Product Summary - Skyworks Solutions, Inc.

PRODUCT SUMMARY
SKY87202: 3.5 A Constant On-Time, Step-Down DC-DC Converter
Applications
Description
 Portable devices
The SKY87202 is a 1.2 MHz, 3.5 A constant on-time, synchronous
step-down DC-DC converter. The device provides an output
voltage from 0.6 V to 3.3 V from input voltage ranging from 2.7 V
to 6.0 V, while keeping excellent line and load regulation and
maximizing input efficiency.
 Access points
 Set top boxes
The constant on-time control allows easy loop stabilization with
minimal external components while providing fast transient
response.
Features
 Input voltage range: 2.7 V to 6.0 V
 Two output voltage options:
 Adjustable output voltage: 0.6 V to 3.3 V (SKY87202-11)
 Fixed output voltage: 1.2 V (SKY87202-12)
Power sequencing is controlled by the EN and PG pins.
 Up to 3.5 A continuous output current
The SKY87202 is available in a 12-pin, 2 mm  2 mm Quad Flat
No-Lead (QFN) package.
 Switching frequency: 1.2 MHz
 95% peak efficiency
 Typical switch on resistance: 50 m PMOS, 40 m NMOS
 80% light load efficiency
The SKY87202 has cycle-by-cycle current limits and thermal
shutdown to protect against fault conditions.
A typical application circuit is shown in Figure 1. The pin
configuration and packages are shown in Figure 2. A functional
block diagram of the SKY87202 is shown in Figure 3.
 Power sequencing
 Cycle-by-cycle over-current protection
Skyworks Green™ products are compliant with
all applicable legislation and are halogen-free.
For additional information, refer to Skyworks
Definition of Green™, document number
SQ04-0074.
 Over-temperature protection
 Control loop stabilization with low ESR ceramic capacitors
 Soft start
 Low profile, QFN (12-pin, 2 mm  2 mm) package (MSL1, 260
C per JEDEC J-STD-020)
SKY87202
1
C1
22 μF
10
PVIN
VIN
8
EN
Power Good
9
PG
AGND
Enable
4
LX
OUT
FB/NC
NC
2, 11
1 μH
L1
C2
22 μF
6
R1
57.6 kΩ
R2
57.6 kΩ
Output Voltage
1.2 V
7
5
×
PGND
Input Voltage
2.7 V to 6 V
3, 12
t0281
Figure 1. Typical Application Circuit
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
203141A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • February 27, 2014
1
VIN
PRODUCT SUMMARY • SKY87202 STEP-DOWN DC-DC CONVERTER
PVIN 1
10
9 PG
LX
LX 2
11
8 EN
PGND
12
7 FB/NC
AGND 4
5
6 OUT
NC
PGND 3
S3184
Figure 2. SKY87202-11/-12 Pinout – 12-Pin QFN Packages
(Top View)
VIN
Current Limit
Comparator
Voltage
References
and UVLO
EN
–
VREF
+
FB/NC
PVIN
+
HSG
+
COMP
–
PWM
Control
and
Logic
Ramp
Circuit
HS
MOSFET
Driver
SW
OUT
LX
RDAMP
VOUT
Discharge
200 kΩ
LSG
LS
MOSFET
Internal FB for fixed output voltage
200 kΩ
–
+
fSET
0.66 V +
PGND
Discontinuous Conduction Mode
Comparator
–
+
0.54 V
PG
–
t0279
Figure 3. SKY87202 Functional Block Diagram
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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February 27, 2014 • Skyworks Proprietary and Confidential information • Products and Product Information Are Subject To Change Without Notice • 203141A #
PRODUCT SUMMARY • SKY87202 STEP-DOWN DC-DC CONVERTER
Ordering Information
Model Name
SKY87202 step-down DC-DC converter
Manufacturing Part Number
Evaluation Board Part Number
SKY87202-11-631LF (variable output voltage)
SKY87202-11-631LF-EVB
SKY87202-12-631LF (fixed 1.2 V output voltage)
SKY87202-12-631LF-EVB
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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
203141A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • February 27, 2014
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