ISL70001SRHF [INTERSIL]

Rad Hard and SEE Hard 6A Synchronous Buck Regulator; 抗辐射,并请参阅硬盘6A同步降压稳压器
ISL70001SRHF
型号: ISL70001SRHF
厂家: Intersil    Intersil
描述:

Rad Hard and SEE Hard 6A Synchronous Buck Regulator
抗辐射,并请参阅硬盘6A同步降压稳压器

稳压器
文件: 总17页 (文件大小:583K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
Rad Hard and SEE Hard 6A Synchronous Buck Regulator  
ISL70001SEH  
Features  
The ISL70001SEH is a radiation hardened and SEE hardened  
high efficiency monolithic synchronous buck regulator with  
integrated MOSFETs. This single chip power solution operates  
over an input voltage range of 3V to 5.5V and provides a tightly  
regulated output voltage that is externally adjustable from 0.8V  
to ~85% of the input voltage. Output load current capacity is 6A  
• ±1% Reference Voltage Over Line, Load, Temperature and  
Radiation  
• Current Mode Control for Excellent Dynamic Response  
• Full Mil-Temp Range Operation (T = -55°C to +125°C)  
A
• High Efficiency > 90%  
for T < +145°C.  
J
• Fixed 1MHz Operating Frequency  
• Operates from 3V to 5.5V Supply  
• Adjustable Output Voltage  
High integration and class leading radiation tolerance makes  
the ISL70001SEH an ideal choice to power many of today’s  
small form factor applications. Two devices can be  
- Two External Resistors Set V  
OUT  
• Bi-directional SYNC Pin Allows Two Devices to be Synchronized  
180° Out-of-Phase  
from 0.8V to ~85% of V  
IN  
synchronized to provide a complete power solution for large  
scale digital ICs, like field programmable gate arrays (FPGAs),  
that require separate core and I/O voltages.  
• Device Enable with Comparator Type Input  
• Power-Good Output Voltage Monitor  
• Adjustable Analog Soft-Start  
Applications  
• FPGA, CPLD, DSP, CPU Core or I/O Voltages  
• Low-Voltage, High-Density Distributed Power Systems  
• Input Undervoltage, Output Undervoltage and Output  
Overcurrent Protection  
Related Literature  
• ISL70001SRHEVAL1Z Evaluation Board, AN1518  
• Starts Into Pre-Biased Load  
• Electrically Screened to DLA SMD 5962-09225  
• QML Qualified per MIL-PRF-38535 Requirements  
Specifications for Rad Hard QML devices are controlled by the  
Defense Logistics Agency Land and Maritime (DLA). The SMD  
numbers listed in the Ordering Information table on page 2 must  
be used when ordering.  
• Radiation Hardness  
- Total Dose [50-300rad(Si)/s] . . . . . . . . . . .100krad(Si) min  
- Total Dose [<10mrad(Si)/s] . . . . . . . . . . . . .50krad(Si) min  
Detailed Electrical Specifications for these devices are contained  
in SMD 5962-09225. This link is also available on the  
ISL70001SEH device information page on the Intersil web site.  
• SEE Hardness  
- SEL and SEB LET . . . . . . . . . . . . 86.4MeV/mg/cm min  
2
-6  
eff  
2
2
- SEFI X-section (LET = 86.4MeV/mg/cm ) 1.4 x 10 cm  
eff  
max  
2
- SET LET (< 1 Pulse Perturbation) 86.4MeV/mg/cm min  
eff  
95  
90  
85  
80  
75  
70  
5V SUPPLY  
ISL70001SEH  
CORE  
AUX  
I/O  
SYNCH  
RAD TOLERANT  
FPGA  
RAD HARD LDO  
ISL70001SEH  
0
1
2
3
4
5
6
LOAD CURRENT (A)  
FIGURE 1. TYPICAL APPLICATION  
FIGURE 2. EFFICIENCY 5V INPUT TO 3.3V OUTPUT, T = +25°C  
A
November 30, 2011  
FN7956.0  
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.  
1-888-INTERSIL or 1-888-468-3774 |Copyright Intersil Americas Inc. 2011. 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
ISL70001SEH  
Functional Block Diagram  
POWER-ON  
RESET (POR)  
PORSEL  
PVINx  
CURRENT  
SENSE  
SLOPE  
COMPENSATION  
SOFT  
START  
SS  
PWM  
CONTROL  
LOGIC  
GATE  
DRIVE  
LXx  
EA  
GM  
FB  
COMPENSATION  
PGNDx  
UV  
POWER-GOOD  
PGOOD  
REF  
PWM  
REFERENCE  
0.6V  
TDI  
BIT  
TDO  
TRIM  
ZAP  
SYNC  
M/S  
Ordering Information  
PART NUMBER  
(Note 2)  
TEMP. RANGE  
(°C)  
ORDERING NUMBER  
5962R0922502VXC  
5962R0922502V9A  
ISL70001SRHF/PROTO  
ISL70001SRHX/SAMPLE  
ISL70001SRHEVAL1Z  
NOTES:  
PACKAGE  
ISL70001SEHVF (Note 1)  
ISL70001SEHVX  
-55 to +125  
-55 to +125  
-55 to +125  
-55 to +125  
48 Ld CQFP (Pb-Free)  
Die  
ISL70001SRHF/PROTO (Note 1)  
ISL70001SRHX/SAMPLE  
Evaluation Board  
48 Ld CQFP (Pb-Free)  
Die  
1. These Intersil Pb-free Hermetic packaged products employ 100% Au plate - e4 termination finish, which is RoHS compliant and compatible with both  
SnPb and Pb-free soldering operations.  
2. For Moisture Sensitivity Level (MSL), please see device information page for ISL70001SEH. For more information on MSL, please see Tech Brief  
TB363.  
FN7956.0  
November 30, 2011  
2
ISL70001SEH  
Pin Configuration  
ISL70001SEH  
(48 LD CQFP)  
TOP VIEW  
6
5
4
3
2
1
48 47 46 45 44 43  
42  
PVIN3  
LX3  
7
M/S  
ZAP  
TDI  
41  
40  
39  
38  
37  
8
PGND3  
PGND3  
PGND4  
PGND4  
LX4  
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
TDO  
PGOOD  
SS  
36  
35  
34  
33  
32  
31  
DVDD  
DVDD  
DGND  
DGND  
AGND  
AGND  
PVIN4  
PVIN4  
PVIN5  
PVIN5  
LX5  
19 20 21 22 23 24 25 26 27 28 29 30  
Pin Descriptions  
PIN NUMBER  
PIN NAME  
DESCRIPTION  
1, 2, 27, 28, 29, 30,  
37, 38, 39, 40, 47,  
48  
PGNDx  
These pins are the power grounds associated with the corresponding internal power blocks. Connect these pins  
directly to the ground plane. These pins should also connect to the negative terminals of the input and output  
capacitors. Locate the input and output capacitors as close as possible to the IC.  
3, 26, 31, 36, 41,  
46  
LXx  
These pins are the outputs of the corresponding internal power blocks and should be connected to the output  
filter inductor. Internally, these pins are connected to the synchronous MOSFET power switches. To minimize  
voltage undershoot, it is recommended that a Schottky diode be connected from these pins to PGNDx. The  
Schottky diode should be located as close as possible to the IC.  
4, 5, 24, 25, 32, 33,  
34, 35, 42, 43, 44,  
45  
PVINx  
SYNC  
These pins are the power supply inputs to the corresponding internal power blocks. These pins must be  
connected to a common power supply rail, which must fall in the range of 3V to 5.5V. Bypass these pins directly  
to PGNDx with ceramic capacitors located as close as possible to the IC.  
6
This pin is the synchronization I/O for the IC. When configured as an output (Master Mode), this pin drives the  
SYNC input of another ISL70001SEH. When configured as an input (Slave Mode), this pin accepts the SYNC  
output from another ISL70001SEH or an external clock. Synchronization of the slave unit is 180° out-of-phase  
with respect to the master unit. If synchronizing to an external clock, the clock must be SEE hardened and the  
frequency must be within the range of 1MHz ±20%.  
7
M/S  
This pin is the Master/Slave input for selecting the direction of the bi-directional SYNC pin. For SYNC = Output  
(Master Mode), connect this pin to DVDD. For SYNC = Input (Slave Mode), connect this pin to DGND.  
8
9
ZAP  
TDI  
This pin is a trim input and is used to adjust various internal circuitry. Connect this pin to DGND.  
This pin is the test data input of the internal BIT circuitry. Connect this pin to DGND.  
This pin is the test data output of the internal BIT circuitry. Connect this pin to DGND.  
10  
11  
TDO  
PGOOD  
This pin is the power-good output. This pin is an open drain logic output that is pulled to DGND when the output  
voltage is outside a ±11% typical regulation window. This pin can be pulled up to any voltage from 0V to 5.5V,  
independent of the supply voltage. A nominal 1kΩ to 10kΩ pull-up resistor is recommended. Bypass this pin  
to DGND with a 10nF ceramic capacitor to mitigate SEE.  
FN7956.0  
November 30, 2011  
3
ISL70001SEH  
Pin Descriptions(Continued)  
PIN NUMBER  
PIN NAME  
DESCRIPTION  
12  
SS  
This pin is the soft-start input. Connect a ceramic capacitor from this pin to DGND to set the soft-start output  
ramp time in accordance with Equation 1:  
t
= C V I  
REF SS  
(EQ. 1)  
SS  
SS  
where:  
t
C
= Soft-start output ramp time  
= Soft-start capacitor  
SS  
SS  
V
= Reference voltage (0.6V typical)  
REF  
I
= Soft-start charging current (23µA typical)  
SS  
Soft-start time is adjustable from approximately 2ms to 200ms.  
The range of the soft-start capacitor should be 82nF to 8.2µF, inclusive.  
13, 14  
DVDD  
These pins are the bias supply inputs to the internal digital control circuitry. Connect these pins together at the  
IC and locally filter them to DGND using a 1Ω resistor and a 1µF ceramic capacitor. Locate both filter  
components as close as possible to the IC.  
15, 16  
17, 18  
19  
DGND  
AGND  
AVDD  
REF  
These pins are the digital ground associated with the internal digital control circuitry. Connect these pins  
directly to the ground plane.  
These pins are the analog ground associated with the internal analog control circuitry. Connect these pins  
directly to the ground plane.  
This pin is the bias supply input to the internal analog control circuitry. Locally filter this pin to AGND using a 1Ω  
resistor and a 1µF ceramic capacitor. Locate both filter components as close as possible to the IC.  
20  
This pin is the internal reference voltage output. Bypass this pin to AGND with a 220nF ceramic capacitor  
located as close as possible to the IC. The bypass capacitor is needed to mitigate SEE. No current (sourcing or  
sinking) is available from this pin.  
21  
FB  
This pin is the voltage feedback input to the internal error amplifier. Connect a resistor from FB to VOUT and  
from FB to AGND to adjust the output voltage in accordance with Equation 2:  
V
= V  
⋅ [1 + (R R )]  
REF T B  
(EQ. 2)  
OUT  
where:  
= Output voltage  
V
OUT  
V
= Reference voltage (0.6V typical)  
REF  
R = Top divider resistor (Must be 1kΩ)  
T
R
= Bottom divider resistor  
B
The top divider resistor must be 1kΩ to mitigate SEE. Connect a 4.7nF ceramic capacitor across RT to mitigate SEE  
and to improve stability margins.  
22  
23  
EN  
This pin is the enable input to the IC. This is a comparator type input with a rising threshold of 0.6V and  
programmable hysteresis. Driving this pin above 0.6V enables the IC. Bypass this pin to AGND with a 10nF  
ceramic capacitor to mitigate SEE.  
PORSEL  
This pin is the input for selecting the rising and falling POR (Power-On-Reset) thresholds. For a nominal 5V  
supply, connect this pin to DVDD. For a nominal 3.3V supply, connect this pin to DGND. For nominal supply  
voltages between 5V and 3.3V, connect this pin to DGND.  
FN7956.0  
November 30, 2011  
4
ISL70001SEH  
Typical Application Schematic  
LX1  
LX2  
LX3  
LX4  
LX5  
LX6  
PVIN1  
PVIN2  
PVIN3  
PVIN4  
PVIN5  
PVIN6  
5V  
100µF  
1µF  
1µF  
1µH  
1.8V  
6A  
470µF  
20V  
3A  
1k  
1
AVDD  
FB  
1µF  
ISL70001SEH  
0V TO 5.5V  
499Ω  
AGND  
DVDD  
1
PGOOD  
10nF  
1µF  
VSENSE  
SYNC  
REF  
DGND  
EN  
220nF  
10nF  
M/S  
PORSEL  
TDI  
SS  
TDO  
ZAP  
100nF  
FIGURE 3. 5V INPUT SUPPLY VOLTAGE WITH MASTER MODE SYNCHRONIZATION  
FN7956.0  
November 30, 2011  
5
ISL70001SEH  
Typical Application Schematic(Continued)  
LX1  
LX2  
LX3  
LX4  
LX5  
LX6  
PVIN1  
PVIN2  
PVIN3  
PVIN4  
PVIN5  
PVIN6  
3.3V  
100µF  
1µF  
1µF  
1µH  
1.8V  
6A  
470µF  
20V  
3A  
4.7nF  
1kΩ  
1
DVDD  
FB  
1µF  
ISL70001SEH  
0V TO 5.5V  
499Ω  
DGND  
1
PGOOD  
AVDD  
10nF  
1µF  
VSENSE  
SYNC  
REF  
AGND  
EN  
220nF  
M/S  
10nF  
PORSEL  
TDI  
SS  
TDO  
ZAP  
100nF  
FIGURE 4. 3.3V INPUT SUPPLY VOLTAGE WITH SLAVE MODE SYNCHRONIZATION  
FN7956.0  
November 30, 2011  
6
ISL70001SEH  
Electrical Specifications Unless otherwise noted, VIN = AVDD = DVDD = PVINx = EN = M/S = 3V or 5.5V;  
GND = AGND = DGND = PGNDx = TDI = TDO = ZAP = 0V; FB = 0.65V; PORSEL = VIN for 4.5V VIN 5.5V and GND for V < 4.5V,  
IN  
SYNC = LXx = Open Circuit; PGOOD is pulled up to V with a 1k resistor; REF is bypassed to GND with a 220nF capacitor; SS is bypassed to GND with a  
IN  
100nF capacitor; I  
OUT  
= 0A; T = T = +25°C. (Note 3). Boldface limits apply over the operating temperature range, -55°C to +125°C; over a total iodizing  
A J  
dose of 100krad(Si) with exposure at a high dose rate of 50 - 300krad(Si)/s; and over a total iodizing dose of 50krad(Si) with exposure at a low dose rate  
of <10mrad(Si)/s.  
MIN  
MAX  
PARAMETER  
POWER SUPPLY  
TEST CONDITIONS  
(Note 4)  
TYP  
(Note 4)  
UNITS  
Operating Supply Current  
V
V
V
V
= 5.5V  
= 3.6V  
40  
25  
6
65  
45  
12  
6
mA  
mA  
mA  
mA  
IN  
IN  
IN  
IN  
Shutdown Supply Current  
= 5.5V, EN = GND  
= 3.6V, EN = GND  
3
OUTPUT VOLTAGE  
Reference Voltage Tolerance  
Output Voltage Tolerance  
0.594  
-2  
0.6  
0
0.606  
2
V
V
V
I
= 0.8V to 2.5V for V = 4.5V to 5.5V,  
IN  
%
OUT  
OUT  
OUT  
= 0.8V to 2.5V for V = 3V to 3.6V,  
IN  
= 0A to 6A (Notes 5, 6)  
Feedback (FB) Input Leakage Current  
PWM CONTROL LOGIC  
Oscillator Accuracy  
V
= 5.5V, V = 0.6V  
FB  
-1  
0
1
µA  
IN  
0.85  
.8  
1
1
1.15  
1.2  
MHz  
MHz  
ns  
ns  
ns  
ns  
V
External Oscillator Range  
Minimum LXx On Time  
V
V
V
V
= 5.5V, Test Mode  
= 5.5V, Test Mode  
= 3V, Test Mode  
= 3V, Test Mode  
110  
40  
150  
50  
1.3  
1.2  
0
150  
100  
210  
100  
IN  
IN  
IN  
IN  
Minimum LXx Off Time  
Minimum LXx On Time  
Minimum LXx Off Time  
Master/Slave (M/S) Input Voltage  
Input High Threshold  
Input Low Threshold  
V
- 0.5  
IN  
0.5  
1
V
Master/Slave (M/S) Input Leakage Current  
Synchronization (SYNC) Input Voltage  
V
= 5.5V, M/S = GND or V  
-1  
µA  
V
IN  
IN  
Input High Threshold, M/S = GND  
Input Low Threshold, M/S = GND  
2.3  
1.7  
1.5  
0
1
1
V
Synchronization (SYNC) Input Leakage  
Current  
V
= 5.5V, M/S = GND, SYNC = GND or V  
-1  
µA  
IN  
IN  
Synchronization (SYNC) Output Voltage  
V
V
- V @ I = -1mA  
IN OH OH  
0.15  
0.15  
0.4  
0.4  
V
V
@ I = 1mA  
OL OL  
POWER BLOCKS  
Upper Device r  
Lower Device r  
V
V
V
V
= 3V, 0.4A Per Power Block, Test Mode (Note 6)  
= 3V, 0.4A Per Power Block, Test Mode (Note 6)  
= 5.5V, EN = LXx = GND, Single LXx Output  
122  
77  
-1  
215  
146  
0
346  
236  
mΩ  
mΩ  
µA  
DS(ON)  
IN  
IN  
IN  
IN  
DS(ON)  
LXx Output Leakage  
= 5.5V, EN = GND, LXx = V , Single LXx Output  
IN  
0
15  
µA  
Deadtime  
Efficiency  
Within a Single Power Block or between Power  
Blocks (Note 6)  
1.7  
5
ns  
V
V
= 3.3V, V  
OUT  
= 1.8V, I  
= 3A  
90  
92  
%
%
IN  
IN  
OUT  
= 5V, V  
OUT  
= 2.5V, I  
OUT  
= 3A  
FN7956.0  
November 30, 2011  
7
ISL70001SEH  
Electrical Specifications Unless otherwise noted, VIN = AVDD = DVDD = PVINx = EN = M/S = 3V or 5.5V;  
GND = AGND = DGND = PGNDx = TDI = TDO = ZAP = 0V; FB = 0.65V; PORSEL = VIN for 4.5V VIN 5.5V and GND for V < 4.5V,  
IN  
SYNC = LXx = Open Circuit; PGOOD is pulled up to V with a 1k resistor; REF is bypassed to GND with a 220nF capacitor; SS is bypassed to GND with a  
IN  
100nF capacitor; I  
OUT  
= 0A; T = T = +25°C. (Note 3). Boldface limits apply over the operating temperature range, -55°C to +125°C; over a total iodizing  
A J  
dose of 100krad(Si) with exposure at a high dose rate of 50 - 300krad(Si)/s; and over a total iodizing dose of 50krad(Si) with exposure at a low dose rate  
of <10mrad(Si)/s. (Continued)  
MIN  
MAX  
PARAMETER  
POWER-ON RESET  
TEST CONDITIONS  
(Note 4)  
TYP  
(Note 4)  
UNITS  
POR Select (PORSEL)  
Input High Threshold  
Input Low Threshold  
= 5.5V, PORSEL = GND or V  
V
- 0.5  
1.4  
1.2  
0
V
V
IN  
0.5  
1
POR Select (PORSEL) Input Leakage  
Current  
V
-1  
µA  
IN  
IN  
VIN POR  
Rising Threshold, PORSEL = V  
4.1  
225  
2.65  
90  
4.25  
325  
2.8  
175  
0.6  
0
4.45  
425  
2.95  
260  
0.64  
3
V
mV  
V
IN  
Hysteresis, PORSEL = V  
IN  
Rising Threshold, PORSEL = GND  
Hysteresis, PORSEL = GND  
Rising/Falling Threshold  
mV  
V
Enable (EN) Input Voltage  
Enable (EN) Input Leakage Current  
Enable (EN) Sink Current  
SOFT-START  
0.56  
-3  
V
= 5.5V, EN = GND or V  
µA  
µA  
IN  
IN  
EN = 0.3V  
6.4  
11  
16.6  
Soft-Start Source Current  
Soft-Start Discharge ON-Resistance  
Soft-Start Discharge Time  
POWER-GOOD SIGNAL  
Rising Threshold  
SS = GND  
20  
23  
2.2  
256  
27  
µA  
Ω
4.7  
Clock Cycles  
V
V
V
V
V
V
as a % of V , Test Mode  
REF  
107  
2
111  
3.5  
115  
5
%
%
FB  
FB  
FB  
FB  
IN  
Rising Hysteresis  
as a % of V , Test Mode  
REF  
Falling Threshold  
as a % of V , Test Mode  
REF  
85  
2
89  
93  
5
%
Falling Hysteresis  
as a % of V , Test Mode  
REF  
3.5  
%
Power-Good Drive  
= 3V, PGOOD = 0.4V, EN = GND  
= PGOOD = 5.5V  
7.3  
8.2  
mA  
µA  
Power-Good Leakage  
0.001  
1
IN  
PROTECTION FEATURES  
Undervoltage Monitor  
Undervoltage Trip Threshold  
Undervoltage Recovery Threshold  
Overcurrent Monitor  
V
V
= 3V, V as a % of V , Test mode  
FB REF  
71  
84  
75  
88  
79  
92  
%
%
IN  
= 3V, V as a % of V , Test mode  
FB REF  
IN  
Overcurrent Trip Level  
LX4 Power Block, Test Mode, (Note 7)  
= 3V, SS interval = 200µs, Test Mode, Fault  
1.3  
1.9  
0.8  
2.5  
5
A
Overcurrent or Short-Circuit Duty-Cycle  
V
%
IN  
interval divided by hiccup interval  
NOTES:  
3. Typical values shown are not guaranteed. Guaranteed min/max values are provided in the SMD.  
4. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.  
5. Limits do not include tolerance of external feedback resistors. The 0A to 6A output current range may be reduced by Minimum LXx On Time and  
Minimum LXx Off Time specifications.  
6. Limits established by characterization or analysis and are not production tested.  
7. During an output short-circuit, peak current through the power block(s) can continue to build beyond the overcurrent trip level by up to 3A. With all six  
power blocks connected, peak current through the power blocks and output inductor could reach (6 x 2.5A) + 3A = 18A. The output inductor must  
support this peak current without saturating.  
FN7956.0  
November 30, 2011  
8
ISL70001SEH  
output current. See the “Typical Application Schematic” on  
page 5 for pin connection guidance.  
Functional Description  
The ISL70001SEH is a monolithic, fixed frequency, current-mode  
synchronous buck regulator with user configurable power blocks.  
Two ISL70001SEH devices can be used to provide a total DC/DC  
solution for FPGAs, CPLDs, DSPs and CPUs.  
A scaled pilot device associated with each power block provides  
current feedback. Power block 4 contains the master pilot device  
and this is why it must be connected to the output inductor.  
The ISL70001SEH utilizes peak current-mode control with  
integrated compensation and switches at a fixed frequency of  
1MHz. Two ISL70001SEH devices can be synchronized 180°  
out-of-phase to reduce input RMS ripple current. These attributes  
reduce the number and size of external components required,  
while providing excellent output transient response. The  
internal synchronous power switches are optimized for high  
efficiency and good thermal performance.  
Main Control Loop  
During normal operation, the internal top power switch is turned  
on at the beginning of each clock cycle. Current in the output  
inductor ramps up until the current comparator trips and turns  
off the top power MOSFET. The bottom power MOSFET turns on  
and the inductor current ramps down for the rest of the cycle.  
The current comparator compares the output current at the  
ripple current peak to a current pilot. The error amplifier monitors  
The chip features a comparator type enable input that provides  
flexibility. It can be used for simple digital on/off control or,  
alternately, can provide undervoltage lockout capability by  
using two external resistors to precisely sense the level of an  
external supply voltage. A power-good signal indicates when the  
output voltage is within ±11% typical of the nominal output  
voltage.  
V
and compares it with an internal reference voltage. The  
OUT  
output voltage of the error amplifier drives a proportional current  
to the pilot. If V is low, the current level of the pilot is  
OUT  
increased and the trip off current level of the output is increased.  
The increased output current raises V  
with the reference voltage.  
until it is in agreement  
OUT  
Output Voltage Selection  
The output voltage of the ISL70001SEH can be adjusted using an  
external resistor divider as shown in Figure 6.  
Regulator start-up is controlled by an analog soft-start circuit,  
which can be adjusted from approximately 2ms to 200ms by  
using an external capacitor.  
The ISL70001SEH incorporates fault protection for the  
regulator. The protection circuits include input undervoltage,  
output undervoltage, and output overcurrent.  
V
= 0.6V  
= 220nF  
= 1k  
= 4.7nF  
REF  
REF  
T
C
L
OUT  
C
R
C
V
OUT  
LXx  
Power Blocks  
C
OUT  
The power output stage of the regulator consists of six 1A  
capable power blocks that are paralleled to provide full 6A  
output current capability. The block diagram in Figure 5 shows a  
top level view of the individual power blocks.  
C
R
C
T
ERROR  
AMPLIFIER  
FB  
-
V
REF  
REF  
R
B
+
C
REF  
PVIN1  
LX1  
PGND1  
PVIN6  
LX6  
PGND6  
POWER BLOCK 1  
POWER BLOCK 2  
POWER BLOCK 3  
POWER BLOCK 6  
POWER BLOCK 5  
POWER BLOCK 4  
FIGURE 6. OUTPUT VOLTAGE SELECTION  
R should be selected as 1kΩ to mitigate SEE. R should be  
shunted by a 4.7nF ceramic capacitor, C , to mitigate SEE and to  
improve loop stability margins. The REF pin should be bypassed  
to AGND with a 220nF ceramic capacitor to mitigate SEE. It  
should be noted that no current (sourcing or sinking) is available  
from the REF pin. R can be determined from Equation 3. The  
designer can configure the output voltage from 0.8V to 85% of  
the input voltage.  
PVIN2  
LX2  
PGND2  
T
T
PVIN5  
LX5  
PGND5  
C
PVIN3  
LX3  
PGND3  
PVIN4  
LX4  
PGND4  
B
V
(EQ. 3)  
FIGURE 5. POWER BLOCK DIAGRAM  
REF  
V  
REF  
-------------------------------  
= R ⋅  
T
R
B
V
OUT  
Each power block has a power supply input pin, PVINx, a phase  
output pin, LXx, and a power supply ground pin, PGNDx. All PVINx  
pins must be connected to a common power supply rail and all  
PGNDx pins must be connected to a common ground. LXx pins  
should be connected to the output inductor based on the  
required load current, but must include the LX4 pin. For example,  
if 3A of output current is needed, any three LXx pins can be  
connected to the inductor as long as one of them is the LX4 pin.  
The unused LXx pins should be left unconnected. Connecting all  
six LXx pins to the output inductor provides a maximum 6A of  
Switching Frequency/Synchronization  
The ISL70001SEH features an internal oscillator running at a  
fixed frequency of 1MHz ±15% over recommended operating  
conditions. The regulator can be configured to run from the  
internal oscillator or can be synchronized to another  
ISL70001SEH or an SEE hardened external clock with a  
frequency range of 1MHz ±20%.  
FN7956.0  
November 30, 2011  
9
ISL70001SEH  
To run the regulator from the internal oscillator, connect the M/S  
pin to DVDD. In this case, the output of the internal oscillator  
appears on the SYNC pin. To synchronize the regulator to the  
SYNC output of another ISL70001SEH regulator or to an SEE  
hardened external clock, connect the M/S pin to DGND. In this  
case, the SYNC pin is an input that accepts an external  
V
I
C
= 0.6V  
= 11µA  
R
EN  
V
IN1  
= 10nF  
EN  
PVINx  
synchronizing signal. When synchronizing multiple devices, Slave  
regulators are synchronized 180° out-of-phase with respect to  
the SYNC output of a Master regulator or to an external clock.  
V
IN2  
ENABLE  
COMPARATOR  
R1  
R2  
Operation Initialization  
EN  
+
The ISL70001SEH initializes based on the state of the power-on  
reset (POR) monitor of the PVINx inputs and the state of the EN  
input. Successful initialization prompts a soft-start interval, and  
the regulator begins slowly ramping the output voltage. Once the  
commanded output voltage is within the proper window of  
operation, the power-good signal changes state from low to high,  
indicating proper regulator operation.  
C
V
R
EN  
-
POR  
LOGIC  
I
EN  
FIGURE 7. ENABLE CIRCUIT  
Power-On Reset  
The POR circuitry prevents the controller from attempting to  
soft-start before sufficient bias is present at the PVINx pins.  
With the part enabled and the I current sink off, the disable  
EN  
level is set by the resistor divider. The disable level is defined by  
Equation 5.  
The POR threshold of the PVINx pins is controlled by the PORSEL  
pin. For a nominal 5V supply voltage, PORSEL should be  
connected to DVDD. For a nominal 3.3V supply voltage, PORSEL  
should be connected to DGND. For nominal supply voltages  
between 5V and 3.3V, PORSEL should be connected to DGND.  
The POR rising and falling thresholds are shown in the “Electrical  
Specifications” table on page 8.  
R1  
R2  
(EQ. 5)  
-------  
= V 1 +  
R
V
DISABLE  
The difference between the enable and disable levels provides  
adjustable hysteresis so that noise on V does not interfere  
IN2  
with the enabling or disabling of the regulator.  
To mitigate SEE, the EN pin should be bypassed to the AGND pin  
with a 10nF ceramic capacitor.  
Hysteresis between the rising and falling thresholds ensures that  
small perturbations on PVINx seen during turn-on/turn-off of the  
regulator do not cause inadvertent turn-off/turn-on of the  
regulator. When the PVINx pins are below the POR rising  
threshold, the internal synchronous power MOSFET switches are  
turned off, and the LXx pins are held in a high-impedance state.  
Soft-Start  
Once the POR and enable circuits are satisfied, the regulator  
initiates a soft-start. Figure 8 shows that the soft-start circuit  
clamps the error amplifier reference voltage to the voltage on an  
external soft-start capacitor connected to the SS pin.  
Enable and Disable  
After the POR input requirement is met, the ISL70001SEH  
remains in shutdown until the voltage at the enable input rises  
above the enable threshold. As shown in Figure 7, the enable  
circuit features a comparator type input. In addition to simple  
logic on/off control, the enable circuit allows the level of an  
external voltage to precisely gate the turn-on/turn-off of the  
V
I
R
= 0.6V  
= 23µA  
= 2.2Ω  
REF  
SS  
V
OUT  
D
R
T
FB  
regulator. An internal I current sink with a typical value of  
11µA is only active when the voltage on the EN pin is below the  
R
EN  
B
ERROR  
AMPLIFIER  
SS  
enable threshold. The current sink pulls the EN pin low. As V  
IN2  
rises, the enable level is not set exclusively by the resistor divider  
from V  
-
C
SS  
+
+
REF  
.
IN2  
V
REF  
PWM  
LOGIC  
C
R
REF  
D
With the current sink active, the enable level is defined by  
I
SS  
Equation 4. R1 is the resistor from the EN pin to V  
the resistor from the EN pin to the AGND pin.  
and R2 is  
IN2  
R1  
R2  
-------  
+ I R1  
EN  
V
= V  
1 +  
(EQ. 4)  
ENABLE  
R
Once the voltage at the EN pin reaches the enable threshold, the  
current sink turns off.  
I
EN  
FIGURE 8. SOFT-START CIRCUIT  
FN7956.0  
November 30, 2011  
10  
ISL70001SEH  
The soft-start capacitor is charged by an internal I current  
is a fixed percentage of the reference voltage. Once the  
SS  
source. As the soft-start capacitor is charged, the output voltage  
comparator trips, indicating a valid undervoltage condition, a  
3-bit undervoltage counter increments. The counter is reset if the  
feedback voltage rises back above the undervoltage threshold,  
plus a specified amount of hysteresis outlined in the “Electrical  
Specifications” table on page 8. If the 3-bit counter overflows, the  
undervoltage protection logic shuts down the regulator.  
slowly ramps to the set point determined by the reference  
voltage and the feedback network. Once the voltage on the SS  
pin is equal to the internal reference voltage, the soft-start  
interval is complete. The controlled ramp of the output voltage  
reduces the inrush current during start-up. The soft-start output  
ramp interval is defined in Equation 6 and is adjustable from  
approximately 2ms to 200ms. The value of the soft-start  
After the regulator shuts down, it enters a delay interval  
equivalent to the soft-start interval, which allows the device to  
cool. The undervoltage counter is reset when the device enters  
the delay interval. The protection logic initiates a normal  
soft-start once the delay interval ends. If the output successfully  
soft-starts, the power-good signal goes high, and normal  
operation continues. If undervoltage conditions continue to exist  
during the soft-start interval, the undervoltage counter must  
overflow before the regulator shuts down again. This hiccup  
mode continues indefinitely until the output soft-starts  
successfully.  
capacitor, C , should range from 8.2nF to 8.2µF, inclusive. The  
SS  
peak inrush current can be computed from Equation 7. The soft-  
start interval should be long enough to ensure that the peak  
inrush current plus the peak output load current does not exceed  
the overcurrent trip level of the regulator.  
V
REF  
------------  
t
= C  
(EQ. 6)  
SS  
SS  
I
SS  
V
OUT  
------------  
I
= C  
(EQ. 7)  
INRUSH  
OUT  
t
SS  
Overcurrent Protection  
The soft-start capacitor is immediately discharged by a 2.2Ω  
resistor whenever POR conditions are not met or EN is pulled low.  
The soft-start discharge time is equal to 256 clock cycles.  
A pilot device integrated into the PMOS transistor of Power Block 4  
samples current each cycle. This current feedback is scaled and  
compared to an overcurrent threshold based on the number of  
power blocks connected. Each additional power block connected  
beyond Power Block 4 increases the overcurrent limit by 2A. For  
example, if three power blocks are connected, the typical current  
limit threshold would be 3 x 2A = 6A.  
Power-Good  
The power-good (PGOOD) pin is an open-drain logic output that  
indicates when the output voltage of the regulator is within  
regulation limits. The power-good pin pulls low during shutdown  
and remains low when the controller is enabled. After a  
successful soft-start, the PGOOD pin releases, and the voltage  
rises with an external pull-up resistor. The power-good signal  
transitions low immediately when the EN pin is pulled low.  
If the sampled current exceeds the overcurrent threshold, a 3-bit  
overcurrent counter increments by one LSB. If the sampled current  
falls below the threshold before the counter overflows, the counter  
is reset. Once the overcurrent counter reaches 111, the regulator  
shuts down.  
The power-good circuitry monitors the FB pin and compares it to  
the rising and falling thresholds shown in the “Electrical  
Specifications” table on page 8. If the feedback voltage exceeds  
the typical rising limit of 111% of the reference voltage, the  
PGOOD pin pulls low. The PGOOD pin continues to pull low until  
the feedback voltage falls to a typical of 107.5% of the reference  
voltage. If the feedback voltage drops below a typical of 89% of  
the reference voltage, the PGOOD pin pulls low. The PGOOD pin  
continues to pull low until the feedback voltage rises to a typical  
92.5% of the reference voltage. The PGOOD pin then releases  
and signals the return of the output voltage to within the  
power-good window.  
After the regulator shuts down, it enters a delay interval,  
equivalent to the soft-start interval, which allows the device to  
cool. The overcurrent counter is reset when the device enters the  
delay interval. The protection logic initiates a normal soft-start  
once the delay interval ends. If the output successfully  
soft-starts, the power-good signal goes high, and normal  
operation continues. If overcurrent conditions continue to exist  
during the soft-start interval, the overcurrent counter must  
overflow before the regulator shut downs the output again. This  
hiccup mode continues indefinitely until the output soft-starts  
successfully.  
The PGOOD pin can be pulled up to any voltage from 0V to 5.5V,  
independently from the supply voltage. The pull-up resistor  
should have a nominal value from 1kΩ to 10kΩ. The PGOOD pin  
should be bypassed to DGND, with a 10nF ceramic capacitor to  
mitigate SEE.  
Note: To prevent severe negative ringing that can disturb the  
overcurrent counter, it is recommended that a Schottky diode of  
appropriate rating be added from the LXx pins to the PGNDx pins.  
Feedback Loop Compensation  
To reduce the number of external components and to simplify the  
process of determining compensation components, the  
ISL70001SEH PWM controller has an internally compensated  
error amplifier.  
Fault Monitoring and Protection  
The ISL70001SEH actively monitors output voltage and current  
to detect fault conditions. Fault conditions trigger protective  
measures to prevent damage to the regulator and external load  
device.  
Due to the current loop feedback in peak current mode control, the  
modulator has a single pole response with -20dB slope at a  
frequency determined by the load (Equation 8):  
1
Undervoltage Protection  
A hysteretic comparator monitors the FB pin of the regulator. The  
feedback voltage is compared to an undervoltage threshold that  
------------------------------------  
=
F
(EQ. 8)  
PO  
2π ⋅ R C  
O
OUT  
FN7956.0  
November 30, 2011  
11  
ISL70001SEH  
where R is load resistance and C  
OUT  
capacitance. For this type of modulator, a Type 2 compensation  
circuit is usually sufficient.  
is the output load  
Output Filter Design  
O
The output inductor and the output capacitor bank together form  
a low-pass filter responsible for smoothing the pulsating voltage  
at the phase node. The filter must also provide the transient  
energy until the regulator can respond. Since the filter has low  
bandwidth relative to the switching frequency, it limits the  
system transient response. The output capacitors must supply or  
sink current while the current in the output inductor increases or  
decreases to meet the load demand.  
Figure 9 shows a Type 2 amplifier and its response, along with  
the responses of the current mode modulator and the converter.  
C2  
C1  
R2  
CONVERTER  
R1  
EA  
OUTPUT CAPACITOR SELECTION  
TYPE 2 EA  
The critical load parameters in choosing the output capacitors are  
the maximum size of the load step (ΔI  
), the load-current slew  
STEP  
rate (di/dt), and the maximum allowable output voltage deviation  
G
= 25.1dB  
EA  
MODULATOR  
under transient loading (ΔV ). Capacitors are characterized  
MAX  
F
F
P
Z
according to their capacitance, ESR (Equivalent Series Resistance)  
and ESL (Equivalent Series Inductance).  
F
PO  
F
C
At the beginning of a load transient, the output capacitors supply all  
of the transient current. The output voltage initially deviates by an  
amount approximated by the voltage drop across the ESL. As the  
load current increases, the voltage drop across the ESR increases  
linearly until the load current reaches its final value. Neglecting the  
contribution of inductor current and regulator response, the output  
voltage initially deviates by an amount shown in Equation 11.  
FIGURE 9. FEEDBACK LOOP COMPENSATION  
The Type 2 amplifier, in addition to the pole at origin, has a  
zero-pole pair that causes a flat gain region at frequencies  
between the zero and the pole (Equations 9 and 10).  
1
di  
-----  
ΔV  
ESL ×  
+ [ESR × ΔI  
]
STEP  
(EQ. 11)  
MAX  
-----------------------------  
F
=
= 8.6kHz  
dt  
Z
(EQ. 9)  
2π ⋅ R C  
2
1
The filter capacitors selected must have sufficiently low ESL and  
ESR such that the total output voltage deviation is less than the  
maximum allowable ripple.  
1
-----------------------------  
2π ⋅ R C  
F
=
= 546kHz  
(EQ. 10)  
P
1
2
Most capacitor solutions rely on a mixture of high frequency  
capacitors with relatively low capacitance in combination with  
bulk capacitors having high capacitance but larger ESR.  
Minimizing the ESL of the high-frequency capacitors allows them  
to support the output voltage as the current increases.  
Minimizing the ESR of the bulk capacitors allows them to supply  
the increased current with less output voltage deviation.  
Zero frequency and amplifier high-frequency gain were chosen to  
satisfy typical applications. The crossover frequency will appear  
at the point where the modulator attenuation equals the  
amplifier high frequency gain. The only task that the system  
designer has to complete is to specify the output filter capacitors  
to position the load main pole somewhere within one decade  
lower than the amplifier zero frequency. Equation 13 on page 12  
approximates the amount of capacitance needed to achieve an  
optimal pole location depending on the number of LXx pins  
connected. With this type of compensation, plenty of phase  
margin is easily achieved due to zero-pole pair phase ‘boost’.  
Ceramic capacitors with X7R dielectric are recommended.  
Alternately, a combination of low ESR solid tantalum capacitors  
and ceramic capacitors with X7R dielectric may be used.  
The ESR of the bulk capacitors is responsible for most of the  
output voltage ripple. As the bulk capacitors sink and source the  
Conditional stability may occur only when the main load pole is  
positioned too much to the left side on the frequency axis due to  
excessive output filter capacitance. In this case, the ESR zero  
placed within the 1.2kHz to 30kHz range gives some additional  
phase ‘boost’. Some phase boost is also be achieved by  
inductor AC ripple current, a voltage, V  
, develops across  
P-P(MAX)  
the bulk capacitor according to Equation 12.  
(V V  
)V  
OUT OUT  
IN  
----------------------------------------------  
= ESR ×  
V
(EQ. 12)  
P-P(MAX)  
L
× f × V  
s IN  
OUT  
connecting the recommended capacitor C in parallel with the  
C
upper resistor R of the divider that sets the output voltage value,  
as demonstrated in Figure 6.  
T
Another consideration in selecting the output capacitors is loop  
stability. The total output capacitance sets the dominant pole of  
the PWM. Because the ISL70001SEH uses integrated  
compensation techniques, it is necessary to restrict the output  
capacitance in order to optimize loop stability. The  
recommended load capacitance can be estimated using  
Equation 13.  
Component Selection Guide  
This design guide is intended to provide a high-level explanation  
of the steps necessary to create a power converter. It is assumed  
the reader is familiar with many of the basic skills and  
techniques referenced below. In addition to this guide, Intersil  
provides a complete evaluation board that includes schematic,  
BOM, and an example PCB layout (see Ordering Information  
table on page 2).  
1.8V  
------------  
C
= 75μF × NumberofLXxPinsConnected ×  
OUT  
V
OUT  
(EQ. 13)  
FN7956.0  
November 30, 2011  
12  
ISL70001SEH  
Another stability requirement on the selection of the output  
capacitor is that the ‘ESR zero’ (f ) be placed at 60kHz to  
90kHz. This range is set by an internal, single compensation zero  
at 8.6kHz. This ESR zero location contributes to increased phase  
margin of the control loop; therefore (Equation 14):  
Input Capacitor Selection  
ZESR  
Input capacitors are responsible for sourcing the AC component  
of the input current flowing into the switching power devices.  
Their RMS current capacity must be sufficient to handle the AC  
component of the current drawn by the switching power devices,  
which is related to duty cycle. The maximum RMS current  
required by the regulator is closely approximated by Equation 19.  
1
----------------------------------------------  
ESR =  
(EQ. 14)  
2π(f  
)(C  
)
OUT  
ZESR  
2
V
V
V  
V
2
OUT  
1
12  
IN  
OUT  
OUT  
-----------------  
------  
--------------------------------- -----------------  
I
=
×
I
+
×
×
In conclusion, the output capacitors must meet three criteria:  
RMS  
OUT  
V
V
L
× f  
MAX  
MAX  
IN  
IN  
OUT  
s
1. They must have sufficient bulk capacitance to sustain the  
output voltage during a load transient while the output  
inductor current is slewing to the value of the load transient.  
(EQ. 19)  
The important parameters to consider when selecting an input  
capacitor are the voltage rating and the RMS ripple current  
rating. For reliable operation, select capacitors with voltage  
ratings at least 1.5x greater than the maximum input voltage.  
The capacitor RMS ripple current rating should be higher than  
the largest RMS ripple current required by the circuit.  
2. The ESR must be sufficiently low to meet the desired output  
voltage ripple due to the output inductor current.  
3. The ESR zero should be placed, in a rather large range, to  
provide additional phase margin.  
Ceramic capacitors with X7R dielectric are recommended.  
Alternately, a combination of low ESR solid tantalum capacitors  
and ceramic capacitors with X7R dielectric may be used. The  
ISL70001SEH requires a minimum effective input capacitance of  
100µF for stable operation.  
OUTPUT INDUCTOR SELECTION  
Once the output capacitors are selected, the maximum allowable  
ripple voltage, V  
, determines the lower limit on the  
inductance as shown in Equation 15.  
P-P(MAX)  
(V V  
)V  
OUT OUT  
IN  
-------------------------------------------------  
L
ESR ×  
(EQ. 15)  
OUT  
Derating Current Capability  
f × V × V  
P-P(MAX)  
s
IN  
Most space programs issue specific derating guidelines for parts,  
but these guidelines take the pedigree of the part into account.  
For instance, a device built to MIL-PRF-38535, such as the  
ISL70001, is already heavily derated from a current density  
standpoint. However, a mil-temp or commercial IC that is  
up-screened for use in space applications may need additional  
current derating to ensure reliable operation because it was not  
built to the same standards as the ISL70001.  
Since the output capacitors are supplying a decreasing portion of  
the load current while the regulator recovers from the transient,  
the capacitor voltage becomes slightly depleted. The output  
inductor must be capable of assuming the entire load current  
before the output voltage decreases more than ΔV  
. This  
MAX  
places an upper limit on inductance.  
Equation 16 gives the upper limit on output inductance for the  
case when the trailing edge of the current transient causes a  
greater output voltage deviation than the leading edge.  
Equation 17 addresses the leading edge. Normally, the trailing  
edge dictates the inductance selection because duty cycles are  
usually <50%. Nevertheless, both inequalities should be  
evaluated, and inductance should be governed based on the  
Figure 10 shows the maximum average output current of the  
ISL70001 with respect to junction temperature. These plots take  
into account the worst-case current share mismatch in the power  
blocks and the current density requirement of MIL-PRF-38535  
2
(< 2 x 105 A/cm ). The plot clearly shows that the ISL70001 can  
handle 12.1A at +125°C from a worst-case current density  
standpoint, but the part is limited to 7.8A because that is the  
lower limit of the current limit threshold with all six power blocks  
connected.  
lower of the two results. In each equation, L  
is the output  
OUT  
inductance, C  
OUT  
is the total output capacitance, and ΔI is  
L(P-P)  
the peak-to-peak ripple current in the output inductor.  
2 C  
V  
OUT  
OUT  
(EQ. 16)  
13  
L
L
--------------------------------------- ΔV  
I ESR)  
L(P-P)  
OUT  
MAX  
2
I  
)
12.14  
STEP  
12  
11  
2 C  
10.18  
OUT  
10  
MINIMUM OCP  
-------------------------- ΔV  
I  
ESR)  
V
V  
IN OUT  
(EQ. 17)  
OUT  
MAX  
L(P-P)  
2
I  
)
LEVEL = 7.8A  
9
8
7
6
5
4
STEP  
8.57  
The other concern when selecting an output inductor is to ensure  
there is adequate slope compensation when the regulator is  
operated above 50% duty cycle. Since the internal slope  
compensation is fixed, output inductance should satisfy  
Equation 18 to ensure this requirement is met.  
7.25  
6.16  
6A @ +146°C  
5.3  
120  
125  
130  
135  
140  
145  
150  
155  
4.32μH  
JUNCTION TEMPERATURE (°C)  
(EQ. 18)  
-----------------------------------------------------------------------------------  
L
OUT  
NumberofLXxPinsConnected  
FIGURE 10. CURRENT vs TEMPERATURE  
FN7956.0  
November 30, 2011  
13  
ISL70001SEH  
PCB Design  
L
V
OUT  
OUT  
LXx  
3A  
PCB design is critical to high-frequency switching regulator  
performance. Careful component placement and trace routing  
are necessary to reduce voltage spikes and minimize  
undesirable voltage drops. Selection of a suitable thermal  
interface material is also required for optimum heat dissipation  
and to provide lead strain relief. See Table 1 on page 16 for  
layout x-y coordinates.  
C
OUT  
R
C
S
S
R
C
C
T
PGNDx  
FB  
ERROR  
AMPLIFIER  
-
PCB Plane Allocation  
V
R
REF  
REF  
B
+
Four layers of 2-ounce copper are recommended. Layer 2 should  
be a dedicated ground plane with all critical component ground  
connections made with vias to this layer. Layer 3 should be a  
dedicated power plane split between the input and output power  
rails. Layers 1 and 4 should be used primarily for signals but can  
also provide additional power and ground islands, as required.  
C
REF  
FIGURE 11. SCHOTTKY DIODE AND R-C SNUBBER  
PCB Layout  
Use a small island of copper to connect the LXx pins of the IC to  
the output inductor on Layers 1 and 4. To minimize capacitive  
coupling to the power and ground planes, void the copper on  
Layers 2 and 3 adjacent to the island. Place most of the island of  
Layer 4 to minimize the amount of copper that must be voided  
from the ground plane (Layer 2).  
PCB Component Placement  
Components should be placed as close as possible to the IC to  
minimize stray inductance and resistance. Prioritize the  
placement of bypass capacitors on the pins of the IC in the order  
shown: REF, SS, AVDD, DVDD, PVINx (high frequency capacitors),  
EN, PGOOD, PVINx (bulk capacitors).  
Keep all other signal traces as short as possible.  
For an example layout, see AN1518.  
Locate the output voltage resistive divider as close as possible to  
the FB pin of the IC. The top leg of the divider should connect  
directly to the POL (Point of Load), and the bottom leg of the  
divider should connect directly to AGND. The junction of the  
resistive divider should connect directly to the FB pin.  
Thermal Management  
For optimum thermal performance, place a pattern of vias on the  
top layer of the PCB directly underneath the IC. Connect the vias  
to the ground plane on Layer 2, which serves as a heat sink. To  
ensure good thermal contact, thermal interface material such as  
a Sil-Pad or thermally conductive epoxy should be used to fill the  
gap between the vias and the bottom of the IC.  
Locate a Schottky clamp diode as close as possible to the LXx  
and PGNDx pins of the IC. A small series R-C snubber connected  
from the LXx pins to the PGNDx pins may be used to damp high  
frequency ringing on the LXx pins, if desired, see Figure 11.  
Lead Strain Relief  
For strain relief, a Sil-Pad or a thin layer of thermally conductive  
epoxy can be used to raise the bottom of the IC from the PCB  
surface so that a slight bend can be added to the leads of the IC.  
FN7956.0  
November 30, 2011  
14  
ISL70001SEH  
BACKSIDE FINISH  
Die Characteristics  
Die Dimensions  
Silicon  
ASSEMBLY RELATED INFORMATION  
5720µm x 5830µm (225.2 mils x 229.5 mils)  
Thickness: 483µm ± 25.4µm (19.0 mils ± 1 mil)  
Substrate Potential  
PGND  
Interface Materials  
ADDITIONAL INFORMATION  
Worst Case Current Density  
GLASSIVATION  
Type: Silicon Oxide and Silicon Nitride  
Thickness: 0.3µm ± 0.03µm to 1.2µm ± 0.12µm  
5
2
< 2 x 10 A/cm  
Transistor Count  
TOP METALLIZATION  
25030  
Type: AlCu (0.5%)  
Thickness: 2.7µm ±0.4µm  
Layout Characteristics  
SUBSTRATE  
Step and Repeat  
Type: Silicon  
Isolation: Junction  
5720µm x 5830µm  
Connect PGND to PGNDx  
Metallization Mask Layout  
ISL70001SEH  
LX1  
PGND1  
LX2  
PVIN2  
PVIN3  
SYNC PVIN1  
PGND2  
M/S  
ZAP  
TDI  
LX3  
TDO  
PGND3  
PGND4  
PGOOD  
SS  
LX4  
DVDD  
PVIN4  
PVIN5  
LX5  
DGND  
PGND  
AGND  
AVDD REF  
FB  
EN PORSEL  
PVIN6  
LX6  
PGND6  
PGND5  
FN7956.0  
November 30, 2011  
15  
ISL70001SEH  
TABLE 1. LAYOUT X-Y COORDINATES  
X
(µm)  
Y
(µm)  
dX  
(µm)  
dY  
(µm)  
BOND WIRES  
PER PAD  
PAD NAME  
PAD NUMBER  
AVDD  
REF  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
28  
29  
30  
31  
32  
33  
34  
1
478  
865  
263  
263  
135  
135  
135  
135  
135  
521  
521  
521  
521  
135  
135  
135  
135  
135  
135  
135  
521  
521  
521  
521  
521  
521  
521  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
521  
521  
521  
521  
521  
521  
521  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
135  
333  
333  
135  
135  
1
1
1
1
1
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
1
1
1
1
1
1
1
2
2
1
1
FB  
1295  
1751  
2151  
2838  
3449  
4060  
4845  
5449  
5449  
5449  
5449  
5449  
5449  
5449  
4941  
4137  
3449  
2838  
2227  
1578  
962  
263  
EN  
263  
PORSEL  
PVIN6  
LX6  
263  
188  
188  
PGND6  
PGND5  
LX5  
188  
188  
925  
PVIN5  
PVIN4  
LX4  
1651  
2263  
2874  
3485  
4096  
4745  
5559  
5559  
5559  
5559  
5559  
5559  
5559  
5559  
5280  
4910  
4540  
4170  
3777  
3425  
2566  
1538  
1018  
654  
PGND4  
PGND3  
LX3  
PVIN3  
PVIN2  
LX2  
PGND2  
PGND1  
LX1  
2
PVIN1  
SYNC  
M/S  
3
4
544  
5
226  
ZAP  
6
226  
TDI  
7
226  
TDO  
8
226  
PGOOD  
SS  
9
226  
10  
11  
12  
13  
14  
226  
DVDD  
DGND  
PGND  
AGND  
226  
226  
226  
226  
FN7956.0  
November 30, 2011  
16  
ISL70001SEH  
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  
FN7956.0  
CHANGE  
November 30, 2011  
Initial Release  
Products  
Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products  
address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks.  
Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a  
complete list of Intersil product families.  
For a complete listing of Applications, Related Documentation and Related Parts, please see the respective device information page on  
intersil.com: ISL70001SEH  
To report errors or suggestions for this datasheet, please go to www.intersil.com/askourstaff  
FITs are available from our website at http://rel.intersil.com/reports/search.php  
For additional products, see www.intersil.com/product_tree  
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted  
in the quality certifications found at www.intersil.com/design/quality  
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  
FN7956.0  
November 30, 2011  
17  

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