier compares the reference voltage with the feedback  
voltage from the output and amplifies the difference. If the  
feedback voltage is lower than the reference voltage, the gate  
of the PMOS device is pulled lower, allowing more current  
to pass and increasing the output voltage. If the feedback  
voltage is higher than the reference voltage, the gate of the  
PMOS device is pulled higher, allowing less current to pass  
and decreasing the output voltage.  
0
2
4
6
8
10  
TIME (ms)  
Figure 26. VOUT Ramp-Up with External Soft Start Capacitor  
Rev. F | Page 11 of 20  
 
 
ADP1754/ADP1755  
Data Sheet  
T
As shown in Figure 28, the EN pin has hysteresis built in. This  
hysteresis prevents on/off oscillations that can occur due to  
noise on the EN pin as it passes through the threshold points.  
EN  
1
The EN pin active/inactive thresholds are derived from the VIN  
voltage. Therefore, these thresholds vary with changing input  
voltage. Figure 29 shows typical EN active/inactive thresholds  
when the input voltage varies from 1.6 V to 3.6 V.  
1.1  
V
OUT  
1.0  
2
V
C
= 1.5V  
OUT  
= C  
500mV/DIV  
B
= 4.7µF  
IN  
OUT  
0.9  
B
CH1 2.0V  
CH2 500mV  
M40µs  
W
A
CH1  
920mV  
W
EN ACTIVE  
T
9.8%  
0.8  
Figure 27. VOUT Ramp-Up with Internal Soft Start  
EN INACTIVE  
ADJUSTABLE OUTPUT VOLTAGE (ADP1755)  
0.7  
The output voltage of the ADP1755 can be set over a 0.75 V to  
3.3 V range. The output voltage is set by connecting a resistive  
voltage divider from VOUT to ADJ. The output voltage is calcu-  
lated using the following equation:  
0.6  
0.5  
1.6  
1.8  
2.0  
2.2  
2.4  
2.6  
2.8  
3.0  
3.2  
3.4  
3.6  
INPUT VOLTAGE (V)  
V
OUT = 0.5 V × (1 + R1/R2)  
(2)  
Figure 29. Typical EN Pin Thresholds vs. Input Voltage  
where:  
R1 is the resistor from VOUT to ADJ.  
R2 is the resistor from ADJ to GND.  
POWER-GOOD FEATURE  
The ADP1754/ADP1755 provide a power-good pin, PG, to  
indicate the status of the output. This open-drain output  
requires an external pull-up resistor to VIN. If the part is in  
shutdown mode, current-limit mode, thermal shutdown, or  
if it falls below 90% of the nominal output voltage, PG imme-  
diately transitions low. During soft start, the rising threshold of  
the power-good signal is 93.5% of the nominal output voltage.  
The maximum bias current into ADJ is 150 nA. Therefore, to  
achieve less than 0.5% error due to the bias current, use values  
less than 60 kΩ for R2.  
ENABLE FEATURE  
The ADP1754/ADP1755 use the EN pin to enable and disable  
the VOUT pins under normal operating conditions. As shown  
in Figure 28, when a rising voltage on EN crosses the active  
threshold, VOUT turns on. When a falling voltage on EN crosses  
the inactive threshold, VOUT turns off.  
The open-drain output is held low when the ADP1754/ADP1755  
have sufficient input voltage to turn on the internal PG transistor.  
An optional soft start delay can be detected. The PG transistor  
is terminated via a pull-up resistor to VOUT or VIN.  
T
Power-good accuracy is 93.5% of the nominal regulator output  
voltage when this voltage is rising, with a 90% trip point when  
this voltage is falling.  
EN  
Regulator input voltage brownouts or glitches trigger a power  
no-good if VOUT falls below 90%.  
V
OUT  
A normal power-down triggers a power no-good when VOUT  
drops below 90%.  
1
V
C
= 1.5V  
OUT  
= C  
500mV/DIV  
B
= 4.7µF  
IN  
OUT  
B
CH1 500mV  
CH2 500mV  
M2.0ms  
W
A
CH1  
1.05V  
W
T
29.6%  
Figure 28. Typical EN Pin Operation  
Rev. F | Page 12 of 20  
 
 
 
 
 
Data Sheet  
ADP1754/ADP1755  
T
REVERSE CURRENT PROTECTION FEATURE  
V
IN  
1V/DIV  
The ADP1754/ADP1755 have additional circuitry to protect  
against reverse current flow from VOUT to VIN. For a typical  
LDO with a PMOS pass device, there is an intrinsic body diode  
between VIN and VOUT. When VIN is greater than VOUT, this  
diode is reverse-biased. If VOUT is greater than VIN, the intrinsic  
diode becomes forward-biased and conducts current from VOUT  
to VIN, potentially causing destructive power dissipation. The  
reverse current protection circuitry detects when VOUT is greater  
than VIN and reverses the direction of the intrinsic diode connec-  
tion, reverse-biasing the diode. The gate of the PMOS pass  
device is also connected to VOUT, keeping the device off.  
1
V
OUT  
500mV/DIV  
PG  
1V/DIV  
2
V
C
= 1.5V  
OUT  
= C  
= 4.7µF  
IN  
OUT  
B
B
CH1 1.0V  
CH3 1.0V  
CH2 500mV  
M40.0µs A CH3  
W
900mV  
W
W
B
T
50.40%  
Figure 32 shows a plot of the reverse current vs. the VOUT to VIN  
Figure 30. Typical PG Behavior vs. VOUT, VIN Rising (VOUT = 1.5 V)  
differential.  
4000  
3500  
3000  
2500  
2000  
1500  
1000  
500  
T
V
IN  
1V/DIV  
1
V
OUT  
500mV/DIV  
PG  
1V/DIV  
2
V
C
= 1.5V  
OUT  
= C  
0
= 4.7µF  
IN  
OUT  
0
0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6  
– V (V)  
V
OUT  
IN  
B
B
CH1 1.0V  
CH3 1.0V  
CH2 500mV  
M40.0µs A CH3  
W
900mV  
W
W
B
T
50.40%  
Figure 32. Reverse Current vs. VOUT − VIN  
Figure 31. Typical PG Behavior vs. VOUT, VIN Falling (VOUT = 1.5 V)  
Rev. F | Page 13 of 20  
 
 
ADP1754/ADP1755  
Data Sheet  
APPLICATIONS INFORMATION  
CAPACITOR SELECTION  
Input Bypass Capacitor  
Connecting a 4.7 µF capacitor from the VIN pin to GND  
reduces the circuit sensitivity to printed circuit board (PCB)  
layout, especially when long input traces or high source  
impedance are encountered. If output capacitance greater than  
4.7 µF is required, it is recommended that the input capacitor be  
increased to match it.  
Output Capacitor  
The ADP1754/ADP1755 are designed for operation with small,  
space-saving ceramic capacitors, but they can function with most  
commonly used capacitors as long as care is taken with the  
effective series resistance (ESR) value. The ESR of the output  
capacitor affects the stability of the LDO control loop. A mini-  
mum of 3.3 µF capacitance with an ESR of 500 mΩ or less is  
recommended to ensure the stability of the ADP1754/ADP1755.  
Transient response to changes in load current is also affected by  
output capacitance. Using a larger value of output capacitance  
improves the transient response of the ADP1754/ADP1755 to  
large changes in load current. Figure 33 and Figure 34 show the  
transient responses for output capacitance values of 4.7 µF and  
22 µF, respectively.  
Input and Output Capacitor Properties  
Any good quality ceramic capacitors can be used with the  
ADP1754, as long as they meet the minimum capacitance and  
maximum ESR requirements. Ceramic capacitors are manufac-  
tured 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 recom-  
mended. Y5V and Z5U dielectrics are not recommended, due  
to their poor temperature and dc bias characteristics.  
T
I
LOAD  
Figure 35 shows the capacitance vs. voltage bias characteristics  
of an 0805 case, 4.7 µF, 10 V, X5R capacitor. The voltage stability  
of a capacitor is strongly influenced by the capacitor size and  
voltage rating. In general, a capacitor in a larger package or with  
a higher voltage rating exhibits better stability. The temperature  
variation of the X5R dielectric is about 15% over the −40°C to  
+85°C temperature range and is not a function of package size  
or voltage rating.  
1mA TO 1.2A LOAD STEP, 2.5A/µs, 500mA/DIV  
1
2
V
OUT  
50mV/DIV  
V
C
= 3.6V, V  
= C  
OUT  
= 1.5V  
= 4.7µF  
IN  
OUT  
IN  
5
MURATA P/N GRM219R61A475KE34  
B
B
W
CH1 500mA  
CH2 50mV  
M1µs  
A CH1 380mA  
W
T
11.2%  
4
3
2
1
0
Figure 33. Output Transient Response, COUT = 4.7 µF  
T
I
LOAD  
1mA TO 1.2A LOAD STEP, 2.5A/µs, 500mA/DIV  
1
2
V
OUT  
20mV/DIV  
0
2
4
6
8
10  
VOLTAGE BIAS (V)  
V
C
= 3.6V, V  
= C  
OUT  
= 1.5V  
= 22µF  
IN  
OUT  
Figure 35. Capacitance vs. Voltage Bias Characteristics  
IN  
B
B
W
Equation 3 can be used to determine the worst-case capacitance,  
accounting for capacitor variation over temperature, component  
tolerance, and voltage.  
CH1 500mA  
CH2 20mV  
M1µs  
A CH1 340mA  
W
T
11.0%  
Figure 34. Output Transient Response, COUT = 22 µF  
CEFF = COUT × (1 − TEMPCO) × (1 − TOL)  
(3)  
where:  
C
EFF is the effective capacitance at the operating voltage.  
TEMPCO is the worst-case capacitor temperature coefficient.  
TOL is the worst-case component tolerance.  
Rev. F | Page 14 of 20  
 
 
 
 
 
Data Sheet  
ADP1754/ADP1755  
In this example, the worst-case temperature coefficient  
THERMAL CONSIDERATIONS  
(TEMPCO) over −40°C to +85°C is assumed to be 15% for an  
X5R dielectric. The tolerance of the capacitor (TOL) is assumed  
to be 10%, and COUT = 4.46 μF at 1.8 V, as shown in Figure 35.  
To guarantee reliable operation, the junction temperature of the  
ADP1754/ADP1755 must not exceed 125°C. To ensure that the  
junction temperature stays below this maximum value, the user  
needs to be aware of the parameters that contribute to junction  
temperature changes. These parameters include ambient temp-  
erature, power dissipation in the power device, and thermal  
resistance between the junction and ambient air (θJA). The θJA  
value is dependent on the package assembly compounds used  
and the amount of copper to which the GND pin and the exposed  
pad (EPAD) of the package are soldered on the PCB. Table 6 shows  
typical θJA values for the 16-lead LFCSP for various PCB copper  
sizes. Table 7 shows typical ΨJB values for the 16-lead LFCSP.  
Substituting these values in Equation 3 yields  
CEFF = 4.46 μF × (1 − 0.15) × (1 − 0.1) = 3.41 μF  
Therefore, the capacitor chosen in this example meets the  
minimum capacitance requirement of the LDO over temper-  
ature and tolerance at the chosen output voltage.  
To guarantee the performance of the ADP1754/ADP1755, it is  
imperative that the effects of dc bias, temperature, and toler-  
ances on the behavior of the capacitors be evaluated for each  
application.  
Table 6. Typical θJA Values  
UNDERVOLTAGE LOCKOUT  
Copper Size (mm2)  
θJA (°C/W), LFCSP  
01  
130  
80  
69  
54  
42  
The ADP1754/ADP1755 have an internal undervoltage lockout  
circuit that disables all inputs and the output when the input  
voltage is less than approximately 1.58 V. This ensures that the  
ADP1755/ADP1755 inputs and the output behave in a predicta-  
ble manner during power-up.  
100  
500  
1000  
6400  
CURRENT-LIMIT AND THERMAL OVERLOAD  
PROTECTION  
1 Device soldered to minimum size pin traces.  
Table 7. Typical ΨJB Values  
The ADP1754/ADP1755 are protected against damage due to  
excessive power dissipation by current-limit and thermal  
overload protection circuits. The ADP1754/ADP1755 are  
designed to reach current limit when the output load reaches  
2 A (typical). When the output load exceeds 2 A, the output  
voltage is reduced to maintain a constant current limit.  
Copper Size (mm2)  
ΨJB (°C/W) @ 1 W  
100  
500  
1000  
32.7  
31.5  
25.5  
The junction temperature of the ADP1754/ADP1755 can be  
calculated from the following equation:  
Thermal overload protection is included, which limits the  
junction temperature to a maximum of 150°C (typical). Under  
extreme conditions (that is, high ambient temperature and  
power dissipation) when the junction temperature begins to  
rise above 150°C, the output is turned off, reducing the output  
current to zero. When the junction temperature drops below  
135°C (typical), the output is turned on again and the output  
current is restored to its nominal value.  
TJ = TA + (PD × θJA)  
(4)  
(5)  
where:  
TA is the ambient temperature.  
PD is the power dissipation in the die, given by  
PD = [(VIN VOUT) × ILOAD] + (VIN × IGND  
where:  
IN and VOUT are the input and output voltages, respectively.  
)
Consider the case where a hard short from VOUT to ground  
occurs. At first, the ADP1754/ADP1755 reach current limit so  
that only 2 A is conducted into the short. If self-heating of the  
junction becomes great enough to cause its temperature to  
rise above 150°C, thermal shutdown activates, turning off the  
output and reducing the output current to zero. As the junction  
temperature cools and drops below 135°C, the output turns on  
and conducts 2 A into the short, again causing the junction  
temperature to rise above 150°C. This thermal oscillation between  
135°C and 150°C causes a current oscillation between 2A and  
0 A that continues as long as the short remains at the output.  
V
I
LOAD is the load current.  
IGND is the ground current.  
Power dissipation due to ground current is quite small and can  
be ignored. Therefore, the junction temperature equation can  
be simplified as follows:  
TJ = TA + {[(VIN VOUT) × ILOAD] × θJA}  
(6)  
As shown in Equation 6, for a given ambient temperature, input-  
to-output voltage differential, and continuous load current, a  
minimum copper size requirement exists for the PCB to ensure  
that the junction temperature does not rise above 125°C.  
Current-limit and thermal overload protections are intended to  
protect the device against accidental overload conditions. For  
reliable operation, device power dissipation should be externally  
limited so that junction temperatures do not exceed 125°C.  
Figure 36 through Figure 41 show junction temperature  
calculations for different ambient temperatures, load currents,  
V
IN to VOUT differentials, and areas of PCB copper.  
Rev. F | Page 15 of 20  
 
 
 
 
 
ADP1754/ADP1755  
Data Sheet  
140  
140  
120  
100  
80  
MAX JUNCTION  
MAX JUNCTION  
TEMPERATURE  
TEMPERATURE  
120  
LOAD = 800mA  
LOAD = 1.2A  
LOAD = 800mA  
LOAD = 1.2A  
100  
LOAD = 400mA  
LOAD = 200mA  
80  
LOAD = 400mA  
60  
40  
20  
0
60  
40  
20  
0
LOAD = 200mA  
LOAD = 100mA  
LOAD = 10mA  
LOAD = 100mA  
LOAD = 10mA  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
V
– V  
OUT  
V
– V  
IN OUT  
IN  
Figure 36. 6400 mm2 of PCB Copper, TA = 25°C, LFCSP  
Figure 39. 6400 mm2 of PCB Copper, TA = 50°C, LFCSP  
140  
120  
100  
80  
140  
120  
100  
80  
MAX JUNCTION  
TEMPERATURE  
MAX JUNCTION  
LOAD = 1.2A  
TEMPERATURE  
LOAD = 1.2A  
LOAD = 800mA  
LOAD = 400mA  
LOAD = 400mA  
LOAD = 800mA  
LOAD = 200mA  
LOAD = 200mA  
LOAD = 100mA  
LOAD = 10mA  
60  
40  
20  
0
60  
40  
20  
0
LOAD = 100mA  
LOAD = 10mA  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
V
– V  
OUT  
V
– V  
IN OUT  
IN  
Figure 37. 500 mm2 of PCB Copper, TA = 25°C, LFCSP  
Figure 40. 500 mm2 of PCB Copper, TA = 50°C, LFCSP  
140  
120  
100  
80  
140  
120  
100  
80  
MAX JUNCTION  
TEMPERATURE  
MAX JUNCTION  
LOAD = 1.2A  
TEMPERATURE  
LOAD =  
800mA  
LOAD = 1.2A  
LOAD = 400mA  
LOAD = 200mA  
LOAD =  
LOAD = 400mA  
800mA  
LOAD = 200mA  
LOAD = 100mA  
LOAD = 10mA  
60  
40  
20  
0
60  
40  
20  
0
LOAD = 100mA  
LOAD = 10mA  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
V
– V  
OUT  
V
– V  
IN OUT  
IN  
Figure 38. 0 mm2 of PCB Copper, TA = 25°C, LFCSP  
Figure 41. 0 mm2 of PCB Copper, TA = 50°C, LFCSP  
In cases where the board temperature is known, the thermal  
characterization parameter, ΨJB, can be used to estimate the  
junction temperature rise. Maximum junction temperature (TJ)  
is calculated from the board temperature (TB) and power  
dissipation (PD) using the following formula:  
TJ = TB + (PD × ΨJB)  
(7)  
Rev. F | Page 16 of 20  
 
 
Data Sheet  
ADP1754/ADP1755  
140  
120  
100  
80  
Figure 42 through Figure 45 show junction temperature calcula-  
tions for different board temperatures, load currents, VIN to  
MAX JUNCTION  
TEMPERATURE  
VOUT differentials, and areas of PCB copper.  
140  
MAX JUNCTION  
TEMPERATURE  
LOAD = 1.2A  
LOAD = 800mA  
120  
LOAD = 1.2A  
LOAD = 800mA  
100  
60  
40  
20  
0
LOAD = 400mA  
LOAD = 200mA  
80  
LOAD = 400mA  
LOAD = 200mA  
LOAD = 10mA  
60  
40  
20  
0
LOAD = 100mA  
1.75  
0.25  
0.75  
1.25  
2.25  
2.75  
V
– V (V)  
OUT  
IN  
LOAD = 10mA  
Figure 44. 1000 mm2 of PCB Copper, TB = 25°C, LFCSP  
LOAD = 100mA  
140  
120  
100  
80  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
MAX JUNCTION  
TEMPERATURE  
V
– V  
OUT  
IN  
Figure 42. 500 mm2 of PCB Copper, TB = 25°C, LFCSP  
LOAD = 1.2A  
LOAD = 800mA  
140  
120  
100  
80  
MAX JUNCTION  
TEMPERATURE  
LOAD = 400mA  
LOAD = 200mA  
LOAD = 800mA  
LOAD = 1.2A  
60  
40  
20  
0
LOAD = 400mA  
LOAD = 10mA  
LOAD = 100mA  
LOAD = 200mA  
LOAD = 10mA  
60  
40  
20  
0
LOAD = 100mA  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
V
– V  
OUT  
IN  
Figure 45. 1000 mm2 of PCB Copper, TB = 50°C, LFCSP  
0.25  
0.75  
1.25  
1.75  
(V)  
2.25  
2.75  
V
– V  
OUT  
IN  
Figure 43. 500 mm2 of PCB Copper, TB = 50°C, LFCSP  
Rev. F | Page 17 of 20  
 
 
ADP1754/ADP1755  
Data Sheet  
PCB LAYOUT CONSIDERATIONS  
Heat dissipation from the package can be improved by increas-  
ing the amount of copper attached to the pins of the ADP1754/  
ADP1755. However, as shown in Table 6, a point of diminishing  
returns is eventually reached, beyond which an increase in the  
copper size does not yield significant heat dissipation benefits.  
Here are a few general tips when designing PCBs:  
Place the input capacitor as close as possible to the VIN  
and GND pins.  
Place the output capacitor as close as possible to the VOUT  
and GND pins.  
Place the soft start capacitor as close as possible to the SS pin.  
Connect the load as close as possible to the VOUT and  
SENSE pins (ADP1754) or to the VOUT and ADJ pins  
(ADP1755).  
Use of 0603 or 0805 size capacitors and resistors achieves the  
smallest possible footprint solution on boards where area is  
limited.  
Figure 47. Typical Board Layout—Top Side  
Figure 48. Typical Board Layout—Bottom Side  
Figure 46. Evaluation Board  
Rev. F | Page 18 of 20  
 
Data Sheet  
ADP1754/ADP1755  
OUTLINE DIMENSIONS  
4.10  
4.00 SQ  
3.90  
0.60 MAX  
1.95 REF  
0.60 MAX  
PIN 1  
INDICATOR  
13  
12  
16  
1
PIN 1  
INDICATOR  
2.25  
2.10 SQ  
1.95  
3.75 BSC  
SQ  
0.65  
BSC  
EXPOSED  
PAD  
9
4
8
5
0.75  
0.60  
0.50  
0.25 MIN  
BOTTOM VIEW  
TOP VIEW  
0.80 MAX  
0.65 TYP  
12° MAX  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION AND  
FUNCTION DESCRIPTIONS  
1.00  
0.85  
0.80  
0.05 MAX  
0.02 NOM  
SECTION OF THIS DATA SHEET.  
COPLANARITY  
0.08  
0.35  
0.30  
0.25  
SEATING  
PLANE  
0.20 REF  
COMPLIANT TO JEDEC STANDARDS MO-220-VGGC  
Figure 49. 16-Lead Lead Frame Chip Scale Package [LFCSP_VQ]  
4 mm × 4 mm Body, Very Thin Quad  
(CP-16-4)  
Dimensions shown in millimeters  
ORDERING GUIDE  
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  
Output Voltage (V)  
Package Description  
Package Option  
CP-16-4  
CP-16-4  
CP-16-4  
CP-16-4  
CP-16-4  
CP-16-4  
CP-16-4  
CP-16-4  
ADP1754ACPZ-0.75R7  
ADP1754ACPZ-1.0-R7  
ADP1754ACPZ-1.1-R7  
ADP1754ACPZ-1.2-R7  
ADP1754ACPZ-1.3-R7  
ADP1754ACPZ-1.5-R7  
ADP1754ACPZ-1.8-R7  
ADP1754ACPZ-2.5-R7  
ADP1755ACPZ-R7  
0.75  
1.0  
1.1  
1.2  
1.3  
1.5  
1.8  
2.5  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
16-Lead LFCSP_VQ  
Evaluation Board  
Evaluation Board  
Adjustable from 0.75 to 3.3  
1.5  
Adjustable  
CP-16-4  
ADP1754-1.5-EVALZ  
ADP1755-EVALZ  
1 Z = RoHS Compliant Part.  
Rev. F | Page 19 of 20  
 
 
 
ADP1754/ADP1755  
NOTES  
Data Sheet  
©2008–2013 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D07722-0-8/13(F)  
Rev. F | Page 20 of 20  

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