200mA PFM Synchronous Step-up DC/DC Converter

HT77xxSA
200mA PFM Synchronous
Step-up DC/DC Converter
Features
General Description
• Low start-up voltage: 0.7V (Typ.)
The HT77xxSA devices are a high efficiency PFM
synchronous step-up DC-DC converter series which
are designed to operate with both wire wound chip
power inductors and also with multi-layered chip
power inductors. The device series have the advantages of extremely low start-up voltage as well as high
output voltage accuracy. Being manufactured using
CMOS technology ensures ultra low supply current.
Because of their higher operating frequency, up to 500
kHz, the devices have the benefits of requiring smaller
outline type lower value external inductors and capacitors. The higher operating frequency also offers the
advantages of much reduced audio frequency noise.
The devices require only three external components to
provide a fixed output voltage of 2.7V, 3.0V, 3.3V or
5.0V.
• High efficiency: 2.7V ≤ VOUT ≤ 5.0V upper 90%
(Typ.)
• High output voltage accuracy: ±2.5%
• Output voltage: 2.7V, 3.0V, 3.3V, 5.0V
• Output current up to 200mA
• Ultra low supply current IDD: 5μA (Typ.)
• Low ripple and low noise
• Low shutdown current: 0.1μA (Typ.)
• TO92, SOT89, SOT23 and SOT23-5 package
Applications
• Palmtops/PDAs
The HT77xxSA devices include an internal oscillator,
PFM control circuit, driver transistor, reference voltage unit and a high speed comparator. They employ
pulse frequency modulation techniques, to obtain
minimum supply current and ripple at light output
loading. These devices are available in space saving
TO92, SOT89, SOT23 and SOT23-5 packages. For
SOT23-5 package types, they also include an internal
chip enable function to reduce power consumption
when in the shutdown mode.
• Portable communicators/Smartphones
• Cameras/Camcorders
• Battery-powered equipment
Selection Table
Part No.
Output Voltage
HT7727SA
2.7V
HT7730SA
3.0V
HT7733SA
3.3V
HT7750SA
5.0V
Tolerance
Package
±2.5%
TO92
SOT89
SOT23
SOT23-5
Block Diagram
V O U T
L X
L X L im ite r
L X
B u ffe r
V re f
O S C
P F M
V O U T
C o n tro l
C h ip E n a b le
G N D
C E
Rev. 1.00
1
October 04, 2012
HT77xxSA
Pin Assignment
V O U T
3
F r o n t V ie w
1
2
L X
5
G N D
4
3
T o p V ie w
T o p V ie w
G N D V O U T L X
B o tto m
1
2
3
G N D
V O U T
L X
G N D
V O U T
L X
1
2
1
2
3
G N D
L X
C E
V O U T
N C
G N D
L X
C E
V O U T
N C
V ie w
Pin Description
Pin No.
Pin Name
TO92
SOT89
SOT23
SOT23-5
—
—
—
1
CE
2
2
3
2
VOUT
—
—
—
3
NC
1
1
1
4
GND
3
3
2
5
LX
Description
Chip enable pin, high active
DC/DC converter output monitoring pin
No connection
Ground pin
Switching pin
Absolute Maximum Ratings
Maximum Input Supply Voltage........................... 6.5V
Storage Temperature ........................... -50°C to 125°C
Ambient Temperature Range ................ -40°C to 85°C
Note: These are stress ratings only. Stresses exceeding the range specified under "Absolute Maximum Ratings"
may cause substantial damage to the device. Functional operation of this device at other conditions beyond
those listed in the specification is not implied and prolonged exposure to extreme conditions may affect
device reliability.
Rev. 1.00
2
October 04, 2012
HT77xxSA
Electrical Characteristics
Symbol
Ta= 25°C; VIN= VOUT×0.6; IOUT= 10mA; unless otherwise specified
Parameter
VIN
Input Voltage
Test Conditions
—
Min.
Typ.
Max.
Unit
—
—
6.0
V
ΔVOUT
Output Voltage Tolerance
-2.5
—
+2.5
%
VSTART
Starting Voltage(Fig.1)
VIN : 0 to 2V, IOUT=1mA
—
0.7
0.9
V
VHOLD
Voltage Hold(Fig.1)
VIN : 2 to 0V, IOUT=1mA
—
—
0.7
V
IDD1
Supply Current (Fig.2)
VS=VOUT+0.5V,
Measured at VOUT Pin
—
5.0
—
μA
IDD2
Un-load Supply Current (Fig.1)
VIN=VOUT×0.6, IOUT=0mA
Measurement at LX
—
—
μA
ISHDN
Shutdown Current
CE=GND
ILimit
Current Limit (Fig.1)
VIH
CE High Threshold
VIL
CE Low Threshold
—
0.1
—
μA
VOUT ≤ 5.0V
650
800
—
mA
2.7V ≤ VOUT ≤ 3.3V
500
650
—
mA
2.0
—
—
V
—
—
0.4
V
—
0.05
—
μA
—
500
—
kHz
—
ILEAK
LX Leakage Current (Fig.3)
fOSC
Oscillator Frequency (Fig.3)
VS=5.5V, VX=4V
Measurement at the LX pin
DOSC
Oscillator Duty Cycle (Fig.3)
VS=VOUT×0.95
Measurement at the LX pin
η
Efficiency
2.7V ≤ VOUT ≤ 5.0V, IOUT=10mA
—
80
—
%
—
90
—
%
Note: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating
Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific
performance limits. The guaranteed specifications apply only for the test conditions listed.
L
VIN
10uH
LX
VOUT
VOUT
HT77xxSA
CIN
10uF
COUT
10uF
GND
L: ABC SR0503 10uH
CIN=COUT: muRata 10uF
Fig.1
VOUT
LX
LX
VS
HT77xxSA
VOUT
VS
HT77xxSA
100
GND
GND
VX
Fig.2
Rev. 1.00
Fig.3
3
October 04, 2012
HT77xxSA
Application Circuits
Without CE Pin
VIN
L
10μH
LX
VOUT
VOUT
HT77xxSA
CIN
10μF
COUT
10μF
GND
With CE Pin
VIN
L
10μH
CIN
10μF
VIN
VOUT
Rev. 1.00
CE
COUT
10μF
GND
VOUT
LX
CE
VOUT
HT77xxSA
L
10μH
CIN
10μF
VOUT
LX
VOUT
HT77xxSA
GND
4
COUT
10μF
October 04, 2012
HT77xxSA
Functional Description
Application Information
The HT77xxSA is a constant on time synchronous stepup converter, which uses a pulse frequency modulation
(PFM) controller scheme. The PFM control scheme is
inherently stable. The required input/output capacitor
and inductor selections will not create situations of
instability.
Inductor Selection
Selecting a suitable inductor is an important consideration as it is usually a compromise situation between
the output current requirements, the inductor saturation
limit and the acceptable output voltage ripple. Lower
values of inductor values can provide higher output
currents but will suffer from higher ripple voltages
and reduced efficiencies. Higher inductor values can
provide reduced output ripple voltages and better efficiencies, but will be limited in their output current
capabilities. For all inductors it must be noted however
that lower core losses and lower DC resistance values
will always provide higher efficiencies.
The device includes a fully integrated synchronous
rectifier which reduces costs (includes reduce L and C
sizes, eliminates Schottky diode cost etc.) and board
area. A true load disconnect function ensures that the
device is completely shutdown.
Low Voltage Start-up
The devices have a very low start up voltage down to
0.7V. When power is first applied, the synchronous
switch will be initially off but energy will be transferred to the load through its intrinsic body diode.
The peak inductor current can be calculated using the
following equation:
I L ( PEAK ) =
Shutdown
Where
During normal device operation, the EN pin should be
either high or connected to the VOUT pin or the VIN
power source. When the device is in the shutdown
mode, that is when the EN pin is pulled low, the internal circuitry will be switched off. During shutdown,
the PMOS power transistor will be switched off thus
placing the output into a floating condition.
VIN = Input Voltage
VOUT = Output Voltage
IO = Output Current
η = Efficiency
L = Inductor
Capacitor Selection
Synchronous Rectification
As the output capacitor selected affects both efficiency and output ripple voltage, it must be chosen with
care to achieve best results from the converter. Output
voltage ripple is the product of the peak inductor current
and the output capacitor equivalent series resistance
or ESR for short. It is important that low ESR value
capacitors are used to achieve optimum performance.
One method to achieve low ESR values is to connect
two or more filter capacitors in parallel. The capacitors
values and rated voltages are only suggested values.
A dead time exists between the N channel and P channel MOSFET switching operations. In synchronous
rectification, the P channel is replaced by a Schottky
diode. Here the P channel switch must be completely
off before the N channel switch is switched on. After
each cycle, a 30ns delay time is inserted to ensure the
N channel switch is completely off before the P channel
switch is switched on to maintain a high efficiency
over a wide input voltage and output power range.
Rev. 1.00
VOUT × IO VIN × (VOUT − VIN )
+
VIN × η
2 × VOUT × L
5
October 04, 2012
HT77xxSA
Layout Considerations
• All tracks should be as wide as possible.
• The input and output capacitors should be placed
as close as possible to the VIN, VOUT and GND
pins.
Circuit board layout is a very important consideration
for switching regulators if they are to function properly.
• A full ground plane is always helpful for better
EMI performance.
Poor circuit layout may result in related noise problems. In order to minimise EMI and switching noise,
note the following guidelines:
Rev. 1.00
Top Layer
Bottom Layer
Top Layer
Bottom Layer
Top Layer
Bottom Layer
Top Layer
Bottom Layer
6
October 04, 2012
HT77xxSA
Typical Performance Characteristics
HT7750SA
Fig 4. Ripple Voltage vs. Output Current
Fig 1. Output Voltage vs. Output Current
Fig 2. Efficiency vs. Output Current
Fig 5. Load Transient Response
(L=10mH, CIN=COUT=10mF, VIN=3.0V)
Fig 3. Start-up & Hold-on Voltage
Fig 6. Line Transient Response
(L=10mH, CIN=COUT=10mF, VIN=3.0V)
Rev. 1.00
7
October 04, 2012
HT77xxSA
HT7733SA
Fig 7. Output Voltage vs. Output Current0%
Fig 10. Ripple Voltage vs. Output Current
Fig 8. Efficiency vs. Output Current
Fig 11. Load Transient Response
(L=10mH, CIN=COUT=10mF, VIN=1.98V)
Fig 9. Start-up & Hold-on Voltage
Fig 12. Line Transient Response
(L=10mH, CIN=COUT=10mF, VIN=1.98V)
Rev. 1.00
8
October 04, 2012
HT77xxSA
HT7730SA
Fig 13. Output Voltage vs. Output Current
Fig 16. Ripple Voltage vs. Output Current
Fig 14. Efficiency vs. Output Current
Fig 17. Load Transient Response
(L=10mH, CIN=COUT=10mF, VIN=1.8V)
Fig 15. Start-up & Hold-on Voltage
Fig 18. Line Transient Response
(L=10mH, CIN=COUT=10mF, VIN=1.8V)
Rev. 1.00
9
October 04, 2012
HT77xxSA
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 (http://www.holtek.com.tw/english/
literature/package.pdf) for the latest version of the package information.
3-pin SOT23 Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
0.039
―
0.051
A1
―
―
0.004
A2
0.028
―
0.035
b
0.014
―
0.020
C
0.004
―
0.010
D
0.106
―
0.122
E
0.055
―
0.071
e
―
0.075
―
H
0.102
―
0.118
L
0.015
―
―
θ
0°
―
9°
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
1.00
―
1.30
A1
―
―
0.10
A2
0.70
―
0.90
b
0.35
―
0.50
C
0.10
―
0.25
D
2.70
―
3.10
E
1.40
―
1.80
e
―
1.90
―
H
2.60
―
3.00
L
0.37
―
―
θ
0°
―
9°
10
October 04, 2012
HT77xxSA
5-pin SOT23-5 Outline Dimensions
Symbol
A
Dimensions in inch
Min.
Nom.
Max.
0.039
―
0.051
A1
―
―
0.004
A2
0.028
―
0.035
b
0.014
―
0.020
C
0.004
―
0.010
D
0.106
―
0.122
E
0.055
―
0.071
e
―
0.075
―
H
0.102
―
0.118
L
0.015
―
―
θ
0°
―
9°
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
1.00
―
1.30
A1
―
―
0.10
A2
0.70
―
0.90
b
0.35
―
0.50
C
0.10
―
0.25
D
2.70
―
3.10
E
1.40
―
1.80
e
―
1.90
―
H
2.60
―
3.00
L
0.37
―
―
θ
0°
―
9°
11
October 04, 2012
HT77xxSA
3-pin SOT89 Outline Dimensions
Symbol
Dimensions in inch
Min.
Nom.
Max.
A
0.173
―
0.181
B
0.059
―
0.072
C
0.090
―
0.102
D
0.035
―
0.047
E
0.155
―
0.167
F
0.014
―
0.019
G
0.017
―
0.022
H
―
0.059
―
I
55
―
63
J
14
―
17
Symbol
Rev. 1.00
Dimensions in mm
Min.
Nom.
Max.
A
4.39
―
4.60
B
1.50
―
1.83
C
2.29
―
2.59
D
0.89
―
1.19
E
3.94
―
4.24
F
0.36
―
0.48
G
0.43
―
0.56
H
―
1.50
―
I
1.40
―
1.60
J
0.36
―
0.43
12
October 04, 2012
HT77xxSA
3-pin TO92 Outline Dimensions
Symbol
Min.
Nom.
Max.
A
0.170
―
0.200
B
0.170
―
0.200
C
0.500
―
―
D
0.011
―
0.020
E
0.090
―
0.110
F
0.045
―
0.055
G
0.045
―
0.065
H
0.130
―
0.160
α
0°
―
10°
Symbol
A
Rev. 1.00
Dimensions in inch
Dimensions in mm
Min.
Nom.
Max.
4.32
―
5.08
B
4.32
―
5.08
C
12.70
―
―
D
0.28
―
0.51
E
2.29
―
2.79
F
1.14
―
1.40
G
1.14
―
1.65
H
3.30
―
4.06
α
0°
―
10°
13
October 04, 2012
HT77xxSA
Product Tape and Reel Specifications
Reel Dimensions
SOT23-3, SOT23-5
Symbol
Description
Dimensions in mm
A
Reel Outer Diameter
178.0±1.0
B
Reel Inner Diameter
62.0±1.0
C
Spindle Hole Diameter
13.0±0.2
D
Key Slit Width
2.50±0.25
T1
Space Between Flange
8.4 +1.5/-0.0
T2
Reel Thickness
11.4 +1.5/-0.0
SOT89-3
Symbol
Description
Dimensions in mm
A
Reel Outer Diameter
178.0±1.0
B
Reel Inner Diameter
62.0±1.0
C
Spindle Hole Diameter
13.0±0.2
D
Key Slit Width
2.50±0.25
T1
Space Between Flange
8.4 +1.5/-0.0
T2
Reel Thickness
11.4 +1.5/-0.0
Rev. 1.00
14
October 04, 2012
HT77xxSA
TO92 Reel Dimensions (Unit: mm)
Rev. 1.00
15
October 04, 2012
HT77xxSA
Carrier Tape Dimensions
 SOT23-3, SOT23-5
Symbol
Description
Dimensions in mm
W
Carrier Tape Width
8.0±0.3
P
Cavity Pitch
4.0±0.1
E
Perforation Position
1.75±0.10
F
Cavity to Perforation (Width Direction)
3.50±0.05
D
Perforation Diameter
1.5 +0.1/-0.00
D1
Cavity Hole Diameter
1.5 +0.1/-0.00
P0
Perforation Pitch
P1
Cavity to Perforation (Length Direction)
2.00±0.05
4.0±0.1
A0
Cavity Length
3.15±0.10
B0
Cavity Width
3.2±0.1
K0
Cavity Depth
1.4±0.1
t
Carrier Tape Thickness
C
Cover Tape Width
Rev. 1.00
0.20±0.03
5.3±0.1
16
October 04, 2012
HT77xxSA
SOT89-3
Symbol
Description
W
Carrier Tape Width
Dimensions in mm
12.0+0.3/-0.1
P
Cavity Pitch
E
Perforation Position
1.75±0.10
8.0±0.1
F
Cavity to Perforation (Width Direction)
5.50±0.05
D
Perforation Diameter
1.5 +0.1/-0.00
D1
Cavity Hole Diameter
1.5 +0.1/-0.00
P0
Perforation Pitch
4.0±0.1
P1
Cavity to Perforation (Length Direction)
2.0±0.1
A0
Cavity Length
4.8±0.1
B0
Cavity Width
4.5±0.1
K0
Cavity Depth
t
Carrier Tape Thickness
C
Cover Tape Width
Rev. 1.00
1.8±0.1
0.300±0.013
9.3±0.1
17
October 04, 2012
HT77xxSA
Carrier Tape Dimensions
TO92
Symbol
Description
Dimensions in mm
I1
Taped Lead Length
P
Component Pitch
12.7±1.0
(2.5)
P0
Perforation Pitch
12.7±0.3
P2
Component to Perforation (Length Direction)
6.35±0.40
F1
Lead Spread
2.5 +0.4/-0.0
F2
Lead Spread
2.5 +0.4/-0.0
Δh
Component Alignment
W
Carrier Tape Width
W0
Hold-down Tape Width
6.0±0.5
W1
Perforation Position
9.0±0.5
W2
Hold-down Tape Position
H0
Lead Clinch Height
16.0±0.5
H1
Component Height
Less than 24.7
D0
Perforation Diameter
0.0±0.1
18.0 +1.0/-0.5
(0.5)
4.0±0.2
t
Taped Lead Thickness
0.7±0.2
H
Component Base Height
19.0±0.5
Note: Thickness less than 0.38±0.05mm~0.5mm.
P0 Accumulated pitch tolerance: ±1mm/20pitches.
( ) Bracketed figures are for reference only.
Rev. 1.00
18
October 04, 2012
HT77xxSA
Holtek Semiconductor Inc. (Headquarters)
No.3, Creation Rd. II, Science Park, Hsinchu, Taiwan
Tel: 886-3-563-1999
Fax: 886-3-563-1189
http://www.holtek.com.tw
Holtek Semiconductor Inc. (Taipei Sales Office)
4F-2, No. 3-2, YuanQu St., Nankang Software Park, Taipei 115, Taiwan
Tel: 886-2-2655-7070
Fax: 886-2-2655-7373
Fax: 886-2-2655-7383 (International sales hotline)
Holtek Semiconductor (China) Inc.
Building No. 10, Xinzhu Court, (No. 1 Headquarters), 4 Cuizhu Road, Songshan Lake, Dongguan, China 523808
Tel: 86-769-2626-1300
Fax: 86-769-2626-1311
Holtek Semiconductor (USA), Inc. (North America Sales Office)
46729 Fremont Blvd., Fremont, CA 94538, USA
Tel: 1-510-252-9880
Fax: 1-510-252-9885
http://www.holtek.com
Copyright© 2012 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
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October 04, 2012