FR9701S9G [FITIPOWER]
23V, 2A, 600KHz Asynchronous Synchronous Step-Down DC/DC Converter;
| 型号： | FR9701S9G |
| 厂家： | 
Fitipower |
| 描述： | 23V, 2A, 600KHz Asynchronous Synchronous Step-Down DC/DC Converter |
| 文件： | 总12页 (文件大小：698K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
fitipower integrated technology lnc.
23V, 2A, 600KHz Asynchronous Synchronous
Step-Down DC/DC Converter
Description
Features
The FR9701 is a monolithic step-down switch mode
converter with a built-in power MOSFET. It
achieves 2A output current over a wide input supply
range with excellent load and line regulation.
Current mode operation provides fast transient
● 2A Output Current
● 180mΩ Internal Power MOSFET Switch
● Stable with Low ESR Output Ceramic Capacitors
● Up to 92% Efficiency
● Fixed 600KHz Frequency
● Current Mode Operation
● Over-Temperature Protection with Hiccup-Mode
● Cycle-by-Cycle Over Current Protection
● Wide 4.5V to 23V Operating Input Range
● Output Adjustable from 0.805V to 15V
● 10μA Shutdown Current
response and eases loop stabilization.
Fault
condition protection includes cycle-by-cycle current
limit and over temperature protection.
The FR9701 requires a minimum number of
available standard external components.
The
FR9701 is available in TSOT-23-6 and SOT-23-6
packages.
● Available in TSOT-23-6 and SOT-23-6 Packages
Applications
● Battery Charger
● Pre-Regulator for Linear Regulator
● OLPC, Netbook
● Distributed Power System
● WLED Driver
Pin Assignments
Ordering Information
S6 Package (SOT-23-6)
FR9701□□□
SW
EN
4
VIN
TR: Tape/Reel
G: Green
6
5
(Marking)
2
1
3
Package Type
S6: SOT-23-6
S9: TSOT-23-6
BS GND FB
SOT-23-6 Marking
S9 Package (TSOT-23-6)
Part Number
Product Code
t7G
SW
EN
4
VIN
5
FR9701S6G
6
1
TSOT-23-6 Marking
Part Number
(Marking)
2
3
Product Code
t8G
FR9701S9G
BS GND FB
Figure 1. Pin Assignment of FR9701
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Typical Application Circuit
5
1
6
BS
VIN
4.5V to 23V
VIN
C3
22nF
VOUT
3.3V
L1
4.7μH
C1
10μF/25V
CERAMIC
FR9701 SW
D1
B230A
C4(optional)
10nF
R1
30.9KΩ/1%
4
OFF
EN
ON
3
C2
FB
GND
47μF/6.3V
CERAMIC
R2
10KΩ/1%
2
Figure 2. Output 3.3V Application Circuit
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Functional Pin Description
Pin Name
Pin Function
Bootstrap. A 22nF capacitor is connected between SW and BS pins to drive the power switch’s gate above the
supply voltage.
BS
GND
FB
Ground Pin.
Feedback. An external resistor divider from the output to GND, tapped to the FB pin sets the output voltage.
On/Off Control Input. Pull EN above 1.2V and below 5V to turn the device on.
EN
Power Supply Input. Drive 4.5V to 23V voltage to this pin to power on this chip. Connect a 10μF ceramic bypass
capacitor between VIN and GND to eliminate noise.
VIN
SW
Switch Output. Connect this pin to the switch end of the inductor.
Block Diagram
VIN
Internal
Regulator
UVLO
&
POR
OVP
OTP
VCC
VCC
ISEN
EN
950K
BS
Oscillator
Current
High-Side
MOSFET
S
R
Comparator
Error
Driver
Logic
PWM
Control
Amplifier
SW
FB
OVP
OTP
UVLO
CCOMP
RCOMP
0.805V
Current
Limit
GND
Figure 3. Block Diagram of FR9701
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Absolute Maximum Ratings
● Input Supply Voltage (VIN) --------------------------------------------------------------------------------- +25V
● VSW -------------------------------------------------------------------------------------------------------------- -0.3V to VIN +0.3V
● VBS --------------------------------------------------------------------------------------------------------------- Vsw +6V
● All Other Pins Voltage -------------------------------------------------------------------------------------- -0.3V to +6V
● Maximum Junction Temperature (TJ) ------------------------------------------------------------------- +150°C
● Storage Temperature (TS) --------------------------------------------------------------------------------- -65°C to +150°C
● Lead Temperature (Soldering, 10sec.) ----------------------------------------------------------------- +260°C
● Power Dissipation @ TA=25°C, (PD)
SOT-23-6 ------------------------------------------------------------------------------------------- +0.4W
TSOT-23-6 ----------------------------------------------------------------------------------------- +0.4W
● Package Thermal Resistance, (θJA)
SOT-23-6 ------------------------------------------------------------------------------------------- +250°C/W
TSOT-23-6 ----------------------------------------------------------------------------------------- +250°C/W
● ESD Susceptibility
HBM (Human Body Mode) -------------------------------------------------------------------------------- 2KV
Note 1：Stresses exceed those ratings may damage the device.
Recommended Operating Conditions
● Input Supply Voltage (VIN) --------------------------------------------------------------------------------- +4.5V to +23V
● Output Voltage (VOUT) --------------------------------------------------------------------------------------- +0.805V to +15V
● Operation Temperature Range --------------------------------------------------------------------------- -40°C to +85°C
Note 2：If out of its operation conditions, the device is not guaranteed to function.
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Electrical Characteristics
(VIN=12V, TA=25°C, unless otherwise specified.)
Parameter
Test Conditions
4.5V ≤ VIN ≤ 23V
Min
Typ
0.805
180
Max
Unit
V
Feedback Voltage
0.785
0.825
Switch-On Resistance (*)
Switch Leakage
mΩ
μA
A
VEN = 0V, VSW = 0V
10
Current Limit (*)
3
Oscillator Frequency
480
600
120
85
720
KHz
KHz
%
Fold-back Frequency
VFB = 0V
Maximum Duty Cycle
Minimum On-Time (*)
100
4.4
250
ns
Under Voltage Lockout Threshold Rising
Under Voltage Lockout Threshold Hysteresis
EN Input Low Voltage
4.1
1.2
4.7
0.4
V
mV
V
EN Input High Voltage
V
VEN = 2V
2.0
0.1
10
μA
μA
μA
mA
°C
EN Input Current
VEN = 0V
Supply Current (Shutdown)
VEN = 0V
Supply Current (Quiescent)
VEN = 2V, VFB = 1V
1.8
150
Over-Temperature Protection Threshold (*)
* Guaranteed by design
Note 3：VIN = 5V, VOUT = 3.3V, maximum load current is about 1.4A.
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Typical Performance Curves
VIN = 12V, VOUT = 3.3V, C1 = 10μF, C2 = 47μF, L1 = 4.7μH, TA = +25°C, unless otherwise noted.
VIN= 12V
VIN= 5V
Figure 4. Efficiency vs. Loading
Figure 5. Efficiency vs. Loading
650
640
630
620
610
600
590
580
570
560
550
0.82
0.818
0.816
0.814
0.812
0.81
IOUT= 0.5A
IOUT= 0.5A
0.808
0.806
0.804
0.802
0.8
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
90 100
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
90 100
Case Temperature (℃ )
Case Temperature ( ℃ )
Figure 6. Feedback Voltage vs. Case Temperature
Figure 7. Switching Frequency vs. Case Temperature
IOUT = 0.1A
IOUT = 2A
VIN 50mV/div.
VOUT 10mV/div.
VIN 200mV/div.
VOUT 10mV/div.
IL 1A/div.
IL 1A/div.
VSW 5V/div.
VSW 5V/div.
1μs/div.
1μs/div.
Figure 8. DC Ripple Waveform
Figure 9. DC Ripple Waveform
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Typical Performance Curves (Continued)
VIN = 12V, VOUT = 3.3V, C1 = 10μF, C2 = 47μF, L1 = 4.7μH, TA = +25°C, unless otherwise noted.
IOUT=0.1A
IOUT=2A
VEN, 5V/div.
VEN, 5V/div.
VOUT 1V/div.
VOUT 1V/div.
IL 1A/div.
IL 1A/div.
VSW 10V/div.
VSW 10V/div.
80μs/div.
80μs/div.
Figure 10. Startup Through Enable Waveform
IOUT=0.1A
Figure 11. Startup Through Enable Waveform
IOUT=2A
VEN, 5V/div.
VEN, 5V/div.
VOUT 1V/div.
VOUT 1V/div.
IL 1A/div.
IL 1A/div.
VSW 10V/div.
VSW 10V/div.
1ms/div.
80μs/div.
Figure 12. Shutdown Through Enable Waveform
Figure 13. Shutdown Through Enable Waveform
VOUT 1V/div.
VOUT 1V/div.
IL 1A/div.
IL 1A/div.
40μs/div.
20μs/div.
Figure 14. Short Circuit Test Waveform
Figure 15. Short Circuit Recovery Waveform
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Typical Performance Curves (Continued)
VIN = 12V, VOUT = 3.3V, C1 = 10μF, C2 = 47μF, L1 = 4.7μH, TA = +25°C, unless otherwise noted.
IOUT=100mA to 2A step
VOUT ,, 200mV/div.
IL 1A/div.
400μs/div.
Figure 16. Load Transient Waveform
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Application Information
Setting EN Automatic Startup Voltage
Table 2 -- Resistor Selection for Common
Output Voltages
VIN
VOUT
R1
R2
5V
43kΩ
30.9kΩ
21kΩ
8.2kΩ
10kΩ
10kΩ
10kΩ
10kΩ
R3
FR9701
EN
5V
3.3V
2.5V
1.8V
1.2V
950KΩ
R4
12.4kΩ
4.99kΩ
The external resistor divider is used to set the EN
automatic startup voltage:
Selecting the Inductor
VEꢁ
A 4.ꢄμH inductor with a DC current rating of at least
25% percent higher than the maximum load current
is recommended for most applications. For highest
efficiency, the inductor’s DC resistance should be
less than 200mΩ. For most designs, the required
inductance value can be derived from the following
equation.
R4ꢀ
VIꢁꢂV
Eꢁꢀ
R3
For example, VIN ꢀ12V, R3 ꢀ 100KΩ, thus R4 resistor
value is:
5V
R4ꢀ
ꢃꢄ1.5kΩ
12Vꢂ5V
100kΩ
ꢇIꢀ0.3ꢅIꢈ(MAXꢉ
ꢀ
VOUT
FSWꢅꢇIꢅVIꢁ
Table 1 shows a list of resistor selection for common
input voltages:
ꢁ
ꢃ
ꢈꢊ VIꢁꢂVOUT ꢅ
ꢀ
Table 1 -- Resistor Selection for Common Input
Voltages
Where ΔI is the inductor ripple current.
VIN
R3
R4
Choose the inductor ripple current to be 30% of the
maximum load current. The maximum inductor
peak current is calculated from:
5V
100kΩ
100kΩ
100kΩ
NC
12V
16V
71.5kΩ
45.3kΩ
ꢇIꢈ
Iꢈ(MAXꢉꢀIꢈOAD
ꢆ
2
Setting Output Voltage
The external resistor divider is used to set the output
voltage. FR9701 feedback resistors are
Under light load conditions below 100mA, a larger
inductance is recommended for improving efficiency.
unconcerned of compensation and provide an easy
way to program output voltage. Table 2 shows a list
of resistor selection for common output voltages:
R1
VOUTꢀ0.805ꢅ 1ꢆ ꢀ V
R2
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Application Information (Continued)
Selecting the Input Capacitor
PCB Layout Recommendation
The device’s performance and stability are
dramatically affected by PCB layout. It is
recommended to follow these general guidelines
shown as below:
The input capacitor reduces the surge current drawn
from the input supply and the switching noise from
the device. The input capacitor impedance at the
switching frequency should be less than the input
source impedance to prevent high frequency
switching current from passing through the input.
Ceramic capacitors with X5R or X7R dielectrics are
highly recommended because of their low ESR and
1. Place the input capacitors and output capacitors
as close to the device as possible. The traces
which connect to these capacitors should be as
short and wide as possible to minimize parasitic
inductance and resistance.
small
temperature
coefficients.
For
most
applications, a 10μF capacitor is sufficient.
2. Place VIN capacitors close to the VIN pin.
Selecting the Output Capacitor
3. Place feedback resistors close to the FB pin.
The output capacitor keeps the output voltage ripple
small, and a 47μF ceramic capacitor with X5R or
X7R dielectrics is recommended for its low ESR
characteristics.
4. Keep the sensitive signal (FB) away from the
switching signal (SW).
VIN
External Bootstrap Diode
SW
L1
VOUT
C2
An external bootstrap diode is recommended if the
input voltage is less than 5V or if there is a 5V system
C1
6
1
5
4
D1
rail available.
This diode helps improving the
efficiency. Low cost diodes, such as 1N4148, are
suitable for this application.
GND
D2
1N4148
2
3
R2
R1
VIN
5V
VIN
BS
Figure 17. FR9701 Recommended Layout Diagram
FR9701
C3
SW
Rectifier Diode
Use a Schottky diode as the rectifier to conduct current
when the high-side power MOSFET is off. The
Schottky diode must have current rating higher than
the maximum output current and the reverse voltage
rating higher than the maximum input voltage.
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Outline Information
SOT-23-6 Package (Unit: mm)
DIMENSION IN MILLIMETER
SYMBOLS
UNIT
MIN
0.90
0.00
0.90
0.30
2.80
2.60
1.50
0.90
1.80
0.30
MAX
1.45
0.15
1.30
0.50
3.00
3.00
1.70
1.00
2.00
0.60
A
A1
A2
B
D
E
E1
e
e1
L
Note：Followed From JEDEC MO-178-C.
Carrier dimensions
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Outline Information
TSOT-23-6 Package (Unit: mm)
DIMENSION IN MILLIMETER
SYMBOLS
UNIT
MIN
0.70
0.00
0.70
0.30
2.80
2.60
1.50
0.90
1.80
0.30
MAX
1.10
0.10
1.00
0.50
3.00
3.00
1.70
1.00
2.00
0.60
A
A1
A2
B
D
E
E1
e
e1
L
Carrier dimensions
Life Support Policy
Fitipower’s products are not authorized for use as critical components in life support devices or other medical systems.
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