003A Просмотр технического описания (PDF) - Intersil
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003A Datasheet PDF : 23 Pages
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DATASHEET
ISL85003, ISL85003A
Highly Efficient 3A Synchronous Buck Regulator
FN7968
Rev.2.00
Jan 15, 2016
The ISL85003 and ISL85003A are synchronous buck regulators
with integrated high-side and low-side FETs. The regulator can
operate from an input voltage range of 4.5V to 18V while
delivering a very efficient continuous 3A current. This is all
delivered in a very compact 3mmx4mm DFN package.
The ISL85003 is designed on Intersil’s proprietary fab process
that is designed to deliver very low rDS(ON) FETs with an
optimized current mode controller wrapped around it. The
high-side NFET is designed to have an rDS(ON) of 65mΩ while
the low-side NFET is designed to have an rDS(ON) of 45mΩ.
With these two FETs, the device delivers very high efficiency
power to the load.
The ISL85003 can automatically switch between DCM and
CCM for light-load efficiency in DCM. The switching frequency
in CCM is internally set to 500kHz.
The device provides a maximum static regulation tolerance of
±1% over wide line, load and temperature ranges. The output
is user adjustable, with external resistors, down to 0.8V. Pulling
EN above 0.6V enables the controller. The regulator supports
prebiased output.
Fault protection is provided by internal current limiting during
positive or negative overcurrent conditions, output and input
under and overvoltage detection and an over-temperature
monitoring circuit.
Related Literature
• AN1935, “ISL85003DEMO1Z, ISL85003ADEMO1Z
Evaluation Board User Guide”
• AN1930, “ISL85003EVAL2Z, ISL85003AEVAL2Z Evaluation
Board User Guide”
• AN1965, “Effectively Using the Intersil Small Form Factor
Power Management Evaluation Boards”
Features
• Input voltage range 4.5V to 18V
• Output voltage adjustable from 0.8V, ±1%
• Efficiency up to 95%
• Integrated boot diode with undervoltage detection
• Current mode control
- DCM/CCM
- Internal or external compensation options
- 500kHz switching frequency option
- External synchronization up to 2MHz on ISL85003
• Adjustable soft-start time on the ISL85003A
• Open-drain PG window comparator
- Built-in protection
- Positive and negative overcurrent protection
- Overvoltage and thermal protection
- Input overvoltage protection
• Small 12 Ld 3mmx4mm Dual Flat No-Lead (DFN) package
Applications
• Network and communication equipment
• Industrial process control
• Multifunction printers
• Point-of-load regulators
• Standard 12V rail supplies
• Embedded computing
tSS = 2ms, FIXED
U1 ISL85003
SYNC
L
=
0.5V
L=
H=
DE
1.20V POS
H = FPWM
EDGE
1
SYNC
PG
2
OPEN DRAIN, ADD PULL-UP
PG
EN
3
THRESHOLD 1V, HYST 100mV
EN
AGND
4.C7p1 F
+0.8V ±8mV 4 FB
R1
301k
1%
R2
57.1k
1%
5
COMP
6 AGND
BOOT 12 C3 0.1µF
11 C4 1µF
VDD
+5V
VIN 10
4.5 TO 18V
VIN
VIN 9
C5
10µF
C6
10µF
GND
PHASE 8
PHASE 7
L1
fSW = 500kHz 4.7µH
DEVICE MUST BE
CONNECTED TO GND
PLANE WITH 8 VIAs.
C8
47µF
+5V
MAX 3A
VOUT
C9,22µF
GND
OPTIONAL CAP
NO CAP: tSS = 2ms
For tSS>2ms, ADD CAP:
U1 ISL85003A
C[nF] = 4.1 * tSS[ms]-1.6nF
2C2n2F
SS
1 SYNC
BOOT 12 C3 0.1µF
PG
2
OPEN DRAIN, ADD PULL-UP
PG
EN
3 EN
THRESHOLD 1V, HYST 100mV
AGND
+0.8V ±8mV 4 FB
4.C7p1F
R1
301k
1%
R2
57.1k
1%
5
COMP
6 AGND
11 C4 1µF
VDD
+5V
VIN 10
4.5 TO 18V
VIN
C5
C6
VIN 9
10µF
10µF
GND
PHASE 8
PHASE 7
L1
fSW = 500kHz 4.7µH
C8
47µF
+5V
MAX 3A
VOUT
C9,22µF
GND
DEVICE MUST BE
CONNECTED TO GND
PLANE WITH 8 VIAs.
+5V
FIGURE 1A. ISL85003 VIN RANGE FROM 4.5V TO 18V, VOUT = 5V AND
INTERNAL COMPENSATION WITH EXTERNAL
FREQUENCY SYNC
FIGURE 1B. ISL85003A VIN RANGE FROM 4.5V TO 18V, VOUT = 5V
AND INTERNAL COMPENSATION WITH EXTERNAL
SOFT-START
FIGURE 1. TYPICAL APPLICATION SCHEMATICS
FN7968 Rev.2.00
Jan 15, 2016
Page 1 of 23
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