ISL8018EVAL3Z [INTERSIL]

8A Low Quiescent Current High Efficiency Synchronous Buck Regulator;
ISL8018EVAL3Z
型号: ISL8018EVAL3Z
厂家: Intersil    Intersil
描述:

8A Low Quiescent Current High Efficiency Synchronous Buck Regulator

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DATASHEET  
8A Low Quiescent Current High Efficiency Synchronous  
Buck Regulator  
ISL8018  
Features  
The ISL8018 is a high efficiency, monolithic, synchronous  
step-down DC/DC converter that can deliver up to 8A continuous  
output current from a 2.7V to 5.5V input supply. The output  
• High efficiency synchronous buck regulator with up to 97%  
efficiency  
• ±10% output voltage margining  
• Adjustable current limit  
voltage is adjustable from 0.6V to V . With an adjustable current  
limit, reverse current protection, prebias start and  
IN  
over-temperature protection, the ISL8018 offers a highly robust  
power solution. It uses current control architecture to deliver fast  
transient response and excellent loop stability.  
• Start-up with prebiased output  
• Internal soft-start - 1ms or adjustable, internal/external  
compensation  
The ISL8018 integrates a pair of low ON-resistance P-channel  
and N-channel internal MOSFETs to maximize efficiency and  
minimize external component count. 100% duty-cycle operation  
allows less than 250mV dropout at 8A output current. Adjustable  
frequency and synchronization allow the ISL8018 to be used in  
applications requiring low noise.  
• Soft-stop output discharge during disabled  
• Adjustable frequency from 500kHz to 4MHz - default at 1MHz  
• External synchronization up to 4MHz - master to slave phase  
shifting capability  
• Peak current limiting, hiccup mode short-circuit protection and  
over-temperature protection  
The ISL8018 can be configured for discontinuous or forced  
continuous operation at light load. Forced continuous operation  
reduces noise and RF interference while discontinuous mode  
provides high efficiency by reducing switching losses at light loads.  
Applications  
• DC/DC POL modules  
The ISL8018 is offered in a space saving 20 Ld 3x4 QFN lead free  
package with exposed pad lead frames for excellent thermal  
performance. The complete converter occupies less than  
• µC/µP, FPGA and DSP power  
• Plug-in DC/DC modules for routers and switchers  
• Portable instruments  
2
96.8mm area.  
• Test and measurement systems  
• Li-ion battery powered devices  
See Ordering Information on page 2 for more detail.  
Related Literature  
UG052 “ISL8018DEMO1Z Demonstration Board User Guide”  
UG053 “ISL8018EVAL3Z Evaluation Board User Guide”  
100  
95  
3.3V  
OUT  
PFM  
90  
85  
80  
75  
70  
3.3V  
OUT  
PWM  
0
1
2
3
4
5
6
7
8
I
(A)  
OUT  
FIGURE 1. EFFICIENCY T = +25°C V = 5V  
IN  
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.  
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2015. All Rights Reserved  
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.  
All other trademarks mentioned are the property of their respective owners.  
1
ISL8018  
Ordering Information  
PART NUMBER  
(Notes 1, 2, 3)  
OUTPUT VOLTAGE  
(V)  
TEMP. RANGE  
(°C)  
PACKAGE  
(RoHS Compliant)  
PKG.  
DWG. #  
PART MARKING  
ISL8018IRAJZ  
018A  
Adjustable  
-40 to +85  
20 Ld 3x4 QFN  
L20.3x4  
ISL8018EVAL3Z  
ISL8018DEMO1Z  
NOTES:  
Evaluation Board  
Demonstration Board  
1. Add “-T” suffix for 6k units or “-T7A” suffix for 250 units Tape and Reel options. Please refer to TB347 for details on reel specifications.  
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte  
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil  
Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.  
3. For Moisture Sensitivity Level (MSL), please see device information page for ISL8018. For more information on MSL please see techbrief TB363.  
Pin Configuration  
ISL8018  
(20 LD QFN)  
TOP VIEW  
20  
18  
19  
17  
1
2
3
4
5
COMP  
16  
PGND  
PHASE  
PHASE  
PHASE  
VIN  
15 SS  
ISET  
14  
13  
PAD  
VSET  
FS  
12  
11  
VIN  
EN  
6
10  
8
7
9
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ISL8018  
Pin Descriptions  
PIN  
1, 19, 20  
2, 3, 4  
5, 6, 7  
8
SYMBOL  
PGND  
PHASE  
VIN  
DESCRIPTION  
Power ground.  
Switching node connection. Connect to one terminal of the inductor.  
Input supply voltage. Connect two 22µF ceramic capacitors to power ground.  
PG  
Power-good is an open-drain output. Use 10kΩ to 100kΩ pull-up resistor connected between VIN and  
PG. At power-up or EN HI, PG rising edge is delayed by 1ms from the output reaching regulation.  
9
SYNCOUT  
SYNCIN  
This pin outputs a 250µA current source that is turned on at the rising edge of the internal clock or  
SYNCIN. When SYNCOUT voltage reaches 0.8V, a reset circuit will activate and discharge SYNCOUT to  
0V. SYNCOUT is held at 0V in PFM light load to reduce quiescent current.  
10  
Mode selection pin. Connect to logic high or input voltage VIN for PWM mode. Connect to logic low or  
ground for PFM mode. Connect to an external function generator for synchronization with the positive  
edge trigger. There is an internal 1MΩ pull-down resistor to prevent an undefined logic state if SYNCIN  
is floating.  
11  
12  
EN  
FS  
Regulator enable pin. Enables the output when driven to high. Shuts down the chip and discharges the  
output capacitor when driven to low.  
This pin sets the oscillator switching frequency, using a resistor, R , from the FS pin to GND. The  
FS  
frequency of operation may be programmed between 500kHz to 4MHz. The default frequency is 1MHz  
and configured for internal compensation if FS is connected to VIN.  
13  
14  
VSET  
ISET  
VSET is the output margining setting of the regulators. Connect to SGND for -10%, keep it floating for  
no margining and connect to VIN for +10%.  
ISET is the peak output current limit and skip current limit setting of the regulators. Connect to SGND  
for 3A, to VIN for 5A and keep it floating for 8A.  
15  
SS  
SS is used to adjust the soft-start time. Set to SGND for internal 1ms rise time. Connect a capacitor  
from SS to SGND to adjust the soft-start time. Do not use more than 33nF per IC.  
16, 17  
COMP, VFB  
The feedback network of the regulator, VFB, is the negative input to the transconductance error  
amplifier. COMP is the output of the amplifier if the FS resistor is used. If internal compensation is used  
(FS = VIN), the comp pin should be tied to SGND. The output voltage is set by an external resistor divider  
connected to VFB. With a properly selected divider, the output voltage can be set to any voltage  
between VIN and the 0.6V reference. While internal compensation offers a solution for many typical  
applications, an external compensation network may offer improved performance for some designs.  
In addition to regulation, VFB is also used to determine the state of PG.  
18  
SGND  
EPAD  
Signal ground.  
The exposed pad must be connected to the SGND pin for proper electrical performance. Place as many  
vias as possible under the pad connecting to the system GND plane for optimal thermal performance.  
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ISL8018  
Typical Application Diagrams  
OUTPUT  
1.8V/8A  
L
1µH  
INPUT  
2.7V TO 5.5V  
VIN  
EN  
PHASE  
C
2
2x47µF  
ISL8018  
C
1
2x22µF  
R
1
100k  
R
200k  
C *  
3
15pF  
2
PGND  
SGND  
PG  
R
3
SYNCIN  
100k  
SYNCOUT  
FS  
VIN  
VFB  
COMP  
SS  
ISET  
* C is optional. Recommend  
3
putting a placeholder for it. Check  
loop analysis first before use.  
VSET  
FIGURE 2. TYPICAL APPLICATION DIAGRAM - SINGLE CHIP 8A  
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ISL8018  
Block Diagram  
COMP  
55pF  
FS  
SYNCIN  
SYNCOUT  
SS  
SOFT-  
SHUTDOWN  
START  
SHUTDOWN  
168k  
250µA  
VDD  
+
+
VIN  
EN  
OSCILLATOR  
VREF  
BANDGAP  
+
EAMP  
COMP  
-
P
-
PWM/PFM  
LOGIC  
PHASE  
PGND  
VSET  
VFB  
CONTROLLER  
PROTECTION  
HS DRIVER  
3pF  
LS  
DRIVER  
N
+
SLOPE
COMP  
6k  
+
-
0.8V  
-
CSA  
+
OV  
+
OCP  
-
-
0.85*VREF  
ISET  
ISET  
THRESHOLD  
+
UV  
+
SKIP  
-
PG  
1ms  
DELAY  
NEG CURRENT  
SENSING  
SGND  
ZERO-CROSS  
SENSING  
-
SCP  
+
0.1V  
100  
SHUTDOWN  
FIGURE 3. FUNCTIONAL BLOCK DIAGRAM  
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ISL8018  
Absolute Maximum Ratings (Reference to GND)  
Thermal Information  
VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 5.8V (DC) or 7V (20ms)  
EN, FS, ISET, PG, SYNCOUT, SYNCIN VFB, VSET . . . . . . -0.3V to VIN + 0.3V  
PHASE . . . . . . . . . . . . -1.5V (100ns)/-0.3V (DC) to 6.5V (DC) or 7V (20ms)  
COMP, SS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 2.7V  
ESD Rating  
Thermal Resistance (Typical)  
3x4 QFN Package (Notes 4, 5) . . . . . . . . . .  
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-55°C to +125°C  
Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C  
Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB493  
(°C/W)  
42  
(°C/W)  
5
JA  
JC  
Human Body Model (Tested per JESD22-A114) . . . . . . . . . . . . . . . . . 3kV  
Machine Model (Tested per JESD22-A115). . . . . . . . . . . . . . . . . . . . 300V  
Charged Device Model (Tested per JESD22-C101E). . . . . . . . . . . . . .1.5V  
Latch-up (Tested per JESD-78A; Class 2, Level A) . . . . . .100mA at +85°C  
Recommended Operating Conditions  
VIN Supply Voltage Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.5V  
Load Current Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0A to 8A  
Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C  
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product  
reliability and result in failures not covered by warranty.  
NOTES:  
4. is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech  
JA  
Brief TB379.  
5. , “case temperature” location is at the center of the exposed metal pad on the package underside.  
JC  
Analog Specifications All parameter limits are established across the recommended operating conditions and are measured at the  
following conditions: T = -40°C to +85°C, V = 3.6V, EN = V , unless otherwise noted. Typical values are at T = +25°C. Boldface limits apply across  
A
IN  
IN  
A
the operating temperature range, -40°C to +85°C.  
MIN  
MAX  
PARAMETER  
SYMBOL  
TEST CONDITIONS  
(Note 6)  
TYP  
(Note 6)  
UNIT  
INPUT SUPPLY  
Undervoltage Lockout Threshold  
V
V
Rising, no load  
2.5  
2.4  
70  
2.7  
V
V
IN  
UVLO  
Falling, no load  
2.2  
Quiescent Supply Current  
I
SYNCIN = GND, no load at the output  
µA  
µA  
VIN  
SYNCIN = GND, no load at the output and no  
switches switching  
70  
95  
15  
SYNCIN = VIN, f  
output  
= 1MHz, no load at the  
8
5
mA  
µA  
SW  
Shutdown Supply Current  
OUTPUT REGULATION  
Reference Voltage  
I
SYNCIN = GND, V = 5.5V, EN = low  
IN  
9.5  
SD  
V
V
V
V
V
V
= V  
IN  
0.651  
0.594  
0.531  
9.5  
0.660  
0.600  
0.540  
10  
0.669  
0.606  
0.549  
10.5  
V
V
REF  
SET  
SET  
SET  
SET  
SET  
= FLOAT  
= SGND  
V
Output Voltage Margining  
V
= V , percent of output changed  
IN  
%
VFB  
= SGND, percent of output changed  
-10.5  
-10  
-9.5  
%
VFB Bias Current  
I
I
VFB = 0.75V  
0.1  
µA  
µA  
%/V  
ms  
µA  
VFB  
Fixed Output VFB Bias Current  
Line Regulation  
V
V
= FLOAT, VFB = 10% above output  
6
VFB  
SET  
= V + 0.5V to 5.5V (minimal 2.7V)  
0.2  
IN  
O
Soft-Start Ramp Time Cycle  
Soft-Start Charging Current  
OVERCURRENT PROTECTION  
Current Limit Blanking Time  
SS = SGND  
= 0.1V  
1
ISS  
V
1.4  
1.8  
2.2  
SS  
t
17  
8
Clock  
pulses  
OCON  
Overcurrent and Auto Restart Period  
t
SS cycle  
OCOFF  
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ISL8018  
Analog Specifications All parameter limits are established across the recommended operating conditions and are measured at the  
following conditions: T = -40°C to +85°C, V = 3.6V, EN = V , unless otherwise noted. Typical values are at T = +25°C. Boldface limits apply across  
A
IN  
IN  
A
the operating temperature range, -40°C to +85°C. (Continued)  
MIN  
MAX  
PARAMETER  
SYMBOL  
IPLIMIT  
TEST CONDITIONS  
(Note 6)  
TYP  
12.8  
8.8  
(Note 6)  
UNIT  
A
Positive Peak Current Limit  
I
I
I
I
I
I
= FLOAT  
9.7  
6.7  
4
15.8  
10.9  
7.2  
SET  
SET  
SET  
SET  
SET  
SET  
= V  
A
IN  
= SGND  
= FLOAT  
5.6  
A
Peak Skip Limit  
I
2.18  
1.08  
2.8  
3.78  
2.3  
A
SKIP  
= V  
1.66  
1.05  
A
IN  
= SGND  
A
Zero Cross Threshold  
-300  
300  
mA  
A
Negative Current Limit  
COMPENSATION  
INLIMIT  
-4.25  
-3  
-1.75  
Error Amplifier Transconductance  
FS = V  
IN  
100  
200  
0.11  
µA/V  
µA/V  
Ω
FS with resistor  
Transresistance  
RT  
PHASE  
P-Channel MOSFET ON-Resistance  
V
V
V
V
= 5V, I = 200mA  
31  
44  
45  
55  
35  
50  
mΩ  
mΩ  
mΩ  
mΩ  
%
IN  
IN  
IN  
IN  
O
= 2.7V, I = 200mA  
O
N-Channel MOSFET ON-Resistance  
= 5V, I = 200mA  
19  
O
= 2.7V, I = 200mA  
25  
O
PHASE Maximum Duty Cycle  
PHASE Minimum On-Time  
OSCILLATOR  
100  
SYNCIN = High  
140  
ns  
Nominal Switching Frequency  
f
FS = V  
800  
440  
1000  
520  
3700  
0.75  
0.15  
3.6  
1200  
600  
kHz  
kHz  
kHz  
V
SW  
IN  
FS with RS = 402kΩ  
FS with RS = 42.4kΩ  
3200  
0.70  
4200  
0.80  
SYNCIN Logic Low to High Transition Range  
SYNCIN Hysteresis  
V
SYNCIN Logic Input Leakage Current  
SYNCOUT Charging Current  
V
= 3.6V  
5
µA  
µA  
µA  
V
IN  
PWM  
PFM  
210  
250  
0
290  
ISO  
SYNCOUT Voltage Low  
PG  
0.3  
Output Low Voltage  
0.3  
2
V
ms  
µA  
V
Delay Time (Rising Edge)  
PG Pin Leakage Current  
OVP PG Rising Threshold  
UVP PG Rising Threshold  
UVP PG Hysteresis  
0.5  
80  
1
0.01  
0.80  
85  
5
0.1  
90  
%
%
PGOOD Delay Time (Falling Edge)  
7
µs  
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ISL8018  
Analog Specifications All parameter limits are established across the recommended operating conditions and are measured at the  
following conditions: T = -40°C to +85°C, V = 3.6V, EN = V , unless otherwise noted. Typical values are at T = +25°C. Boldface limits apply across  
A
IN  
IN  
A
the operating temperature range, -40°C to +85°C. (Continued)  
MIN  
MAX  
PARAMETER  
SYMBOL  
TEST CONDITIONS  
(Note 6)  
TYP  
(Note 6)  
UNIT  
ISET, VSET  
Logic Input Low  
0.4  
0.8  
V
V
Logic Input Float  
Logic Input High  
0.5  
0.9  
V
Logic Input Leakage Current  
EN  
0.1  
1
0.4  
1
µA  
Logic Input Low  
V
Logic Input High  
0.9  
V
EN Logic Input Leakage Current  
Thermal Shutdown  
Thermal Shutdown Hysteresis  
NOTE:  
0.1  
150  
25  
µA  
°C  
°C  
6. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.  
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ISL8018  
Typical Operating Performance Unless otherwise noted, operating conditions are: T = +25°C, V = 5V, EN = 3.3V,  
A
IN  
SYNCIN = V , L = 1µH, C = 2x22µF, C = 4x22µF, V  
= 1.8V, I = 0A to 8A.  
OUT  
IN  
1
2
OUT  
100  
100  
90  
80  
70  
60  
50  
40  
2.5V  
2.5V  
OUT  
OUT  
90  
80  
70  
60  
50  
40  
1.2V  
1.2V  
OUT  
OUT  
1.5V  
1.5V  
OUT  
OUT  
1.8V  
OUT  
1.8V  
OUT  
0
1
2
3
4
5
6
7
8
0
1
2
3
4
I
5
6
7
8
(A)  
I
(A)  
OUT  
OUT  
FIGURE 4. EFFICIENCY vs LOAD (1MHz 3.3V PWM)  
IN  
FIGURE 5. EFFICIENCY vs LOAD (1MHz 3.3V PFM)  
IN  
100  
100  
90  
80  
70  
60  
50  
40  
3.3V  
OUT  
3.3V  
OUT  
2.5V  
2.5V  
OUT  
OUT  
90  
80  
70  
60  
50  
40  
1.2V  
OUT  
1.2V  
OUT  
1.5V  
1.5V  
OUT  
OUT  
1.8V  
1.8V  
OUT  
OUT  
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
I
(A)  
I
(A)  
OUT  
OUT  
FIGURE 6. EFFICIENCY vs LOAD (1MHz 5V PWM)  
IN  
FIGURE 7. EFFICIENCY vs LOAD (1MHz 5V PFM)  
IN  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
1.815  
1.810  
1.805  
1.800  
1.795  
1.790  
1.785  
1.780  
1.775  
0A LOAD  
5V PWM MODE  
IN  
3.3V PWM MODE  
IN  
4A LOAD  
8A LOAD  
2.5 2.8  
3.1  
3.4  
3.7  
4.0  
(A)  
4.3  
4.6  
4.9  
5.2  
5.5  
0
1
2
3
4
5
6
7
8
I
(A)  
I
OUT  
OUT  
FIGURE 8. POWER DISSIPATION vs LOAD (1MHz, V  
OUT  
= 1.8V)  
FIGURE 9. V  
REGULATION vs V (PWM V = 1.8V)  
IN OUT  
OUT  
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ISL8018  
Typical Operating Performance Unless otherwise noted, operating conditions are: T = +25°C, V = 5V, EN = 3.3V,  
A
IN  
SYNCIN = V , L = 1µH, C = 2x22µF, C = 4x22µF, V  
= 1.8V, I  
OUT  
= 0A to 8A. (Continued)  
IN  
1
2
OUT  
1.847  
1.839  
1.831  
1.823  
1.815  
1.807  
1.799  
1.791  
1.783  
1.775  
1.230  
0A LOAD  
1.224  
1.218  
1.212  
1.206  
1.200  
1.194  
1.188  
1.182  
3.3V PFM MODE  
IN  
5V PFM MODE  
IN  
3.3V PWM MODE  
IN  
4A LOAD  
5V PWM MODE  
IN  
8A LOAD  
4.0 4.3  
(A)  
2.5  
2.8  
3.1  
3.4  
3.7  
4.6  
4.9  
5.2  
5.5  
0
1
2
3
4
5
6
7
8
8
8
I
I
(A)  
OUT  
OUT  
FIGURE 10. V  
OUT  
REGULATION vs V (PFM V  
IN  
= 1.8V)  
FIGURE 11. V  
REGULATION vs LOAD (1MHz, V  
= 1.2V)  
OUT  
OUT  
OUT  
1.527  
1.521  
1.515  
1.509  
1.503  
1.497  
1.491  
1.485  
1.479  
1.829  
3.3V PFM MODE  
IN  
3.3V PFM MODE  
IN  
1.822  
1.815  
1.808  
1.801  
1.794  
1.787  
1.780  
1.773  
5V PFM MODE  
IN  
5V PFM MODE  
IN  
3.3V PWM MODE  
IN  
3.3V PWM MODE  
IN  
5V PWM MODE  
5V PWM MODE  
IN  
IN  
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
8
I
(A)  
I
(A)  
OUT  
OUT  
FIGURE 12. V  
REGULATION vs LOAD (1MHz, V  
= 1.5V)  
FIGURE 13. V  
REGULATION vs LOAD (1MHz, V  
= 1.8V)  
OUT  
OUT  
OUT  
OUT  
2.532  
3.36  
5V PFM MODE  
IN  
3.3V PFM MODE  
IN  
2.524  
2.516  
2.508  
2.500  
2.492  
2.484  
2.476  
2.468  
3.35  
3.34  
3.33  
3.32  
3.31  
3.30  
3.29  
3.28  
5V PFM MODE  
IN  
5V PWM MODE  
IN  
3.3V PWM MODE  
IN  
5V PWM MODE  
IN  
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
8
I
(A)  
I
(A)  
OUT  
OUT  
FIGURE 14. V  
OUT  
REGULATION vs LOAD (1MHz, V  
= 2.5V)  
FIGURE 15. V  
OUT  
REGULATION vs LOAD (1MHz, V  
= 3.3V)  
OUT  
OUT  
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ISL8018  
Typical Operating Performance Unless otherwise noted, operating conditions are: T = +25°C, V = 5V, EN = 3.3V,  
A
IN  
SYNCIN = V , L = 1µH, C = 2x22µF, C = 4x22µF, V  
= 1.8V, I = 0A to 8A. (Continued)  
OUT  
IN  
1
2
OUT  
PHASE 2V/DIV  
PHASE 2V/DIV  
V
RIPPLE 20mV/DIV  
OUT  
V
RIPPLE 20mV/DIV  
IL 1A/DIV  
OUT  
IL 1A/DIV  
500ns/DIV  
2µs/DIV  
FIGURE 16. STEADY STATE OPERATION AT NO LOAD (PWM)  
FIGURE 17. STEADY STATE OPERATION AT NO LOAD (PFM)  
PHASE 2V/DIV  
V
RIPPLE 50mV/DIV  
OUT  
IL 2A/DIV  
V
RIPPLE 20mV/DIV  
OUT  
IL 2A/DIV  
500ns/DIV  
1ms/DIV  
FIGURE 18. STEADY STATE OPERATION WITH FULL LOAD  
FIGURE 19. LOAD TRANSIENT (PWM)  
V
RIPPLE 50mV/DIV  
OUT  
EN 2V/DIV  
V
1V/DIV  
OUT  
IL 2A/DIV  
IL 2A/DIV  
PG 5V/DIV  
1ms/DIV  
5ms/DIV  
FIGURE 20. LOAD TRANSIENT (PFM)  
FIGURE 21. SOFT-START WITH NO LOAD (PWM)  
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ISL8018  
Typical Operating Performance Unless otherwise noted, operating conditions are: T = +25°C, V = 5V, EN = 3.3V,  
A
IN  
SYNCIN = V , L = 1µH, C = 2x22µF, C = 4x22µF, V  
= 1.8V, I  
OUT  
= 0A to 8A. (Continued)  
IN  
1
2
OUT  
EN 5V/DIV  
V
1V/DIV  
OUT  
EN 2V/DIV  
V
1V/DIV  
OUT  
IL 2A/DIV  
IL 2A/DIV  
PG 5V/DIV  
PG 5V/DIV  
5ms/DIV  
5ms/DIV  
FIGURE 22. SOFT-START AT NO LOAD (PFM)  
FIGURE 23. SOFT-START WITH PREBIASED 1V  
EN 2V/DIV  
1V/DIV  
V
OUT  
EN 2V/DIV  
1V/DIV  
V
OUT  
IL 2A/DIV  
PG 5V/DIV  
IL 2A/DIV  
PG 5V/DIV  
5ms/DIV  
500µs/DIV  
FIGURE 24. SOFT-START AT FULL LOAD  
FIGURE 25. SOFT-DISCHARGE SHUTDOWN  
PHASE 5V/DIV  
PHASE 5V/DIV  
IL 2A/DIV  
V
RIPPLE 20mV/DIV  
IL 1A/DIV  
OUT  
V
RIPPLE 20mV/DIV  
OUT  
SYNC 5V/DIV  
200ns/DIV  
SYNC 5V/DIV  
200ns/DIV  
FIGURE 26. STEADY STATE OPERATION AT NO LOAD WITH  
FREQUENCY = 2MHz  
FIGURE 27. STEADY STATE OPERATION AT FULL LOAD WITH  
FREQUENCY = 2MHz  
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ISL8018  
Typical Operating Performance Unless otherwise noted, operating conditions are: T = +25°C, V = 5V, EN = 3.3V,  
A
IN  
SYNCIN = V , L = 1µH, C = 2x22µF, C = 4x22µF, V  
= 1.8V, I = 0A to 8A. (Continued)  
OUT  
IN  
1
2
OUT  
PHASE 5V/DIV  
PHASE 5V/DIV  
V
RIPPLE 20mV/DIV  
IL 2A/DIV  
OUT  
V
RIPPLE 20mV/DIV  
IL 0.2A/DIV  
OUT  
SYNC 5V/DIV  
SYNC 5V/DIV  
100ns/DIV  
100ns/DIV  
FIGURE 28. STEADY STATE OPERATION AT NO LOAD WITH  
FREQUENCY = 4MHz  
FIGURE 29. STEADY STATE OPERATION AT FULL LOAD (PWM) WITH  
FREQUENCY = 4MHz  
PHASE 5V/DIV  
PHASE 5V/DIV  
V
1V/DIV  
OUT  
V
1V/DIV  
OUT  
IL 5A/DIV  
IL 5A/DIV  
PG 5V/DIV  
PG 5V/DIV  
10µs/DIV  
2ms/DIV  
FIGURE 30. OUTPUT SHORT-CIRCUIT  
FIGURE 31. OUTPUT SHORT-CIRCUIT RECOVERY  
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ISL8018  
with the 55pF and 168kΩ RC network. The maximum EAMP  
voltage output is precisely clamped to 2.4V.  
Theory of Operation  
The ISL8018 is a step-down switching regulator optimized for  
battery-powered handheld applications. The regulator operates at  
1MHz fixed default switching frequency when FS is connected to  
VIN. By connecting a resistor from FS to SGND, the operating  
frequency may be adjusted from 500kHz to 4MHz. Unless forced  
and PWM is chosen (SYNCIN pulled HI), the regulator will allow  
PFM operation and reduce switching frequency at light loading to  
maximize efficiency. In this condition, no load quiescent is typically  
70µA.  
V
EAMP  
V
CSA  
DUTY  
CYCLE  
I
L
PWM Control Scheme  
V
OUT  
Pulling the SYNCIN high (>0.8V) forces the converter into PWM  
mode, regardless of output current. The ISL8018 employs the  
current-mode Pulse Width Modulation (PWM) control scheme for  
fast transient response and pulse-by-pulse current limiting. Figure 3  
shows the block diagram. The current loop consists of the oscillator,  
the PWM comparator, current sensing circuit and the slope  
compensation for the current loop stability. The slope compensation  
is 360mV/Ts. Current sense resistance, Rt, is typically 0.11V/A. The  
control reference for the current loop comes from the error  
amplifier's (EAMP) output.  
FIGURE 32. PWM OPERATION WAVEFORMS  
Skip Mode  
Pulling the SYNCIN pin LO (<0.4V) forces the converter into PFM  
mode. The ISL8018 enters a pulse-skipping mode at light load to  
minimize the switching loss by reducing the switching frequency.  
Figure 33 illustrates the Skip mode operation. A zero-cross  
sensing circuit shown in Figure 3 monitors the N-FET current for  
zero crossing. When 8 consecutive cycles of the inductor current  
crossing zero are detected, the regulator enters the Skip mode.  
During the eight detecting cycles, the current in the inductor is  
allowed to become negative. The counter is reset to zero when  
the current in any cycle does not cross zero.  
The PWM operation is initialized by the clock from the oscillator.  
The P-channel MOSFET is turned on at the beginning of a PWM  
cycle and the current in the MOSFET starts to ramp up. When the  
sum of the current amplifier CSA and the slope compensation  
reaches the control reference of the current loop, the PWM  
comparator EAMP output sends a signal to the PWM logic to turn  
off the P-FET and turn on the N-channel MOSFET. The N-FET stays  
on until the end of the PWM cycle. Figure 32 shows the typical  
operating waveforms during the PWM operation. The dotted lines  
illustrate the sum of the slope compensation ramp and the  
current-sense amplifier’s CSA output.  
Once the Skip mode is entered, the pulse modulation starts being  
controlled by the skip comparator shown in Figure 33. Each pulse  
cycle is still synchronized by the PWM clock. The P-FET is turned on  
at the clock's rising edge and turned off when the output is higher  
than 1.5% of the nominal regulation or when its current reaches  
the peak skip current limit value. Then the inductor current is  
discharging to 0A and stays at zero. The internal clock is disabled.  
The output voltage reduces gradually due to the load current  
discharging the output capacitor. When the output voltage drops to  
the nominal voltage, the P-FET will be turned on again at the rising  
edge of the internal clock as it repeats the previous operations.  
The output voltage is regulated by controlling the V  
EAMP  
voltage  
to the current loop. The bandgap circuit outputs a 0.6V reference  
voltage to the voltage loop. The feedback signal comes from the  
VFB pin. The soft-start block only affects the operation during the  
start-up and will be discussed separately. The error amplifier is a  
transconductance amplifier that converts the voltage error signal  
to a current output. The voltage loop is internally compensated  
The regulator resumes normal PWM mode operation when the  
output voltage drops 1.5% below the nominal voltage.  
PWM  
0.8V  
PFM  
PWM  
SYNCOUT  
CLOCK  
8 CYCLES  
PFM CURRENT LIMIT  
LOAD CURRENT  
I
L
0
NOMINAL +1.5%  
V
OUT  
NOMINAL -1.5%  
NOMINAL  
FIGURE 33. SKIP MODE OPERATION WAVEFORMS  
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Frequency Adjust  
The frequency of operation is fixed at 1MHz and internal  
PHASE1  
CLOCK1  
compensation when FS is tied to VIN. Adjustable frequency ranges  
from 500kHz to 4MHz via a simple resistor connecting FS to SGND  
according to Equation 1:  
3
0.8V  
220 10  
0.75V  
------------------------------  
(EQ. 1)  
R k =  
14  
SYNCIN_S  
T
f
kHz  
OSC  
SYNCOUT_M  
w/Cap  
Figure 34 is a graph of the measured Frequency vs RT for a VIN of  
2.7V and 5.5V.  
20nsDELAY  
PHASE2  
4200  
3500  
2800  
2100  
FIGURE 35. SYNCHRONIZATION WAVEFORMS  
Figure 36 is a graph of the master to slave phase shift vs SYNCOUT  
capacitance for 1MHz switching operation.  
300  
250  
200  
V
= 5.5V  
IN  
1400  
V
= 2.7V  
70  
IN  
700  
0
150  
0
140  
210  
280  
350  
420  
PHASE SHIFT  
MEASUREMENT  
RT (kΩ)  
100  
FIGURE 34. FREQUENCY vs RT  
50  
0
PHASE SHIFT  
CALCULATION  
Synchronization Control  
The ISL8018 can be synchronized from 500kHz to 4MHz by an  
external signal applied to the SYNCIN pin. SYNCIN frequency should  
be greater than 50% of internal clock frequency. The rising edge on  
the SYNCIN triggers the rising edge of the PHASE pulse. Make sure  
that the minimum on time of the PHASE node is greater than  
140ns.  
0
40  
80  
120  
(pF)  
160  
200  
240  
C
13  
FIGURE 36. PHASE SHIFT vs CAPACITANCE  
Overcurrent Protection  
SYNCOUT is a 250µA current pulse signal that is triggered on the  
rising edge of the clock or SYNCIN signal (whichever is greater in  
frequency). This drives other ISL8018s and avoids system beat  
frequency effects. See Figure 35 for more detail. The current  
pulse is terminated and SYNCOUT is discharged to 0V after 0.8V  
threshold is reached. SYNCOUT is 0V if the regulator operates at  
light PFM load.  
The overcurrent protection is realized by monitoring the CSA  
output with the OCP comparator, as shown in Figure 3 on page 5.  
The current sensing circuit has a gain of 0.11V/A, from the P-FET  
current to the CSA output. When the CSA output reaches a  
threshold set by ISET, the OCP comparator is tripped to turn off the  
P-FET immediately. See “Analog Specifications” on page 6 of the  
OCP threshold for various ISET configurations. The overcurrent  
function protects the switching converter from a shorted output by  
monitoring the current flowing through the upper MOSFET.  
To implement time shifting between the master circuit to the  
slave, it is recommended to add a capacitor, C as shown in  
13  
Figure 3 on page 5. The time delay from SYNCOUT_Master to  
SYNCIN_Slave as shown in Figure 3 on page 5 is calculated in pF  
using Equation 2:  
Upon detection of an overcurrent condition, the upper MOSFET  
will be immediately turned off and will not be turned on again until  
the next switching cycle. Upon detection of the initial overcurrent  
condition, the overcurrent fault counter is set to 1. If, on the  
subsequent cycle, another overcurrent condition is detected, the  
OC fault counter will be incremented. If there are 17 sequential  
OC fault detections, the regulator will be shut down under an  
overcurrent fault condition. An overcurrent fault condition will  
result in the regulator attempting to restart in a hiccup mode  
within the delay of eight soft-start periods. At the end of the eight  
soft-start wait period, the fault counters are reset and soft-start is  
attempted again. If the overcurrent condition goes away during  
the delay of eight soft-start periods, the output will resume back  
into regulation point after hiccup mode expires. When an  
C
pF= 0.333  t 20ns  
(EQ. 2)  
13  
Where t is the desired time shift between the master and the  
slave circuits in ns. Care must be taken to include PCB parasitic  
capacitance of ~3pF to 10pF.  
The maximum should be limited to 1/f -100ns to insure that  
SW  
SYNCOUT has enough time to discharge before the next cycle  
starts.  
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ISL8018  
overcurrent condition happens at low V , it is recommended to  
IN  
18  
15  
12  
9
add more input capacitance, so the valley of V is always above  
IN  
UVLO to maintain normal operation.  
Negative Current Protection  
Similar to overcurrent, the negative current protection is realized  
by monitoring the current across the low-side N-FET, as shown in  
Figure 3 on page 5. When the valley point of the inductor current  
reaches -3A for 4 consecutive cycles, both P-FET and N-FET are off.  
The 100Ω in parallel to the N-FET will activate discharging the  
output into regulation. The control will begin to switch when output  
is within regulation. The regulator will be in PFM for 20µs before  
switching to PWM if necessary.  
SS (ms)  
MEASUREMENT  
6
SS (ms)  
CALCULATION  
3
0
0
8
16  
24  
(nF)  
32  
40  
48  
C
SS  
PG  
PG is an open-drain output of a window comparator that  
FIGURE 37. SOFT-START TIME vs C  
SS  
continuously monitors the buck regulator output voltage. PG is  
actively held low when EN is low and during the buck regulator  
soft-start period. After 1ms delay of the soft-start period, PG  
becomes high impedance as long as the output voltage is within  
nominal regulation voltage set by VFB. When VFB drops 15%  
below or raises 0.8V above the nominal regulation voltage, the  
ISL8018 pulls PG low. Any fault condition forces PG low until the  
fault condition is cleared by attempts to soft-start. For logic level  
Enable  
The enable (EN) input allows the user to control the turning on or  
off of the regulator for purposes such as power-up sequencing.  
When the regulator is enabled, there is typically a 600µs delay  
for waking up the bandgap reference and then the soft start-up  
begins.  
output voltages, connect an external pull-up resistor, R , between  
PG and VIN. A 100kΩ resistor works well in most applications.  
Discharge Mode (Soft-Stop)  
1
When a transition to shutdown mode occurs or the VIN UVLO is  
set, the outputs discharge to GND through an internal 100Ω  
switch. The discharge mode is disabled if SS is tied to an external  
capacitor.  
UVLO  
When the input voltage is below the Undervoltage Lockout  
(UVLO) threshold, the regulator is disabled.  
Power MOSFETs  
The power MOSFETs are optimized for best efficiency. The  
ON-resistance for the P-FET is typically 31mΩ and the  
ON-resistance for the N-FET is typically 19mΩ.  
Soft Start-Up  
The soft start-up reduces the inrush current during the start-up.  
The soft-start block outputs a ramp reference to the input of the  
error amplifier. This voltage ramp limits the inductor current as  
well as the output voltage speed so that the output voltage rises  
in a controlled fashion. When VFB is less than 0.1V at the  
beginning of the soft-start, the switching frequency is reduced to  
200kHz so that the output can start up smoothly at light load  
condition. During soft-start, the IC operates in the Skip mode to  
support prebiased output condition.  
100% Duty Cycle  
The ISL8018 features 100% duty cycle operation to maximize  
the battery life. When the battery voltage drops to a level that the  
ISL8018 can no longer maintain the regulation at the output, the  
regulator completely turns on the P-FET. The maximum dropout  
voltage under the 100% duty cycle operation is the product of the  
load current and the ON-resistance of the P-FET.  
Tie SS to SGND for an internal soft-start of approximately 1ms.  
Connect a capacitor from SS to SGND to adjust the soft-start  
time. This capacitor, along with an internal 1.8µA current source  
Thermal Shutdown  
sets the soft-start interval of the converter, t  
.
SS  
The ISL8018 has built-in thermal protection. When the internal  
temperature reaches +150°C, the regulator is completely shut  
down. As the temperature drops to +125°C, the ISL8018 resumes  
operation by stepping through the soft-start.  
C
F= 3.33 t s  
SS  
(EQ. 3)  
SS  
C
must be less than 33nF to insure proper soft-start reset after  
SS  
fault condition. For proper use, do not prebias output voltage  
more than regulation point.  
Figure 37 is a comparison between measured and calculated  
output soft-start time versus C capacitance.  
SS  
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ISL8018  
The ISL8018 uses an internal compensation network and the  
output capacitor value is dependent on the output voltage. The  
ceramic capacitor is recommended to be X5R or X7R.  
Power Derating Characteristics  
To prevent the regulator from exceeding the maximum junction  
temperature, some thermal analysis is required. The  
temperature rise is given by Equation 4:  
For high or low output voltage applications, use external  
compensation for better phase margin.  
(EQ. 4)  
T
= PD  
JA  
RISE  
Output Voltage Selection  
Where PD is the power dissipated by the regulator and θ is the  
thermal resistance from the junction of the die to the ambient  
JA  
The output voltage of the regulator can be programmed via an  
external resistor divider that is used to scale the output voltage  
relative to the internal reference voltage and feed it back to the  
inverting input of the error amplifier (refer to Figure 2 on page 4).  
temperature. The junction temperature, T , is given by  
J
Equation 5:  
(EQ. 5)  
T
= T + T  
RISE  
The output voltage programming resistor, R , will depend on the  
2
J
A
value chosen for the feedback resistor and the desired output  
voltage of the regulator. The value for the feedback resistor is  
typically between 10kΩ and 100kΩ, as shown in Equation 7.  
Where T is the ambient temperature. For the TQFN package, the  
A
θ
is 42 (°C/W).  
JA  
V
O
VFB  
The actual junction temperature should not exceed the absolute  
maximum junction temperature of +125°C when considering  
the thermal design.  
-----------  
1  
(EQ. 7)  
R
= R  
2
3
If the output voltage desired is 0.6V, then R is left unpopulated  
3
8
and R is shorted. There is a leakage current from VIN to  
2
PHASE. It is recommended to preload the output with 10µA  
3.3V  
minimum. Capacitance, C , may be added to improve transient  
3
6
performance. A good starting point for C can be determined by  
choosing a value that provides an 80kHz corner frequency  
3
1.8V  
with R .  
0.6V  
2
4
VSET marginally adjusts VFB according to the “Analog  
Specifications” on page 6.  
2
0
Figure 39 is the recommended minimum output voltage setting  
vs operational frequency in order to avoid the minimum on-time  
specification.  
50  
60  
70  
80  
90  
100  
110  
120  
130  
3.0  
2.5  
TEMPERATURE (°C)  
FIGURE 38. DERATING CURVE vs TEMPERATURE  
V
= 5V  
IN  
2.0  
1.5  
Applications Information  
Output Inductor and Capacitor Selection  
To consider steady state and transient operations, ISL8018  
1.0  
0.5  
0.0  
typically uses a 1µH output inductor. The higher or lower inductor  
value can be used to optimize the total converter system  
performance. For example, for higher output voltage 3.3V  
application, in order to decrease the inductor current ripple and  
output voltage ripple, the output inductor value can be increased.  
It is recommended to set the ripple inductor current  
approximately 30% of the maximum output current for optimized  
performance. The inductor ripple current can be expressed as  
shown in Equation 6:  
V
= 3.3V  
3.0  
IN  
0.5  
1.0  
1.5  
2.0  
2.5  
3.5  
4.0  
FREQUENCY (MHz)  
FIGURE 39. MINIMUM V  
OUT  
vs FREQUENCY  
Input Capacitor Selection  
The main functions for the input capacitor are to provide  
decoupling of the parasitic inductance and a filtering function to  
prevent the switching current flowing back to the battery rail. At  
least two 22µF X5R or X7R ceramic capacitors are a good  
starting point for the input capacitor selection.  
V
O
---------  
V
1 –  
O
V
IN  
(EQ. 6)  
--------------------------------------  
I =  
L f  
SW  
The inductor’s saturation current rating needs to be at least  
larger than the peak current. The ISL8018 protects the typical  
peak current of 12A. The saturation current needs be over 16A  
for maximum output current application.  
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ISL8018  
Figure 41 shows the type II compensator and its transfer function  
is expressed as shown in Equation 8:  
Loop Compensation Design  
When there is an external resistor connected from FS to SGND,  
the COMP pin is active for external loop compensation. The  
ISL8018 uses constant frequency peak current mode control  
architecture to achieve fast loop transient response. An accurate  
current sensing pilot device in parallel with the upper MOSFET is  
used for peak current control signal and overcurrent protection.  
The inductor is not considered as a state variable since its peak  
current is constant and the system becomes a single order  
system. It is much easier to design a type II compensator to  
stabilize the loop than to implement voltage mode control. Peak  
current mode control has an inherent input voltage feed-forward  
function to achieve good line regulation. Figure 40 shows the  
small signal model of the synchronous buck regulator.  
S
S
   
   
------------  
------------  
1 +  
1 +  
ˆ
GM R  
v
comp  
3
cz1  
cz2  
---------------- -------------------------------------------------------- --------------------------------------------------------------  
A S=  
=
v
ˆ
C + C   R + R   
S
S
v
   
6
7
2
3
FB  
-------------  
-------------  
S 1 +  
1 +  
   
cp1  
cp2  
(EQ. 8)  
Where  
C
+ C  
R + R  
2
1
1
6
7
3
--------------  
--------------  
----------------------  
----------------------  
=
,
=
   
=
   
cp2  
=
cz1  
cz2  
cp1  
R C  
R C  
R C C  
C R R  
3 2  
6
6
2
3
6
6
7
3
Compensator design goal:  
High DC gain  
Choose loop bandwidth f less than 100kHz  
c
^
^
L
R
^
P
LP  
I
I
v
L
IN  
o
Gain margin: >10dB  
Phase margin: >40°  
^
d
V
^
^
IN  
1:D  
d
V
IN  
I
L
Rc  
Co  
+
R
T
The compensator design procedure is as follows:  
Ro  
The loop gain at crossover frequency of f has a unity gain.  
c
Therefore, the compensator resistance R is determined by  
6
Equation 9.  
T (S)  
i
^
d
2f V C R  
o o t  
3
c
K
(EQ. 9)  
---------------------------------  
= 5.7610 f V C  
c o o  
R
=
6
GM V  
F
FB  
m
Where GM is the sum of the transconductance, g , of the voltage  
m
H (S)  
+
error amplifier in each phase. Compensator capacitor C is then  
e
6
T (S)  
V
given by Equation 10.  
^
V
COMP  
R C  
V C  
o o  
I R  
o 6  
R C  
-Av(S)  
o
o
1
c
o
(EQ. 10)  
-------------- --------------  
,C = max(--------------,---------------)  
7
C
=
=
6
R
R
f R  
6
6
s 6  
FIGURE 40. SMALL SIGNAL MODEL OF SYNCHRONOUS BUCK  
REGULATOR  
Put one compensator pole at zero frequency to achieve high DC  
gain, and put another compensator pole at either ESR zero  
frequency or half switching frequency, whichever is lower in  
Equation 10. An optional zero can boost the phase margin. CZ2  
Vo  
is a zero due to R and C .  
2
3
R
C
3
Put compensator zero 2 to 5 times f .  
c
2
V
1
FB  
(EQ. 11)  
---------------  
C =  
-
V
3
COMP  
f R  
c
2
R
3
GM  
V
REF  
+
Example: V = 5V, V = 1.8V, I = 8A, f = 1MHz, R = 200kΩ,  
IN sw  
O
O
2
R = 100kΩ, C = 4x22µF/3mΩ, L = 1µH, f = 100kHz, then  
3
o
c
R
6
compensator resistance R :  
C
6
7
3
C
(EQ. 12)  
6
R
= 5.7610 100kHz 1.8V 88F = 91.2k  
6
1.8V 88F  
8A 90.9k  
(EQ. 13)  
(EQ. 14)  
-------------------------------  
= 217pF  
C
C
=
6
7
FIGURE 41. TYPE II COMPENSATOR  
3m  88F  
1
= max(--------------------------------,-------------------------------------------------) = (2.9pF, 3.5pF)  
90.9k  1MHz90.9k  
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ISL8018  
It is also acceptable to use the closest standard values for C and  
PCB Layout Recommendation  
6
C . There is approximately 3pF parasitic capacitance from V  
7
COMP  
The PCB layout is a very important converter design step to make  
sure the designed converter works well. For ISL8018, the power  
loop is composed of the output inductor Ls, the output capacitor  
COUT, the PHASE’s pins and the PGND pin. It is necessary to make  
the power loop as small as possible and the connecting traces  
among them should be direct, short and wide. The switching  
node of the converter, the PHASE pins and the traces connected  
to the node are very noisy, so keep the voltage feedback trace  
away from these noisy traces. The input capacitor should be  
placed as close as possible to the VIN pin and the ground of the  
input and output capacitors should be connected as close as  
possible. The heat of the IC is mainly dissipated through the  
thermal pad. Maximizing the copper area connected to the  
thermal pad is preferable. In addition, a solid ground plane is  
helpful for better EMI performance. It is recommended to add at  
least 5 vias ground connection within the pad for the best  
thermal relief.  
to GND. Therefore, C is optional. Use C = 220pF and C = OPEN.  
7
6
7
1
(EQ. 15)  
-----------------------------------------------  
= 16pF  
C
=
3
100kHz 200k  
Use C = 15pF. Note that C may increase the loop bandwidth  
3
3
from previous estimated value. Figure 42 on page 19 shows the  
simulated voltage loop gain. It is shown that it has a 125kHz loop  
bandwidth with a 45° phase margin and 10dB gain margin. It  
may be more desirable to achieve an increased phase margin.  
This can be accomplished by lowering R by 20% to 30%.  
6
80  
60  
40  
20  
0
-20  
-40  
-60  
100  
1k  
10k  
100k  
1M  
FREQUENCY (Hz)  
150  
100  
50  
0
-50  
-100  
-150  
-200  
100  
1k  
10k  
100k  
1M  
FREQUENCY (Hz)  
FIGURE 42. SIMULATED LOOP GAIN  
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ISL8018  
Revision History  
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you  
have the latest Rev.  
DATE  
REVISION  
FN7889.0  
CHANGE  
September 30, 2015  
Initial Release.  
About Intersil  
Intersil Corporation is a leading provider of innovative power management and precision analog solutions. The company's products  
address some of the largest markets within the industrial and infrastructure, mobile computing and high-end consumer markets.  
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product  
information page found at www.intersil.com.  
You may report errors or suggestions for improving this datasheet by visiting www.intersil.com/ask.  
Reliability reports are also available from our website at www.intersil.com/support  
For additional products, see www.intersil.com/en/products.html  
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted  
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html  
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time  
without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be  
accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third  
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.  
For information regarding Intersil Corporation and its products, see www.intersil.com  
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ISL8018  
Package Outline Drawing  
L20.3x4  
20 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE  
Rev 1, 3/10  
0.10 M  
C
C
A
B
3.00  
A
M
0.05  
0.50  
16X  
20X 0.25 +0.05  
6
B
4
-0.07  
PIN 1 INDEX AREA  
(C 0.40)  
17  
20  
A
16  
1
6
PIN 1  
INDEX AREA  
4.00  
+0.10  
2.65  
-0.15  
11  
6
0.15  
(4X)  
A
10  
7
VIEW "A-A"  
1.65 +0.10  
-0.15  
TOP VIEW  
20x 0.40±0.10  
BOTTOM VIEW  
SEE DETAIL "X"  
C
C
0.10  
0.9± 0.10  
SEATING PLANE  
0.08  
C
SIDE VIEW  
(16 x 0.50)  
(2.65)  
(3.80)  
(20 x 0.25)  
5
0.2 REF  
C
(20 x 0.60)  
0.00 MIN.  
0.05 MAX.  
(1.65)  
(2.80)  
DETAIL "X"  
TYPICAL RECOMMENDED LAND PATTERN  
NOTES:  
1. Dimensions are in millimeters.  
Dimensions in ( ) for Reference Only.  
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.  
3. Unless otherwise specified, tolerance : Decimal ± 0.05  
4. Dimension applies to the metallized terminal and is measured  
between 0.15mm and 0.30mm from the terminal tip.  
Tiebar shown (if present) is a non-functional feature.  
5.  
6.  
The configuration of the pin #1 identifier is optional, but must be  
located within the zone indicated. The pin #1 indentifier may be  
either a mold or mark feature.  
FN7889.0  
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21  

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