ISL95901
NOT RECOMMENDED FOR NEW DESIGNS
NO RECOMMENDED REPLACEMENT
contact our Technical Support Center at
1-888-INTERSIL or www.intersil.com/tsc
DATASHEET
FN7893
Rev 1.00
January 22, 2015
Wide V
IN
Dual Integrated Buck Regulator With 4A/4A Continuous Output Current
and LDOs
The ISL95901 is a dual, high-efficient buck regulator capable
of 4A per channel continuous output current. It integrates two
LDOs and one low-impedance switch. This power management
IC delivers power in portable and embedded systems. With an
input range of 4.5V to 16V, it provides a high frequency power
solution for a variety of point-of-load applications. Outputs are
adjustable to meet system needs.
A PWM controller drives two pairs of internal switching
N-channel power MOSFETs to generate output voltage. The
integrated power switch is optimized for excellent thermal
performance for up to 4A of output current per channel.
The ISL95901 modulator features Intersil R4™ Technology,
which combines the best features of fixed-frequency and
hysteretic PWMs while eliminating many of their drawbacks.
Like R3™ Technology, the R4™ Technology allows variable
frequency in response to load transients and maintains the
benefits of current-mode hysteretic controllers. In addition, it
reduces regulator output impedance and uses accurate
referencing to eliminate the need for a high-gain voltage
amplifier. The resulting topology can be tuned to voltage-mode
hysteretic transient speed while maintaining a linear control
model. This topology removes the need for compensation,
which greatly simplifies regulator design for customers and
reduces external component count and cost.
Protection features include overcorrect, negative overcorrect,
UVLO and thermal overload. The ISL95901 is available in a
46 Ld 5mmx6mm Quad Flat (QFN) Pb-free package.
Features
• Wide input voltage range from 4.5V to 16V
• Adjustable output voltages with continuous output current
up to 4A
• 1% accuracy over temperature and V
CC
range
• Built-in low-power LDO for external µC
• Built-in compensation
• Internally set SS and OCP
• Independent enable, power-good and standby control inputs
for each output
• Innovative R4™ Modulator
• Boot undervoltage detection
Applications
• General purpose, point-of-load DC/DC power conversion
• Notebook, netbook and tablet
• Embedded computing system
Related Literature
• See
AN1743
“Wide V
IN
Dual Integrated Buck Regulator With
4A/4A Continuous Output Current and LDOs”
00
90
EFFICIENCY (%)
80
70
60
50
40
6V
IN
PFM
6V
IN
PWM
12V
IN
PFM
I
OUT
R4
R3
V
COMP
f
SW
= 300kHz, V
OUT
= 5V
8.4V
IN
PFM
8.4V
IN
PWM
12V
IN
PWM
V
OUT
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
t
OUTPUT LOAD (A)
FIGURE 1. EFFICIENCY vs LOAD, V
IN
= 12V, T
A
= +25°C
FIGURE 2. R3™ vs R4™ IDEALIZED TRANSIENT RESPONSE
FN7893 Rev 1.00
January 22, 2015
Page 1 of 24
ISL95901
Table of Contents
Pin Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical Performance Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Detailed Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
R4™ Modulator Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transient Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discontinuous Conduction Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation Initialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enable and Disable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discharge Mode (Soft-stop) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-good. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Protection Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buck Regulator Overcurrent Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buck Negative Current Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Standby Output Overcurrent Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Overload Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BOOT Undervoltage Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Application Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Inductor Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buck Regulator Output Capacitor Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Derating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Layout Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
19
19
20
20
20
20
20
20
20
20
21
21
21
21
21
21
21
21
21
22
22
22
Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
About Intersil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
FN7893 Rev 1.00
January 22, 2015
Page 2 of 24
ISL95901
Pin Configuration
ISL95901
(46 LD QFN)
TOP VIEW
VSOUT2
38
LDO3P3
BYP3P3
MODE
LDO5
BYP5
VCC
PG1
46
45
44
43
42
41
40
39
PG2
37
VIN
FS 1
VSIN1 2
FB1 3
GND 4
EN1 5
BOOT1 6
PHASE1 7
PHASE1 8
PGND1 9
PGND1 10
PGND1 11
PGND1 12
PGND1 13
PAD2
PAD3
PHASE1
PHASE2
PAD1
GND
36 STB2
35 VSIN2
34 FB2
33 GND
32 EN2
31 BOOT2
30 PHASE2
29 PHASE2
28 PGND2
27 PGND2
26 PGND2
25 PGND2
24 PGND2
14
PHASE1
15
VIN1
16
VIN1
17
VIN1
18
PHASE1
19
PHASE2
20
VIN2
21
VIN2
22
VIN2
23
PHASE2
Pin Descriptions
PIN NUMBER
1
2
3
4, 33, PAD1
5
6
SYMBOL
FS
VSIN1
FB1
GND
EN1
BOOT1
PIN DESCRIPTION
Buck switching frequency selection. Tie to high for 1MHz, float for 500kHz, tie to GND for 300kHz.
Sensing for output of Switching Mode Power Supply 1 -SMPS1. Must be connected to channel 1 output side
of inductor.
SMPS1 feedback input. Connect FB1 to a resistive voltage divider from SVIN1 to GND1 to adjust the output
from 0.8V to 5.5V.
Analog ground for buck controllers and LDOs. Kelvin connect GND to the negative terminal of SMPS1/2. For
optimal thermal performance, place as many vias as possible under PAD1 and connecting to GND plane.
SMPS1 controller enable input. PWM controller is held off when pin is pulled to ground. When voltage on
this pin rises above 1.4V, PWM controller is enabled.
Floating bootstrap supply pin for power MOSFET gate driver. Bootstrap capacitor provides necessary charge
to turn on high-side internal N-channel MOSFET of channel 1. Connect an external capacitor from this pin to
PHASE1.
Switch node output of channel 1. Connects source of internal power MOSFETs with external output inductor.
Connect exposed PAD2 as close to inductor of SMPS1 as possible.
Power ground of SMPS1.
7, 8, 14, 18,
PAD2
9, 10, 11, 12, 13
PHASE1
PGND1
FN7893 Rev 1.00
January 22, 2015
Page 3 of 24
ISL95901
Pin Descriptions
(Continued)
PIN NUMBER
15, 16, 17
19, 23, 29, 30,
PAD3
20, 21, 22
24, 25, 26, 27,
28
31
SYMBOL
VIN1
PHASE2
VIN2
PGND2
BOOT2
PIN DESCRIPTION
Input supply for power stage of SMPS1 regulator and source for internal linear regulator, LDO. For
decoupling, place a minimum of 10µF ceramic capacitance from VIN1 to PGND1 and close to IC.
Switch node output of channel 2. Connects source of internal power MOSFETs with external output inductor.
Connect exposed PAD3 as close to inductor of SMPS2 as possible.
Input supply for power stage of SMPS2 regulator. For decoupling, place a minimum of 10µF ceramic
capacitance from VIN2 to PGND2 and close to the IC.
Power ground of SMPS2.
Floating bootstrap supply pin for power MOSFET gate driver. Bootstrap capacitor provides necessary charge
to turn on high-side internal N-channel MOSFET of channel 2. Connect an external capacitor from this pin to
PHASE2.
SMPS2 controller enable input. PWM controller is held off when pin is pulled to ground. When voltage on
this pin rises above 1.4V, PWM controller is enabled.
SMPS2 feedback Input. Connect FB2 to a resistive voltage divider from SVIN2 to GND2 to adjust the output
from 0.8V to 5.5V.
Sensing for output of SMPS2. Must be connected to channel 2 output side of inductor.
Standby output 2 enable input. Standby output 2 is held off when pin is pulled to ground. When voltage on
this pin rises above 1.4V, standby output 2 controller is enabled.
Open drain power-good of SMPS2. Pulled to ground when output voltage is below regulation limits or during
soft-start interval. Contains an internal 5MΩ pull-up resistor.
Standby output 2. There is a switch between VSIN2 and VSOUT2.
Connect BYP5 to 5V buck output or external 5V source, this will allow IC to disable VCC and LDO5, then the
power source will be drawn from BYP5 to minimize internal power dissipation. Tie to GND if not use.
Voltage bias for gate drivers as well as all other control circuitries. Power on or off by VIN. Decouple with at
least 1µF of an MLCC capacitor across VCC and PAD1.
Input LDO3P3, LDO5 and VCC. For decoupling, place a minimum of 1µF ceramic capacitance close to IC.
5V linear regulator output. Power on or off by VIN. Can provide a total of 100mA external loads. Bypass
LDO5 output with a minimum of 4.7µF ceramic.
Connect BYP3P3 to 3.3V buck output or external 3.3V source, this will allow IC to disable LDO3P3, then the
power source will be drawn from BYP3P3 to minimize internal power dissipation. Tie to GND if not used.
Mode selection pin. Connect to logic high or VCC for PWM mode. Connect to logic low or ground for DCM
mode. An internal 5MΩ pull-down resistor prevents undefined logic state in case of MODE pin float.
3.3V linear regulator output. Power on or off by VIN. Can provide a total of 100mA external loads. Bypass
LDO3P3 output with a minimum of 4.7µF ceramic.
Open drain power-good of SMPS1. Pulled to ground when output voltage is below regulation limits or during
soft-start interval. Contains an internal 5MΩ pull-up resistor.
32
34
35
36
37
38
39
40
41
42
43
44
45
46
EN2
FB2
VSIN2
STB2
PG2
VSOUT2
BYP5
VCC
VIN
LDO5
BYP3P3
MODE
LDO3P3
PG1
Ordering Information
PART NUMBER
(Notes
1, 2, 3)
ISL95901IRZ
ISL95901EVAL1Z
NOTES:
1. Add “-T*” suffix for tape and reel. 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
ISL95901.
For more information on MSL please see Tech Brief
TB363.
PART
MARKING
95901 IRZ
Evaluation Board
TEMP. RANGE
(°C)
-40 to +85
PACKAGE
(RoHS Compliant)
46 Ld QFN
PKG.
DWG. #
L46.5x6
FN7893 Rev 1.00
January 22, 2015
Page 4 of 24
ISL95901
Typical Application Schematic
VIN: 4.5V TO 16V
2
C
5
1µF
LDO5
5V
C
6
4.7µF
1µF
VCC
LDO3P3
3.3V
C
7
4.7 µF
C
1
10µF
LDO3P3
VIN1
LDO5
VIN2
VIN
C
2
10µF
10
BOOT1
OUT1
3.3V/4A
C
3
2x47µF
PGND1
(KELVIN SENSE)
C
9
100pF
R
1
31.6kΩ
R
2
10kΩ
GND1
FB1
L
1
: 1µH
C
4
0.1µF
BOOT2
PHASE2
(PAD3)
C
6
0.1µF
OUT2
L
2
: 1.5µH 5V/4A
C
4
2x47µF
PGND2
GND2
FB2
(KELVIN SENSE)
C
10
100pF
PHASE1
(PAD2)
ISL95901
GND
VSIN1
FS
FS
VSOUT2
VSIN2
R
3
52.3kΩ
R
4
10kΩ
VSOUT2
5V
C
8
4.7µF
VIN
EN1
VIN
EN2
PG1
PG2
VCC
STB2
PAD1
MODE
FIGURE 3. DUAL 4A OUTPUT AT 1MHz (V
IN
RANGE FROM 4.5V TO 16V)
FN7893 Rev 1.00
January 22, 2015
Page 5 of 24
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