AIC AIC1899PK 1.0mhz current-mode step-up dc/dc converter Datasheet

AIC1899
1.0MHz Current-Mode Step-Up DC/DC Converter
FEATURES
DESCRIPTION
Fixed Frequency 1.0MHz Current-Mode PWM
The current-mode pulse-width modulation, AIC1899,
Operation.
step up converter is designed for MP3 player. The
Adjustable Output Voltage up to 24V.
built-in high voltage N-channel MOSFET allows
2.5V to 5.5V Input Range.
AIC1899 for step-up applications with up to 24V
Maximum 0.1µA Shutdown Current.
output voltage, and other low-side switching DC/DC
Programmable Soft-Start.
converter.
Tiny Inductor and Capacitors are allowed.
Space-Saving TSOT-23-6 and SOT-23-6
The high switching frequency allows the use of
Package.
small external components. The Soft-Start function
is programmable with an external capacitor, which
APPLICATIONS
sets the input current ramp rate.
OLED Driver for MP3 Player
White LED Backlight
The AIC1899 is available in a space-saving
TSOT-23-6 and SOT-23-6 package.
TYPICAL APPLICATION CIRCUIT
L1
Vin=3V
U1 AIC1899
IN
Cin
33uF/6.3V
+
22uH
SHDN FB
Fig. 1
15V/15mA
SS0540
R1
11k
SS GND
R2
1k
C2
33nF
Analog Integrations Corporation
D1
LX
Cout
10uF/25V
+
Co
0.1uF
CF 1nF
Typical Step up Application Circuit
Si-Soft Research Center
3A1, No.1, Li-Hsin Rd. I, Science Park, Hsinchu 300, Taiwan, R.O.C.
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
DS-1899G-01
121208
1
AIC1899
ORDERING INFORMATION
AIC1899XXXX
PIN CONFIGURATION
PACKING TYPE
TR: TAPE & REEL
BG: BAG
PACKAGE TYPE
G: SOT-23-6
K: TSOT-23-6
P: LEAD FREE COMMERCIAL
G: GREEN PACKAGE
Example: AIC1899PGTR
in Lead Free SOT-23-6 Package & Tape
SOT-23-6 / TSOT-23-6
FRONT VIEW
6
5
1: LX
2: GND
1899G
3: FB
4: SHDN
5: SS
2
1
6: IN
4
3
Note: Pin1 is determined by orienting
the package marking as shown.
& Reel Packing Type
AIC1899PKTR
in Lead Free TSOT-23-6 Package & Tape
& Reel Packing Type
TSOT-23-6 Marking
Part No.
Marking
Part No.
Marking
AIC1899PK
899PK
AIC1899GK
899GK
Part No.
Marking
Part No.
Marking
AIC1899PG
1899P
AIC1899GG
1899G
SOT-23-6 Marking
ABSOLUTE MAXIMUM RATINGS
IN, SHDN , FB, SS to GND
LX to GND
LX Pin RMS Current
Operating Temperature Range
Junction Temperature
Storage Temperature Range
Lead Temperature (soldering, 10s)
-0.3V to +6V
-0.3V to +27V
0.14A
-40°C to 85°C
125°C
-65°C to 150°C
260°C
Thermal Resistance Junction to Case
130°C /W
Thermal Resistance Junction to Ambient
220°C /W
(Assume no ambient airflow, no heatsink)
Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.
2
AIC1899
ELECTRICAL CHARACTERISTICS
(VIN=V SHDN =3V, FB=GND, SS=Open, TA=25°°C, unless otherwise specified) (Note 1)
PARAMETER
Input Supply Range
SYMBOL
CONDITIONS
VIN
VOUT
VIN Undervoltage Lockout
UVLO VIN rising, 50mV hysteresis
IIN
Output Current
Iout
Shutdown Supply Current
TYP
2.5
Output Voltage Adjust Range
Quiescent Current
MIN
MAX UNITS
5.5
V
24
V
2.2
VFB = 1.3V, not switching
V
0.1
0.2
VFB = 1.0V, switching
1
5
Vin = 3V, Vout = 15V
15
Vin = 3.3V, Vout = 15V
17
mA
mA
V SHDN = 0, TA = +25°C
0.01
0.5
µA
V SHDN = 0
0.01
10
µA
1.23
1.255
V
21
80
nA
0.05
0.20
%/V
1700
KHz
ERROR AMPLIFIER
Feedback Regulation Set Point
VFB
FB Input Bias Current
IFB
Line Regulation
1.205
VFB = 1.24V
2.6V < VIN < 5.5V
OSCILLATOR
Frequency
fOSC
800
1000
Maximum Duty Cycle
DC
80
82
%
POWER SWITCH
On-Resistance
RDS(ON) Vin = 5V
Leakage Current
ILX(OFF)
VLX = 24V, TA = +25°C
1.2
1.6
0.1
1
Ω
µA
VLX = 24V
10
Reset Switch Resistance
Guaranteed By Design
100
Ω
Charge Current
VSS = 1.2V
7.0
µA
0.3
V
SOFT-START
1.5
4
CONTROL INPUT
Input Low Voltage
VIL
V SHDN , VIN = 2.5V to 5.5V
Input High Voltage
VIH
V SHDN , VIN = 2.5V to 5.5V
SHDN Input Current
I SHDN
V SHDN = 1.8V
V SHDN = 0
1.0
V
25
50
0.01
0.1
µA
Note 1: Specifications are production tested at TA=25°C. Specifications over the -40°C to 85°C operating
temperature range are assured by design, characterization and correlation with Statistical Quality
Controls (SQC).
3
AIC1899
TYPICAL PERFORMANCE CHARACTERISTICS
1.25
1.05
Feedback Voltage (V)
Switching Frequency (MHz)
1.15
VIN=3.6V
1.00
0.95
0.90
0.85
-40
-20
0
20
40
60
80
1.24
VIN=3.6V
1.23
1.22
1.21
1.20
-50
0.80
100
-25
0
VIN=4.2V
90
VIN=3.6V
VIN=3.3V
VIN=2.7V
VIN=2.5V
80
75
100
Feedback Pin Voltage
VIN=5.0V
VIN=4.2V
85
75
70
VOUT=5.0V
L1: 10uH, GTSK-51-100M
65
50
90
Efficiency (%)
Efficiency (%)
Fig. 3
Switching Frequency vs. Temperature
85
25
Temperature (°C)
Temperature (°C)
Fig. 2
80
VIN=3.6V
VIN=3.3V
75
70
VOUT=15V
L1: 22uH, SLF6025-220MR
65
60
60
0
15
Fig. 4
30
45
60
75
90
0
15
Output Current (mA)
Efficiency vs. Output Current
Fig. 5
30
45
60
Output Current (mA)
Efficiency vs. output current
15.5
5.50
VIN=3.3V
VIN=3.6V
5.25
Output Voltage (V)
Output Voltage (V)
5.00
4.75
15.0
14.5
14.0
13.5
4.50
1
10
Output Current (mA)
Fig. 6
100
μH)
Load Regulation (L1=10
1
10
100
Output Current (mA)
Fig. 7
Load Regulation (L1=22
μH)
4
AIC1899
TYPICAL PERFORMANCE CHARACTERISTICS (Continued)
1.9
1.10
TA=25oC
1.8
1.7
1.6
RDSON (Ω)
FREQUENCY(MHz)
1.05
1.00
0.95
1.5
1.4
1.3
1.2
1.1
1.0
0.90
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
SUPPLY VOLTAGE(V)
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Fig. 8 Frequency vs. Supply Voltage
Fig. 9 RDS-ON vs. Supply Voltage
1.4
85
SUPPLY CURRENT (µA)
SUPPLY CURRENT (mA)
FB=1.0V
1.2
SHDN=1.0V
1.0
0.8
80
FB=1.3V
75
SHDN=1.0V
70
0.6
2.5
3.0
3.5
4.0
4.5
5.0
5.5
65
2.5
3.0
SUPPLY VOLTAGE (V)
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
Fig. 10 Switching Current
VOUT
3.5
Fig. 11
Non-Switching Current
VSHDN
VLX
VOUT
VLX
IL
Fig. 12 Operation Waveform
(VIN=3V; VOUT=15V, IOUT=15mA, Test circuit as Fig.1)
Fig. 13 Start-up Waveform
(VIN=3V; VOUT=15V, IOUT=15mA, Test circuit as Fig.1)
5
AIC1899
BLOCK DIAGRAM
VIN
Control
PWM/PFM
I9
R3
Soft Start
R4
Error Amp
-
+
-
+
Q1
Q2
FB
1
8
R1
Control
Logic
SHDN
Driver
RC
CC
1.0MHz
Oscillator
R2
LX
x1
Slope Compensation
Current AMP x 5
+
x20
RS
-
SS
4µA
PWM
Comparator
GND
PIN DESCRIPTIONS
PIN 1: LX
-
Power Switching Connection.
Connect LX to inductor and
output
rectifier.
Keep
the
distance
between
the
components as close to LX as
possible.
PIN 2: GND -
Ground.
PIN 3: FB
Feedback Input. Connect a
resistive voltage-divider from the
output to FB to set the output
voltage.
-
PIN 4: SHDN - Shutdown Input. Drive SHDN
low to turn off the converter. To
automatically start the converter,
connect SHDN to IN. Drive
SHDN with a slew rate of
0.1V/µs or greater. Do not leave
SHDN unconnected. SHDN
draws up to 50µA.
PIN 5: SS
-
Soft-Start Input. Connect a
soft-start capacitor from SS to
GND in order to soft-start the
converter. Leave SS open to
disable the soft-start function.
PIN 6: IN
-
Internal Bias Voltage Input.
Connect IN to the input voltage
source. Bypass IN to GND with
a capacitor sitting as close to IN
as possible.
6
AIC1899
APPLICATION INFORMATION
The AIC1899 operates well with a variety of
K=
external components. The components in Figure 1
∆iL
: Ratio of the inductor peak-to-peak
IL
are suitable for most applications. See the
following
sections
to
optimize
AC current to average DC
external
components for a particular application.
inductor current
The inductance value is then given by:
2
Inductor Selection
L=
A 22µH inductor is recommended for most
AIC1899 applications. Although small size and
Vi (min) ⋅ η ⋅ D
K ⋅ f ⋅ Vo ⋅ I o (max)
where:
high efficiency are major concerns, the inductor
D = Duty cycle =
should have low core losses at 1.0MHz and low
DCR (copper wire resistance).
Vi (min) − (V f + Vo )
I i (max) ⋅ R ds (on ) − (V f + Vo )
V f : Catch diode forward drop
f : Switching frequency
Inductor selection depends on input voltage,
output voltage, maximum current, size, and
availability of inductor values. Other factors can
include efficiency and ripple voltage. Inductors are
specified by their inductance (L), peak current
(IL(PK)), and resistance (DCR). The following
step-up circuit equations are useful in choosing
the inductor values based on the application. They
allow the trading of peak current and inductor
value while considering component availability
and cost.
The equation used here assumes a constant K,
which is the ratio of the inductor peak-to-peak AC
current to average DC inductor current. A good
compromise between the size of the inductor
versus loss and output ripple is to choose a K of
0.3 to 0.5. The peak inductor current is then given
by:
Capacitor Selection
The AIC1899 operates with both tantalum and
ceramic output capacitors. When using tantalum
capacitors, the zero caused by the ESR of the
tantalum is used to ensure stability. When using
ceramic capacitors, the zero due to the ESR will
be at too high a frequency to be useful in
stabilizing the control loop. When using ceramic
capacitors,
increase
add
the
a
feedforward
phase
margin,
capacitor
improving
to
the
control-loop stability.
Diode Selection
Schottky diodes, with their low forward voltage
drop and fast reverse recovery, are the ideal
i L ( pk )
I o (max) ⋅ Vo  K 
=
⋅ 1 + 
η ⋅ Vi (min) 
2
where:
IO(max): Maximum output current, (A)
Vi(min): Minimum input voltage, (V)
η
: Conversion efficiency, 0.8
choices for AIC1899 applications. The forward
voltage drop of an Schottky diode represents the
conduction losses in the diode, while the diode
capacitance (CT or CD) represents the switching
losses. For diode selection, both forward voltage
drop
and
diode
capacitance
need
to
be
considered. Schottky diodes with higher current
ratings usually have lower forward voltage drop
7
AIC1899
and larger diode capacitance, which can cause
significant
switching
losses
at
the
Calculate
1.0MHz
R1 and R2 using the equation:

R 1  Vo
= 
− 1
R 2  VFB

switching frequency of AIC1899.
VFB , the step-up regulator feedback set
Setting the Output Voltage
where
The AIC1899 operates with an adjustable output
point, is 1.23V. Connect the resistive-divider as
close to the IC as possible.
from Vin to 24V. Connect a resistive voltage
divider from the output to FB (see Fig.1).
APPLICATION EXAMPLES
L1
Vin=3V~4.2V
U1 AIC1899
IN
Cin
33uF
+
D1
15V/15mA
SS0540
LX
SHDN FB
R1
11k
SS GND
C2
33nF
Fig. 14
22uH
R2
1k
Cout
10uF
+
Co
0.1uF
CF 1nF
1-Cell Li-Ion boost converter for OLED Application
8
AIC1899
PHYSICAL DIMENSIONS (unit: mm)
TSOT-23-6
S
Y
M
B
O
L
A
A
E
E1
D
e
e1
SEE VIEW B
WITH PLATING
c
A
A2
b
BASE METAL
SECTION A-A
0.25
A1
GAUGE PLANE
SEATING PLANE
L
θ
L1
VIEW B
TSOT-23-6
MILLIMETERS
MIN.
MAX.
A
-
1.00
A1
0
0.10
A2
0.70
0.90
b
0.30
0.50
c
0.08
0.22
D
2.80
3.00
E
2.60
3.00
E1
1.50
1.70
e
0.95 BSC
e1
1.90 BSC
L
0.60
0.30
L1
θ
0.60 REF
0°
8°
Note : 1. Refer to JEDEC MO-193AA.
2. Dimension "D" does not include mold flash, protrusions
or gate burrs. Mold flash, protrusion or gate burrs shall not
exceed 6 mil per side.
3. Dimension "E1" does not include inter-lead flash or protrusions.
4. Controlling dimension is millimeter, converted inch
dimensions are not necessarily exact.
9
AIC1899
SOT-23-6
D
1
E
A
A
e1
S
Y
M
B
O
L
E
e
SEE VIEW B
b
WITH PLATING
2
A
c
A
BASE METAL
1
A
SECTION A-A
5
.2
0
L
L1
VIEW B
GAUGE PLANE
SEATING PLANE
θ
SOT-23-6
MILLIMETERS
MIN.
MAX.
A
0.95
1.45
A1
0.05
0.15
A2
0.90
1.30
b
0.30
0.50
c
0.08
0.22
D
2.80
3.00
E
2.60
3.00
E1
1.50
1.70
e
0.95 BSC
e1
1.90 BSC
L
0.30
0.42 REF
L1
θ
0.60
0°
8°
Note : 1. Refer to JEDEC MO-178AB.
2. Dimension "D" does not include mold flash, protrusions
or gate burrs. Mold flash, protrusion or gate burrs shall not
exceed 10 mil per side.
3. Dimension "E1" does not include inter-lead flash or protrusions.
4. Controlling dimension is millimeter, converted inch
dimensions are not necessarily exact.
Note:
Information provided by AIC is believed to be accurate and reliable. However, we cannot assume responsibility for use of any
circuitry other than circuitry entirely embodied in an AIC product; nor for any infringement of patents or other rights of third
parties that may result from its use. We reserve the right to change the circuitry and specifications without notice.
Life Support Policy: AIC does not authorize any AIC product for use in life support devices and/or systems. Life support devices
or systems are devices or systems which, (I) are intended for surgical implant into the body or (ii) support or sustain life, and
whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably
expected to result in a significant injury to the user.
10
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