DATASHEET
ISL8022
Dual 2A/1.7A Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck
Regulator
The ISL8022 is a high efficiency, dual synchronous step-down
DC/DC regulator that can deliver up to 2A/1.7A continuous
output current per channel. The channels are 180° out-of-
phase for input RMS current and EMI reduction. The supply
voltage range of 2.8V to 5.5V allows for the use of a single Li+
cell, three NiMH cells or a regulated 5V input. The current
mode control architecture enables very low duty cycle
operation at high frequency with fast transient response and
excellent loop stability. The ISL8022 operates at 2.25MHz
switching frequency allowing for the use of small, low cost
inductors and capacitors. Each channel is optimized for
generating an output voltage as low as 0.6V.
The ISL8022 has a user configurable mode of operation-forced
PWM mode and PFM/PWM mode. The forced PWM mode
operation reduces noise and RF interference while the PFM
mode operation provides high efficiency by reducing switching
losses at light loads. In PFM mode of operation, both channels
draw a total quiescent current of only 40µA, hence enabling
high light load efficiency in order to maximize battery life.
The ISL8022 offers a 1ms Power-Good (PG) to monitor both
outputs at power-up. When shutdown, ISL8022 discharges the
outputs capacitor. Other features include internal digital
soft-start, enable for power sequence, overcurrent protection,
and thermal shutdown. The ISL8022 is offered in a
4mmx3mm 12 Ld DFN package with 1mm maximum height.
The complete converter occupies less than 1.8cm
2
area.
FN7650
Rev 3.00
March 14, 2013
Features
• Dual 2A/1.7A high efficiency synchronous buck regulator
with up to 97% efficiency, low iq (40µA)
• 180° out-of-phase
• Start-up with pre-biased output
• Selectable forced PWM mode and PFM mode
• External synchronization up to 8MHz
• Negative current detection and protection
• 100% maximum duty cycle for lowest dropout
• Internal current mode compensation
• Peak current limiting, hiccup mode short circuit protection
and over-temperature protection
• Pb-free (RoHs compliant)
Applications
• DC/DC POL modules
• µC/µP, FPGA and DSP power
• Plug-in DC/DC modules for routers and switchers
• Test and measurement systems
• Li-ion battery powered devices
• Bar code readers
Related Literature
•
AN1554
“ISL8022EVAL1Z Dual 2A/1.7A Low Quiescent
Current 2.25MHz High Efficiency Synchronous Buck
Regulator”
•
AN1587
“ISL8022EVAL2Z Dual 2A/1.7A Low Quiescent
Current 2.25MHz High Efficiency Synchronous Buck
Regulator”
100
90
80
70
60
50
40
3.3V
OUT2 PWM
0.0
0.2
0.4
0.6
0.8
2.5V
OUT1PWM
2.5V
OUT1PFM
3.3V
OUT2PFM
EFFICIENCY (%)
2.25MHz 5V
IN
AT +25°C
1.0
1.2
1.4
1.6
1.8
2.0
OUTPUT LOAD (A)
FIGURE 1. CHARACTERISTIC CURVE
FN7650 Rev 3.00
March 14, 2013
Page 1 of 18
ISL8022
Typical Applications
L1
1 .2 µ H
LX1
PGND
IN P U T 2 .8 V T O 5 .5 V
C2
22µF
R2
316k
C3
10pF
OUTPUT1
2 .5 V /2 A
V IN
EN1
IS L 8 0 2 2
EN2
FB1
R3
100k
C1
2 x 10µF
L2
1 .2 µ H
LX2
C4
22µF
R5
200k
FB2
R6
100k
OUTPUT2
1 .8 V /1 .7 A
PG
PGND
SYNC
C5
10pF
FIGURE 2. TYPICAL APPLICATION DIAGRAM - DUAL INDEPENDENT OUTPUTS
TABLE 1. COMPONENT VALUE SELECTION
V
OUT
C1
C2 (or C4)
C3 (or C5)
L1 (or L2)
R2 (or R5)
R3 (or R6)
0.8V
2x10µF
22µF
10pF
1.0~2.2µH
33k
100k
1.2V
2x10µF
22µF
10pF
1.0~2.2µH
100k
100k
1.5V
2x10µF
22µF
10pF
1.0~2.2µH
150k
100k
1.8V
2x10µF
22µF
10pF
1.2~3.3µH
200k
100k
2.5V
2x10µF
22µF
10pF
1.2~3.3µH
316k
100k
3.3V
2x10µF
22µF
10pF
1.5~4.7µH
450k
100k
In Table 1, the minimum output capacitor value is given for
different output voltage to make sure the whole converter
system is stable. Output capacitance should increase to support
faster load transient requirement.
FN7650 Rev 3.00
March 14, 2013
Page 2 of 18
ISL8022
Block Diagram
SHUTDO W N
EN1
S S o ft -
O FT
S T A Rrt
S ta T
27pF
250k
P W M /P F M
L O G IC
CO NTROLLER
P R O T E C T IO N
D R IV E R
VCC SHUTDO W N
V IN 1
3pF
SLO PE
COMP
FB1
1 .6 k
0 .2 V
SCP
+
+
OCP
+
V IN
1M
PG
0 .5 4 6 V
SHUTDOW N
EN2
S O o ft-
SFT
S TS ta rt
ART
3pF
SLO PE
COMP
FB2
1 .6 k
0 .2 V
SCP
+
+
OCP
+
0 .5 4 6 V
FN7650 Rev 3.00
March 14, 2013
+
B A N D G A P 0 .6 V
+
+
+
B A N D G A P 0 .6 V
EAMP
+
COMP
LX1
PGND
+
CSA1
1 .2 5 V
O S C IL L A T O R
+
S K IP
0 .2 6 5 V
N E G A T IV E
C U R R E N T L IM IT
1m s
DELAY
Z E R O-C R O S S
S E N S IN G
SYNC
SHUTDO W N
VCC
27pF
250k
SHUTDO W N
V IN 2
EAMP
+
COMP
P W M /P F M
L O G IC
CO NTROLLER
P R O T E C T IO N
D R IV E R
THERM AL
SHUT DOW N
LX2
PGND
+
CSA2
1 .1 V
+
S K IP
0 .2 6 5 V
N E G A T IV E
C U R R E N T L IM IT
Z E R O-C R O S S
S E N S IN G
Page 3 of 18
ISL8022
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
ISL8022IRZ
PART TEMP. RANGE
MARKING
(°C)
8022
-40 to +85
PACKAGE
(Pb-Free)
PKG.
DWG. #
12 Ld 4x3 DFN L12.4x3
Pin Configuration
ISL8022
(12 LD DFN)
TOP VIEW
FB1
EN1
PG
VIN1
LX1
PGND1
1
2
3
4
5
6
PAD
12 FB2
11 EN2
10 SYNC
9
8
7
VIN2
LX2
PGND2
ISL8022EVAL1Z Evaluation Board
ISL8022EVAL2Z Evaluation Board
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
ISL8022.
For more information on MSL please see
techbrief
TB363.
Pin Description
PIN
NUMBER
1
SYMBOL
FB1
DESCRIPTION
The feedback network of the Channel 1 regulator. FB1 is the negative input to the transconductance error amplifier. The
output voltage is set by an external resistor divider connected to FB1. With a properly selected divider, the output voltage
can be set to any voltage between the power rail (reduced by converter losses) and the 0.6V reference. There is an internal
compensation to meet a typical application. In addition, the regulator power-good and undervoltage protection circuitry
use FB1 to monitor the Channel 1 regulator output voltage.
Regulator Channel 1 enable pin. Enable the output, V
OUT1
, when driven to high. Shutdown the V
OUT1
and discharge output
capacitor when driven to low. Do not leave this pin floating.
1ms timer output. At power-up or EN_ HI, this output is a 1ms delayed Power-Good signal for both the V
OUT1
and V
OUT2
voltages. There is an internal 1M pull-up resistor.
Input supply voltage for Channel 1. Connect 10µF ceramic capacitor to PGND1.
Switching node connection for Channel 1. Connect to one terminal of inductor for V
OUT1
.
Negative supply for power stage 1.
Negative supply for power stage 2 and system ground.
Switching node connection for Channel 2. Connect to one terminal of inductor for V
OUT2
.
Input supply voltage for Ch 2 and to provide logic bias. Make sure that V
IN2
is
≥
V
IN1
. Connect 10µF ceramic capacitor to
PGND2.
Mode Selection pin. Connect to logic high or input voltage VIN for PFM mode; connect to logic low or ground for forced PWM
mode. Connect to an external function generator for Synchronization. Negative edge trigger. Do not leave this pin floating.
Regulator Channel 2 enable pin. Enable the output, V
OUT2
, when driven to high. Shutdown the V
OUT2
and discharge output
capacitor when driven to low. Do not leave this pin floating.
The feedback network of the Channel 2 regulator. FB2 is the negative input to the transconductance error amplifier. The
output voltage is set by an external resistor divider connected to FB2. With a properly selected divider, the output voltage
can be set to any voltage between the power rail (reduced by converter losses) and the 0.6V reference. There is an internal
compensation to meet a typical application. In addition, the regulator power-good and undervoltage protection circuitry
use FB2 to monitor the Channel 2 regulator output voltage.
The exposed pad must be connected to the SGND pin for proper electrical performance. Add as much vias as possible for
optimal thermal performance.
2
3
4
5
6
7
8
9
10
11
12
EN1
PG
VIN1
LX1
PGND1
PGND2
LX2
VIN2
SYNC
EN2
FB2
-
EXPOSED
PAD
FN7650 Rev 3.00
March 14, 2013
Page 4 of 18
ISL8022
Absolute Maximum Ratings
(Reference to GND)
Supply Voltage (V
IN
) . . . . . . . . . . . . . . . . . . . . -0.3V to 6V (DC) or 7V (20ms)
EN1, EN2, PG, SYNC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.3V to V
IN
+ 0.3V
LX1, LX2. . . . . . . . . . . . . . . . . . . . . . . -1.5V (100ns)/-0.3V (DC) to 6.5V (DC)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . or 7V (20ms)
FB1, FB2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 2.7V
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3kV
Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250V
Charged Device Model (Tested per JESD22-C101E). . . . . . . . . . . . . . . 2k
Latch Up (Tested per JESD-78B; Class 2, Level A) . . . . . . . . . . . . . . 100mA
Thermal Information
Thermal Resistance (Typical)
JA
(°C/W)
JC
(°C/W)
4x3 DFN Package (Notes 4, 5) . . . . . . . .
41
3
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-55°C to +150°C
Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
V
IN
Supply Voltage Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8V to 5.5V
Load Current Range Channel 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0A to 2A
Load Current Range Channel 2 . . . . . . . . . . . . . . . . . . . . . . . . . . 0A to 1.7A
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.
JA
is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
Brief
TB379.
5.
JC
, “case temperature” location is at the center of the exposed metal pad on the package underside.
Electrical Specifications
Unless otherwise noted, all parameter limits are established over the recommended operating
conditions: T
A
= -40°C to +85°C, V
IN
= 2.8V to 5.5V, EN1 = EN2 = V
IN
, SYNC = 0V, L = 1.2µH, C1 = 2 x 10µF, C2 = C4 = 22µF, I
OUT1
= 0A to 2A,
I
OUT2
= 0A to 1.7A. (Typical values are at T
A
= +25°C, V
IN
= 3.6V). Boldface limits apply over the operating temperature range, -40°C to +85°C.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
(Note 6)
TYP
MAX
(Note 6)
UNITS
INPUT SUPPLY
V
IN
Undervoltage Lock-out Threshold
V
UVLO
Rising
Falling
Quiescent Supply Current
I
VIN
SYNC = V
IN
, EN1 = EN2 = V
IN
, no switches
switching
SYNC = GND, EN1 = EN2 = V
IN
, F
S
= 2.25MHz,
no load at the output
ShutDown Supply Current
I
SD
V
IN
= 5.5V, EN1 = EN2 = GND
2.0
2.5
2.4
40
0.86
6.5
55
1
12
2.8
V
V
µA
mA
µA
OUTPUT REGULATION
FB1, FB2 Regulation Voltage
FB1, FB2 Bias Current
Output Voltage Accuracy
V
FB_
I
FB_
VFB = 0.55V
SYNC = V
IN
, Io = 0A to 2A
SYNC = GND, Io = 0A to 2A
Line Regulation
Soft-Start Ramp Time Cycle
V
IN
= V
O
+ 0.5V to 5.5V (minimal 2.8V)
0.590
0.6
0.1
±1.5
±1
0.2
1.3
0.610
V
µA
%
%
%/V
ms
OVERCURRENT PROTECTION
Dynamic Current limit ON-time
Dynamic Current Limit OFF-time
Peak Overcurrent Limit
t
OCON
t
OCOFF
I
pk1
I
pk2
Peak SKIP Limit
I
skip1
I
skip2
2.7
2.3
520
520
17
4
3.2
2.8
610
610
3.6
3.2
730
730
Clock
pulses
SS cycle
A
A
mA
mA
FN7650 Rev 3.00
March 14, 2013
Page 5 of 18
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