HT77xxBA
5V/200mA PFM
Asynchronous Step-up Converter
Features
General Description
• Low startup voltage: 0.85V (Typical)
The HT77xxBA series is a set of PFM step-up DC/DC
converters with high efficiency and low ripple. The
series features extremely low start-up voltage and
high output voltage accuracy. They require only
few external components to provide a fixed output
voltage of 2.7V, 3.0V, 3.3V, 3.7V and 5.0V. CMOS
technology ensures low supply current and makes
them ideal for battery-operated applications powered
from one or more cells.
• High efficiency up to 85%
• Ultra low no load input current
• High output voltage accuracy: ±2.5%
• Fixed output voltage: 2.7V, 3.0V, 3.3V, 3.7V and
5.0V
• Ultra low shutdown current: 0.1μA (Typical)
• Package type: 3-pin SOT89, 3-pin SOT23 and
5-pin SOT23
The HT77xxBA series consist of an oscillator, a PFM
control circuit, a driver transistor, a reference voltage
unit and a high speed comparator. They employ
pulse frequency modulation (PFM) for minimum
supply current and ripple at light output loading.
These devices are available in space saving 3-pin
SOT89, 3-pin SOT23 and 5-pin SOT23 packages.
For the 5-pin SOT23 package, it also contains a chip
enable function to reduce power consumption during
shutdown mode.
Applications
• One, two and three cell alkaline and NiMH/NiCd
bettery powered portable products
• Portable equipment/handheld devices
Typical Application Circuits
D1: 1N5817
L1: 47μH~100μH
(Coil Inductor)
VIN
LX
VOUT
OUT
HT77xxBA
C1: 47μF
OFF ON
CE
GND
R1*
C2: 22μF
(Ceramic)
* R1=0.15Ω is recommended to improve ripple performance
Selection Table
Part No.
Output Voltage
HT7727BA
2.7V
HT7730BA
3.0V
HT7733BA
3.3V
HT7737BA
3.7V
HT7750BA
5.0V
Packages
Markings
SOT89
SOT23
SOT23-5
77xxBA marking for SOT89 type
xxBA marking for SOT23 and SOT23-5 types
Note: ″xx″ stands for output voltages.
Rev. 1.20
1
September 13, 2018
HT77xxBA
Block Diagram
OUT
VREF
LX
LX Limiter
200kHz OSC
Buffer
PFM Control
GND
Chip Enable
CE
Pin Assignment
SOT23
SOT89
SOT23-5
OUT
LX
GND
3
5
4
xxBA
77xxBA
xxBA
1
2
1
2
GND
LX
CE
OUT
3
NC
1
2
3
GND
OUT
LX
Pin Description
Pin No.
Pin Name
SOT89
SOT23
SOT23-5
—
—
1
CE
2
3
2
OUT
—
—
3
NC
1
1
4
GND
3
2
5
LX
Rev. 1.20
2
Pin Description
Chip enable pin, high active.
Output voltage pin
No connection
Ground pin
Switching pin
September 13, 2018
HT77xxBA
Absolute Maximum Ratings
Parameter
Value
Unit
OUT
-0.3 to +6.0
V
LX and CE
-0.3 to +6.0
V
+150
˚C
-65 to +150
˚C
+260
˚C
Human Body Mode
5000
V
Machine Mode
400
V
Maximum Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering 10sec)
ESD Susceptibility
Junction-to-Ambient Thermal Resistance, θJA
Power Dissipation, PD
SOT89
200
SOT23
500
SOT23-5
500
SOT89
0.625
SOT23
0.25
SOT23-5
0.25
˚C/W
W
Recommended Operating Ratings
Parameter
VIN
Operating Temperature Range
Value
Unit
0.85 to 5
V
-40 to +85
˚C
Note that Absolute Maximum Ratings indicate limitations beyond which damage to the device may occur.
Recommended Operating Ratings indicate conditions for which the devices are intended to be functional, but do
not guarantee specified performance limits.
Rev. 1.20
3
September 13, 2018
HT77xxBA
Electrical Characteristics
VIN=0.6×VOUT, IOUT=10mA and Ta=25˚C, unless otherwise specified
Symbol
Parameter
Test Condition
Min. Typ. Max. Unit
VIN
Input Voltage Range
—
—
—
5.5
V
∆VOUT
Output Voltage Accuracy
—
-2.5
—
+2.5
%
VST
Startup Voltage (Fig.1)
VIN: 0V → 2V, IOUT=1mA
—
0.85
1
V
VHOLD
Hold on Voltage (Fig.1)
VIN: 2V → 0V, IOUT=1mA
—
—
0.7
V
IIN
No Load Input Current (Fig.1)
IOUT=0mA
8
10
20
μA
IDD
Non-switching Current (Fig.2)
VDD=VOUT+0.5V, VX=floating
—
5
10
μA
ISHDN
Shutdown Current (Fig.1)
CE=GND
—
0.1
1
μA
—
0.39
—
—
RDS(ON)
IOCP
On Resistance (Fig.3)
Over Current Protection Threshold
VDD=2.6V, ILX=300mA
VOUT=2.7V
VDD=2.9V, ILX=300mA
VOUT=3.0V
—
0.38
VDD=3.2V, ILX=300mA
VOUT=3.3V
—
0.37
—
VDD=3.6V, ILX=300mA
VOUT=3.7V
—
0.35
—
VDD=4.85V, ILX=300mA
VOUT=5.0V
—
0.33
—
VOUT=2.7V
—
1.0
—
VOUT=3.0V
—
1.0
—
VOUT=3.3V
—
1.1
—
VOUT=3.7V
—
1.1
—
VOUT=5.0V
Ω
A
—
1.6
—
—
1.6
—
—
—
—
—
0.4
V
—
—
1
μA
Maximum Oscillator Frequency (Fig.2) VDD=0.9×VOUT, VX=5.5V, measured at LX pin
—
200
—
kHz
Oscillator Duty Cycle (Fig.2)
VDD=0.9×VOUT, VX=5.5V, measured at LX pin
65
75
85
%
—
—
85
—
%
VIH
CE High Threshold
VIL
CE Low Threshold
ILEAK
LX Leakage Current (Fig.2)
fOSC
DOSC
η
Efficiency
VDD=VX=VOUT+0.5V, measured at LX pin
V
Note: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating
Ratings indicate conditions for which the devices are intended to be functional, but do not guarantee specific
performance limits. The guaranteed specifications apply only for the test conditions listed.
D1: 1N5817
IIN
L1: 47μH
(Coil Inductor)
VIN
LX
OUT
VOUT
HT77xxBA
C1: 47μF
(Ceramic)
GND
C2: 22μF
(Ceramic)
CE
Fig.1
VX
IX
1kΩ
IDD
LX
OUT
IDD
HT77xxBA
GND
Rev. 1.20
LX
VDD
ILX
CE
Fig. 2
OUT
VDD
HT77xxBA
GND
CE
Fig. 3
4
September 13, 2018
HT77xxBA
Typical Performance Characteristics
VIN=0.6×VOUT, CIN=47µF, COUT=22µF, L=47µH, Ta=25˚C, unless otherwise specified
HT7733BA Efficiency vs. Output Current
HT7750BA Efficiency vs. Output Current
HT7733BA IDD vs. Ta
HT7750BA IDD vs. Ta
HT7733BA Startup/Hold-on Voltage
HT7750BA Startup/Hold-on Voltage
RON vs. VDD
Rev. 1.20
5
September 13, 2018
HT77xxBA
VIN=0.6×VOUT, CIN=47µF, COUT=22µF, L=47µH, Ta=25˚C, unless otherwise specified
HT7733BA Load Transient (1mA to 50mA)
HT7750BA Load Transient (1mA to 50mA)
HT7733BA Load Transient (1mA to 200mA)
HT7750BA Load Transient (1mA to 200mA)
HT7733BA Line Transient (1V~2V, IOUT=50mA)
HT7750BA Line Transient (1V~2V, IOUT=50mA)
HT7733BA Power On/Off (IOUT=50mA)
HT7750BA Power On/Off (IOUT=50mA)
Rev. 1.20
6
September 13, 2018
HT77xxBA
VIN=0.6×VOUT, CIN=47µF, COUT=22µF, L=47µH, Ta=25˚C, unless otherwise specified
HT7733BA Operation (IOUT=0mA)
HT7750BA Operation (IOUT=0mA)
HT7733BA Operation (IOUT=100mA)
HT7750BA Operation (IOUT=100mA)
HT7733BA Chip Enable/Disable
HT7750BA Chip Enable/Disable
Rev. 1.20
7
September 13, 2018
HT77xxBA
Component Selection
PCB Layout Suggestion
Power Inductor
To reduce problems with conducted noise, there are
some important points to note on the PCB layout.
It is recommended to use a 47μH or higher inductance
to remain low output ripple voltage in most
applications. Increasing the inductance will result in
lower output ripple voltage. It is suggested to choose a
lower DCR with a typical value less than 1Ω to reduce
the efficiency loss. Otherwise, the chosen inductor
saturation current should be greater than its peak current
with a typical value of 1A or higher in applications.
• The input bypass capacitor must be placed close to
the VIN pin.
• The inductor, schottky diode and output capacitor
trace should be as short as possible to reduce the
conducted and radiated noise and increase overall
efficiency.
Schottky Diode
The diode breakdown voltage rating should be higher
than the maximum output voltage. The diode current
rating equal to or greater than 1A is suggested.
Input Capacitor
A low ESR ceramic capacitor, CIN, is needed between
the VIN and GND pins. Use ceramic capacitors with
X5R or X7R dielectrics for their low ESRs and small
temperature coefficients. For most applications, a
47µF capacitor will be a proper selection.
SOT23/SOT23-5 PCB Layout Example
Output Capacitor
The output capacitor, COUT, selection is determined
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. It is usually suggested to use a
22μF capacitor in most applications.
Ripple Improved Resistor with a No Load
Condition
It is strongly recommended to add a ripple improved
resistor, R1, to keep the switching stability with a no
load condition. It is recommended to set R1 to 0.15Ω.
Note that this extra resistor improves the ripple
performance under no load conditions, but induces
higher ripple voltage when the load is heavy.
SOT89 PCB Layout Example
D1: 1N5817
L1: 47μH~100μH
(Coil Inductor)
VIN
LX
OUT
HT77xxBA
C1: 47μF
OFF ON
CE
GND
VOUT
R1*
C2: 22μF
(Ceramic)
* R1=0.15Ω is recommended to improve ripple performance
Rev. 1.20
8
September 13, 2018
HT77xxBA
Thermal Consideration
For maximum operating rating conditions, the
maximum junction temperature is 150˚C. However,
it’s recommended that the maximum junction
temperature does not exceed 125˚C during normal
operation to maintain high reliability. The de-rating
curve of the maximum power dissipation is show
below:
The maximum power dissipation depends upon the
thermal resistance of the IC package, PCB layout,
rate of surrounding airflow and difference between
the junction and ambient temperature. The maximum
power dissipation can be calculated by the following
formula:
PD(MAX) = (150˚C – 25˚C) / (500˚C/W) = 0.25W
PD(MAX) = (TJ(MAX) – Ta) / θJA......................(W)
For a fixed TJ(MAX) of 150˚C, the maximum power dissipation depends upon the operating ambient temperature and the package’s thermal resistance, θJA. The derating curve below shows the effect of rising ambient
temperature on the maximum recommended power
dissipation.
Maximum Power Dissipation (W)
Where TJ(MAX) is the maximum junction temperature,
Ta is the ambient temperature and θJA is the junction
to ambient thermal resistance.
1.0
0.8
SOT89
0.625
0.4
SOT23
SOT23-5
0.25
0
0
25
50
75
85
100
125
150
o
Ambient Temperature ( C)
Rev. 1.20
9
September 13, 2018
HT77xxBA
Application Circuits
Without CE Pin Application Circuits
D1: 1N5817
L1: 47μH~100μH
(Coil Inductor)
VIN
LX
OUT
VOUT
HT77xxBA
C1: 47μF
R1*
GND
C2: 22μF
(Ceramic)
* R1=0.15Ω is recommended to improve ripple performance
With CE Pin Application Circuits
D1: 1N5817
VIN
L1: 47μH~100μH
(Coil Inductor)
LX
OUT
VOUT
HT77xxBA
C1: 47μF
OFF ON
R1*
CE
GND
C2: 22μF
(Ceramic)
* R1=0.15Ω is recommended to improve ripple performance
Note: 1. When CE=‘0’, the device internal circuits such as the bandgap reference, gain block and all feedback and
control circuitry will be switched off.
2. When CE=‘0’, the output voltage, VOUT, is almost equal to VIN.
3. If the CE pin is not used, it should be externally connected to the OUT pin.
Rev. 1.20
10
September 13, 2018
HT77xxBA
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. 1.20
11
September 13, 2018
HT77xxBA
3-pin SOT23 Outline Dimensions
Symbol
Nom.
Max.
A
—
—
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. 1.20
Dimensions in inch
Min.
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°
12
September 13, 2018
HT77xxBA
5-pin SOT23 Outline Dimensions
H
Symbol
Min.
Nom.
Max.
A
—
—
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
A
Rev. 1.20
Dimensions in inch
Dimensions in mm
Min.
Nom.
Max.
—
—
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°
13
September 13, 2018
HT77xxBA
3-pin SOT89 Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
0.173
—
0.185
B
0.053
—
0.072
C
0.090
—
0.106
D
0.031
—
0.047
E
0.155
—
0.173
F
0.014
—
0.019
G
0.017
—
0.022
H
—
0.059 BSC
—
I
0.055
—
0.063
J
0.014
—
0.017
Symbol
Rev. 1.20
Dimensions in mm
Min.
Nom.
Max.
A
4.40
—
4.70
B
1.35
—
1.83
C
2.29
—
2.70
D
0.80
—
1.20
E
3.94
—
4.40
F
0.36
—
0.48
G
0.44
—
0.56
H
—
1.50 BSC
—
I
1.40
—
1.60
J
0.35
—
0.44
14
September 13, 2018
HT77xxBA
Copyright© 2018 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.
Rev. 1.20
15
September 13, 2018