HT7463A/HT7463B 52V/600mA, 1.25MHz/550kHz Asynchronous

HT7463A/HT7463B
52V/600mA, 1.25MHz/550kHz
Asynchronous Step Down Converter
Features
General Description
• Wide Input Voltage Range 4.5V to 52V
The HT7463A/B is a current mode buck converter.
With a wide input range from 4.5V to 52V,
the HT7463A/B is suitable for a wide range of
applications such as power conditioning from
unregulated sources. Having a low internal switch
typical RDSON value of 0.9Ω, the device has a good
operating typical efficiency value of 85% and the
added advantage of reduced junction temperature.
The operating frequency is fixed at 1250/550kHz for
the HT7463A/HT7463B respectively. The HT7463A
allows the use of small external components while
still being able to have low output voltage ripple.
A soft-start function can be implemented using the
enable pin and by connecting an external RC circuit
allowing the user to tailor the soft-start time to a
specific application.
• 52V / 0.9Ω Internal Power MOSFET
• 600mA Peak Output Current
• Up to 90% Efficiency
• 1.25MHz (HT7463A) and 550kHz (HT7463B)
Fixed Operating Frequency
• Ultra Low Shutdown Current < 1µA
• Output Short Circuit Protection
• Thermal Shutdown Protection
• Package Type: SOT23-6
Applications
• Power Meters
• Distribution Power Systems
• Battery Chargers
• Pre-Regulator for Linear Regulators
Application Circuit
CB
0.1µF
L1
22µH/47µH *3
HT7463A/B
1
2
3
SW
GND
VIN
FB
EN 4
R2
6kΩ / ±1%
C3
0.1µF
D1
6
CB
VOUT=12V *1
5
C4
22µF *2
VIN
On/Off
Control
C1
0.1µF
C2
100µF
R1
84kΩ / ±1%
Note: *1. C4=330μF is recommended to achieve 1‰ output ripple requirement
*2. Set R1=84kΩ and R2=16kΩ for VOUT=5V application
*3. It’s recommended that L1=22μH for HT7463A and L1=47μH for HT7463B
Rev. 1.00
1
September 25, 2014
HT7463A/HT7463B
Block Diagram
VIN
EN
Regulator
UVLO
1.25MHz/550kHz
Oscillator
FB
OCP
VCC VREF
Current
Sense Amp.
CB
VCC
VREF
0.9Ω
Control
Logic
Current
Comparator
FB
SW
OTP
0.794V
Error Amp.
GND
PWM
Comparator
SS/OSP
Pin Assignment
SOT23-6
SW
VIN
EN
6
5
4
463X
2
CB
GND
3
FB
1
Top View
X means A(1.25MHz)/or B(550kHz)
Rev. 1.00
2
September 25, 2014
HT7463A/HT7463B
Pin Descpription
Pin Order
Name
Type
Pin Discpription
1
CB
I/O
SW FET gate bias voltage. Connect the boot capacitor between CB and SW
2
GND
G
Ground terminal
3
FB
I
Feedback pin: Set feedback voltage divider ratio with VOUT = VFB (1+(R1/R2))
4
EN
I
Logic level shutdown pin. Internal pull low resistor
5
VIN
P
Power supply
6
SW
O
Power FET output
Absolute Maximum Ratings
Parameter
Value
Unit
VIN and SW
-0.3 to +55
V
EN
-0.3 to (VIN+0.3)
V
CB above SW voltage
+5.5
V
FB
-0.3 to +5.0
V
Operating Temperature Range
-40 to +85
°C
Maximum Junction Temperature
+150
°C
Storage Temperature Range
-65 to +160
°C
Lead Temperature (Soldering 10sec)
+300
°C
Human Body Model
2000
V
Machine Model
200
V
Junction-to-Ambient Thermal Resistance, θJA
220
°C/W
Junction-to-Case Thermal Resistance, θJC
110
°C/W
ESD Susceptibility
Recommended Operating Range
Parameter
Value
Unit
VIN
4.5 to 52
V
SW and EN
Up to 52
V
Note that Absolute Maximum Ratings indicate limitations beyond which damage to the device may occur.
Recommended Operating Ratings indicate conditions for which the device is intended to be functional, but do not
guarantee specified performance limits.
Rev. 1.00
3
September 25, 2014
HT7463A/HT7463B
Electrical Characteristics
Symbol
Parameter
VIN=12V and Tj=+25°C, unless otherwise specified
Test Condition
Min
Typ
Max
Unit
Supply Voltage
VIN
Input Voltage
VIN
4.5
—
52
V
ICC
Quiescent Current
VEN=2.5V, VFB=1V
—
0.7
1
mA
IOFF
Shutdown Current
VEN=0V
—
0.1
1
μA
Buck Converter
Output Voltage*
VOUT
fSW
Switching Frequency
FFB
Fold-back Frequency
1.0
—
0.9×VIN
V
HT7463A, VFB=0.6V
—
1000
1250
1500
kHz
HT7463B, VFB=0.6V
440
550
660
kHz
HT7463A, VFB=0V
90
105
—
kHz
HT7463B, VFB=0V
90
105
—
kHz
HT7463A
—
90
—
%
HT7463B
—
95
—
%
ns
DMAX
Maximum Duty Cycle
TON(min)
Minimum ON-Time
—
100
—
RDS(on)
Switch-ON Resistance
VEN=2.5V
—
0.9
—
Ω
ISW(off)
SW Leakage Current
VEN=0V, VSW=0V, VIN=52V
—
0.1
1
μA
VFB
Feedback Voltage
4.5V ≤ VIN ≤ 52V
0.778
0.794
0.81
V
IFB(leak)
Feedback Leakage Current
VFB=3V
—
—
0.1
μA
IEN
EN Input Current
VLH
VHL
—
VEN=0V
—
0.1
—
μA
VEN=52V
—
16
—
μA
EN High Voltage Threshold
4.5V ≤ VIN ≤ 52V
—
—
2.3
V
EN Low Voltage Threshold
4.5V ≤ VIN ≤ 52V
0.9
—
—
V
Protections
VUVLO+
Input Supply Turn ON Level
UVLO+
—
—
4.2
V
VUVLO−
Input Supply Turn OFF Level
UVLO−
3.4
—
—
V
—
1
—
A
—
150
—
°C
—
125
—
°C
IOCP
Over Current Protection Threshold
TSHD
Thermal Shutdown Threshold
TREC
Thermal Recovery Temperature
—
OTP
—
Note: 1. MIN Output Voltage is restricted by Minimum ON-Time, 100ns.
2. MAX Output Voltage is restricted by Maximum Duty Cycle and Switch-ON Resistance.
Rev. 1.00
4
September 25, 2014
HT7463A/HT7463B
Typical Performance Characteristics
VIN=18V, VOUT=12.5V, L=15/22µH for HT7463A and L=33/47µH for HT7463B, TA=25°C, unless otherwise noted
Efficiency vs. Load (HT7463A, VOUT=12.5V)
Efficiency vs. Load (HT7463B, VOUT=12.5V)
Efficiency vs. Load (HT7463A, VOUT=5.7V)
Efficiency vs. Load (HT7463B, VOUT=5.7V)
Efficiency vs. Load (HT7463A, VOUT=3.3V)
Efficiency vs. Load (HT7463B, VOUT=3.3V)
12.640
12.590
12.590
12.540
12.540
Vout (V)
Vout (V)
12.640
12.490
12.440
12.440
15uH
22uH
12.390
1
5
10
50
33uH
47uH
12.390
12.340
12.340
80 125 200 300 400 500 600
Output Current (mA)
Load Regulation (HT7463A, VOUT=12.5V)
Rev. 1.00
12.490
1
5
10
50
80
125 200 300 400 500 600
Output Current (mA)
Load Regulation (HT7463B, VOUT=12.5V)
5
September 25, 2014
HT7463A/HT7463B
Typical Performance Characteristics (Continued)
VIN=18V, VOUT=12.5V, L=22µH for HT7463A and L=47µH for HT7463B, TA=25°C, unless otherwise noted
5.860
5.810
5.810
5.760
5.760
Vout (V)
Vout (V)
5.860
5.710
5.710
5.660
5.660
5.560
1
5
10
5.560
1
50 80 125 200 300 400 500 600
Output Current (mA)
10
50
80
125 200 300 400 500 600
Load Regulation (HT7463B, VOUT=5.7V)
3.330
3.320
3.320
3.310
3.310
Vout (V)
3.330
3.300
3.300
3.290
3.290
3.280
3.280
15uH
22uH
3.270
33uH
47uH
3.270
3.260
3.260
1
5
10
50 80 125 200 300 400 500 600
Output Current (mA)
1
Load Regulation (HT7463A, VOUT=3.3V)
5
10
50 80 125 200 300 400 500 600
Output Current (mA)
Load Regulation (HT7463B, VOUT=3.3V)
12.515
12.510
12.510
12.505
12.505
Vout (V)
Vout (V)
12.515
12.500
12.495
12.490
12.500
12.495
12.490
15uH
22uH
12.485
12.480
14
18
24
33uH
47uH
12.485
12.480
36
14
Vin (V)
18
24
36
Vin (V)
Line Regulation (HT7463A, VOUT=12.5V, IOUT=300mA)
Line Regulation (HT7463B, VOUT=12.5V, IOUT=300mA)
5.705
5.704
5.704
5.703
5.703
5.702
5.702
5.701
5.701
Vout (V)
Vout (V)
5.705
5.700
5.699
5.700
5.699
5.698
5.698
5.697
5.697
15uH
22uH
5.696
5.695
8
12
Vin (V)
18
33uH
47uH
5.696
5.695
24
8
Line Regulation (HT7463A, VOUT=5.7V, IOUT=300mA)
Rev. 1.00
5
Output Current (mA)
Load Regulation (HT7463A, VOUT=5.7V)
Vout (V)
33uH
47uH
5.610
15uH
22uH
5.610
12
Vin (V)
18
24
Line Regulation (HT7463B, VOUT=5.7V, IOUT=300mA)
6
September 25, 2014
3.315
3.315
3.314
3.314
3.313
3.313
3.312
3.312
3.311
3.311
Vout (V)
Vout (V)
HT7463A/HT7463B
3.310
3.310
3.309
3.309
3.308
3.308
15uH
22uH
3.307
3.306
3.307
8
12
18
33uH
47uH
3.306
3.305
3.305
24
8
Vin (V)
Line Regulation (HT7463A, VOUT=3.3V, IOUT=300mA)
1200
Frequency (KHz)
Current Limit (A)
24
1400
1
0.8
0.6
0.4
HT7463A
HT7463B
0.2
0
1000
800
600
400
HT7463A
HT7463B
200
0
1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8
0
VEN (V)
IOCP vs. VEN (HT7463A and HT7463B)
0.1
0.2
0.3
0.4
Vfb (V)
0.5
0.6
0.7
fSW vs. VFB (HT7463A and HT7463B)
1600
1600
1400
1200
1200
Frequency (KHz)
1400
1000
OCP (mA)
18
Vin (V)
Line Regulation (HT7463B, VOUT=3.3V, IOUT=300mA)
1.2
800
600
400
HT7463A
HT7463B
200
0
-40
-20
0
25
50
Temperature (℃)
85
100
1000
800
600
400
HT7463A
HT7463B
200
0
-40
125
IOCP vs. TEMP (HT7463A and HT7463B)
-20
0
25
50
Temperature (℃)
85
100
125
fSW vs. TEMP (HT7463A and HT7463B)
1
0.805
0.9
0.8
Quiescent (mA)
0.8
0.795
VFB (V)
12
0.79
0.785
0.78
-40
-20
0
25
50
Temperature (℃)
85
100
0.5
0.4
0.3
HT7463A
HT7463B
0.1
0
125
-40
VFB vs. TEMP (HT7463A and HT7463B)
Rev. 1.00
0.6
0.2
HT7463A
HT7463B
0.775
0.7
-20
0
25
50
Temperature (℃)
85
100
125
ICC vs. TEMP (HT7463A and HT7463B)
7
September 25, 2014
HT7463A/HT7463B
Output Ripple (HT7463A, IOUT=400mA)
Output Ripple (HT7463B, IOUT=400mA)
Output Ripple (HT7463A, IOUT=125mA)
Output Ripple (HT7463B, IOUT=125mA)
Load Transient (HT7463A, IOUT=50mA to 200mA)
Load Transient (HT7463B, IOUT=50mA to 200mA)
Power Up (HT7463A, VIN=52V, IOUT=500mA)
Power Up (HT7463B, VIN=52V, IOUT=500mA)
Rev. 1.00
8
September 25, 2014
HT7463A/HT7463B
Power Down (HT7463A, VIN=52V, IOUT=500mA)
Power Down (HT7463B, VIN=52V, IOUT=500mA)
Output Short (HT7463A, IOUT=500mA)
Output Short (HT7463B, IOUT=500mA)
Short Recovery (HT7463A, IOUT=500mA)
Short Recovery (HT7463B, IOUT=500mA)
Enable ON (HT7463A, IOUT=500mA)
Enable ON (HT7463B, IOUT=500mA)
Rev. 1.00
9
September 25, 2014
HT7463A/HT7463B
Enable OFF (HT7463A, IOUT=500mA)
Enable OFF (HT7463B, IOUT=500mA)
Functional Description
Output Voltage Setup
Protection Features
The external resistor divider sets the output voltage,
for details see the Application Circuit. The feedback
resistor, R1, also sets the feedback loop bandwidth
with the internal compensation capacitor. An R1
value of greater than 80KΩ is recommended. R2 is
calculated using the following equation:
The devices include dedicated protection circuitry which
is fully active during normal operation for full device
protection. The thermal shutdown circuitry turns off
power to the device when the die temperature reaches
excessive levels. The UVLO comparator protects
the power device during supply power startup and
shutdown to prevent operation at voltages less than the
minimum input voltage. The HT7463A/B also features
a shutdown mode decreasing the supply current to
approximately 0.1μA.
R2=R1/((VOUT/0.794V)-1) Ω
Rev. 1.00
10
September 25, 2014
HT7463A/HT7463B
Recommended Component Values
CB
0.1µF
L1
22µH/47µH *
HT7463A/B
1
2
3
C3
0.1µF
D1
6
CB
SW
GND
VIN
FB
EN 4
VOUT
5
C4
22µF
VIN
On/Off
Control
C1
0.1µF
C2
100µF
R1
CC
R2
0.1uF
(Optional)
Note: * It’s recommended that L1=22μH for HT7463A and L1=47μH for HT7463B.
Rev. 1.00
VOUT (V)
R1 (kΩ)
R2 (kΩ)
1.8
80 (1%)
64 (1%)
2.5
102 (1%)
48 (1%)
3.3
125 (1%)
40 (1%)
5.0
84 (1%)
16 (1%)
12
84 (1%)
6 (1%)
11
September 25, 2014
HT7463A/HT7463B
Component Selection Guide
Frequency Fold-back Function
The devices include a frequency fold-back function
to prevent situations of over current when the output
is shorted. It efficiently reduces overheating even if
the output is shorted. This function is implemented
by changing the switching frequency according
the feedback voltage, V FB. When the output node
is shorted, the device will reduce the frequency to
105kHz for the HT7463A/HT7463B respectively
resulting in a clamped input current. The HT7463A/
HT7463B operates at a frequency of 1250/550kHz
under normal conditions and the feedback voltage is
about 0.794V.
1400
Use an inductor with a DC current rating at least 25%
percent higher than the maximum load current for
most applications. The DC resistance of the inductor
is a key parameter affecting efficiency. With regard to
efficiency, the inductor’s DC resistance should be less
than 200mΩ. For most application, the inductor value
can be calculated from the following equation.
L=
1000
800
600
400
Input Capacitor
HT7463A
HT7463B
200
0
0
0.1
0.2
0.3
0.4
0.5
0.6
A low ESR ceramic capacitor (CIN) is needed between
the VIN pin and GND pin. Use ceramic capacitors
with X5R or X7R dielectrics for their low ESRs and
small temperature coefficients. For most applications,
a 2.2μF- 10µF capacitor will suffice.
0.7
VFB (V)
Start-up Function
The device EN pin in conjunction with an RC filter is
used to tailor the soft-start time to specific application
requirements. When a voltage applied to the EN pin
is between 0V and 2.3V, the device will cause the
cycle-by-cycle current limit in the power stage to be
modulated for a minimum current limit at 0V up to a
the rated current limit at 2.3V. Thus, the output rise
time and inrush current at startup are controlled.
1.2
Current Limit (A)
1
Vout × (VIN − Vout )
VIN × Iripple × fsw
A higher value of ripple current reduces the inductance
value, but increases the conductance loss, core loss,
and current stress for the inductor and switch devices.
A suggested choice is for the inductor ripple current to
be 30% of the maximum load current.
FREQUENCY FOLD-BACK
1200
Frequency (KHz)
Inductor
Output Capacitor
The selection of COUT is driven by the maximum allowable output voltage ripple. Use ceramic capacitors with
X5R or X7R dielectrics for their low ESR characteristics.
Capacitors in the range of 22μF to 100μF are a good
starting point with an ESR of 0.1Ω or less.
Schottky Diode
VEN vs. Current Limit
The breakdown voltage rating of the diode should be
higher than the maximum input voltage. The current
rating for the diode should be equal to the maximum
output current to ensure the best reliability in most
applications. In this case it is possible to use a diode
with a lower average current rating, however the peak
current rating should be higher than the maximum
load current.
0.8
0.6
0.4
HT7463A
HT7463B
0.2
0
1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8
Bootstrap Capacitor
VEN (V)
A 0.1μF ceramic capacitor or larger is recommended
for the bootstrap capacitor. Generally a 0.1μF to 1μF
value can be used to ensure sufficient gate drive for
the internal switches and a consistently low RDSON.
Rev. 1.00
12
September 25, 2014
HT7463A/HT7463B
Layout Consideration Guide
Thermal Considerations
To reduce problems with conducted noise, there are
some important points to consider regarding the PCB
layout.
The maximum power dissipation depends on the
thermal resistance of the IC package, the PCB layout,
the rate of the surrounding airflow and the difference
between the junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula:
• Ensure all feedback connections are short and direct.
Place the feedback resistors and compensation
components as close to the FB pin as possible.
PD(MAX) = (TJ(MAX) – TA) / θJA
• The input bypass capacitor must be placed close to
the VIN pin.
where TJ(MAX) is the maximum junction temperature,
TA is the ambient temperature and qJA is the junctionto-ambient thermal resistance of the IC package
(220oC/W for SOT23-6)
• The inductor, schottky diode and output capacitor
trace should be as short as possible to reduce
conducted and radiated noise and increase overall
efficiency.
For maximum operating rating conditions, the
maximum junction temperature is 150oC. However, it is
recommended that the maximum junction temperature
does not exceed 125oC in normal operation to maintain
reliability. The derating curve for maximum power
dissipation is as follows:
• Keep the power ground connection as short and
wide as possible.
Maximum Power
Dissipation (W)
0.6
0.568W
0.5
0.4
0.3
0.2
0.1
0
0
25
50
75
100
125
150
Ambient Temperature (oC)
Rev. 1.00
13
September 25, 2014
HT7463A/HT7463B
Package Information
Note that the package information provided here is for consultation purposes only. As this information may be
updated at regular intervals users are reminded to consult the Holtek website for the latest version of the package
information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant section to be
transferred to the relevant website page.
• Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• Packing Meterials Information
• Carton information
Rev. 1.00
14
September 25, 2014
HT7463A/HT7463B
SOT23-6 Outline Dimensions
Symbol
A
Min.
Nom.
Max.
—
—
0.057
A1
—
—
0.006
A2
0.035
0.045
0.051
b
0.012
—
0.020
C
0.003
—
0.009
D
—
0.114 BSC
—
E
—
0.063 BSC
—
e
—
0.037 BSC
—
e1
—
0.075 BSC
—
H
—
0.110 BSC
—
L1
—
0.024 BSC
—
θ
0°
—
8°
Symbol
Rev. 1.00
Dimensions in inch
Dimensions in mm
Min.
Nom.
Max.
A
—
—
1.45
A1
—
—
0.15
A2
0.90
1.15
1.30
b
0.30
—
0.50
C
0.08
—
0.22
D
—
2.90 BSC
—
E
—
1.60 BSC
—
e
—
0.95 BSC
—
e1
—
1.90 BSC
—
H
—
2.80 BSC
—
L1
—
0.60 BSC
—
θ
0°
—
8°
15
September 25, 2014
HT7463A/HT7463B
Copyright© 2014 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time
of publication. However, Holtek assumes no responsibility arising from the use of
the specifications described. The applications mentioned herein are used solely
for the purpose of illustration and Holtek makes no warranty or representation that
such applications will be suitable without further modification, nor recommends
the use of its products for application that may present a risk to human life due to
malfunction or otherwise. Holtek's products are not authorized for use as critical
components in life support devices or systems. Holtek reserves the right to alter
its products without prior notification. For the most up-to-date information, please
visit our web site at http://www.holtek.com.tw.
Rev. 1.00
16
September 25, 2014