Analogic AAT1230IRN 18v 100ma step-up converter Datasheet

AAT1230/1230-1
18V 100mA Step-Up Converter
General Description
Features
The AAT1230/1230-1 is a high frequency, high efficiency boost converter capable of 18V maximum
output voltage. The internal power switch can deliver 100mA load current. It is the ideal power solution
to power OLED, LCD, and CCD applications operating from a single cell lithium-ion battery.
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Hysteretic control provides up to 2MHz switching
frequency and fast response to load transients with
small, low-cost external components. The fully integrated control IC simplifies the design while reducing the total PCB footprint. The AAT1230/1230-1
offers a true load disconnect feature which isolates
the load from the power source when EN/SET is
pulled low. This eliminates leakage current and
maintains zero voltage at the output while disabled.
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The output voltage can be dynamically set by activating one of two reference levels (FB1 or FB2)
through the SEL logic pin. Optionally, AnalogicTech’s
Simple Serial Control™ (S2Cwire™) single wire
interface provides dynamic programmability across
a wide output voltage range through the EN/SET pin.
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The AAT1230/1230-1 are available in a Pb-free,
thermally-enhanced 16-pin 3x4mm TDFN low-profile package or a Pb-free 12-pin TSOPJW package.
VIN Range: 2.7V to 5.5V
Maximum Output: 18V @ 100mA
True Load Disconnect
Dynamic Voltage Control Options
Hysteretic Control
— No External Compensation Components
— Excellent Load Transient Response
— High Efficiency at Light Load
Up to 2MHz Switching Frequency
Ultra-Small Inductor and Capacitors
Integrated Low RDS(ON) MOSFET Switches
Up to 85% Efficiency
<1µA Shutdown Current
Integrated Soft Start
Two Turn-On Time Options
— AAT1230: TSS = 0.35ms
— AAT1230-1: TSS = 3.5ms
Cycle-by-Cycle Current Limit
Short-Circuit, Over-Temperature Protection
Available in TSOPJW-12 or TDFN34-16
Package
-40°C to +85°C Temperature Range
Applications
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Typical Application
CCD Bias Circuit
Digital Still Cameras
LCD Bias Circuit
Mobile Handsets
MP3 Players
OLED Displays
PDAs and Notebook PCs
L1
2.2μH
C1
2.2μF
VBAT
3.6V
VP
VIN
D1
Schottky
18V @ 100mA
LIN
AAT1230/
AAT1230-1
SW
PGND
Enable/Set
SwitchReg™
R1
78.7kΩ
C2
2.2μF, 25V
FB1
R2
562Ω
EN/SET
FB2
Select
1230.2007.06.1.6
SEL
GND
R3
4.99kΩ
1
AAT1230/1230-1
18V 100mA Step-Up Converter
Pin Descriptions
Pin #
TSOPJW-12
TDFN34-16
Symbol
1
15, 16
VP
2
14
EN/SET
3
13
SEL
4
5
6, 7
12
11
9, 10
VIN
N/C
SW
8
6, 7, 8
PGND
9
10
5
4
GND
FB2
11
3
FB1
12
N/A
1, 2
EP
LIN
Function
Input power pin; connected to the source of the P-channel MOSFET.
Connect to the input capacitor(s).
IC active high enable pin. Alternately, input pin for S2Cwire control utilizing FB2 reference.
Logic high selects FB1 high output reference; logic low selects FB2 low
output reference. Pull low for S2Cwire control.
Input voltage for the converter. Connect this pin directly to the VP pin.
No connection.
Boost converter switching node. Connect the power inductor between
this pin and LIN pin.
Power ground for the boost converter; connected to the source of the
N-channel MOSFET. Connect to the input and output capacitor return.
Ground pin.
Feedback pin for low output voltage set point. Pin set to 0.6V when
SEL is low and disabled when SEL is high. Voltage is set from 0.6V to
1.2V with S2Cwire control.
Feedback pin for high output voltage set point. Pin set to 1.2V when
SEL is high and disabled when SEL is low. Disabled with S2Cwire
control.
Switched power input. Connected to the power inductor.
Exposed paddle (bottom). Tied to SW pins. May be connected to SW
pins or left floating.
Pin Configuration
TSOPJW-12
(Top View)
VP
EN/SET
SEL
VIN
N/C
SW
2
1
12
2
11
3
10
4
9
5
8
6
7
TDFN34-16
(Top View)
LIN
FB1
FB2
GND
PGND
SW
LIN
LIN
FB1
FB2
GND
PGND
PGND
PGND
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
VP
VP
EN/SET
SEL
VIN
N/C
SW
SW
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
AAT1230/1230-1 Feature Options
Part Number
Soft Start Time, TSS
Package
AAT1230ITP
AAT1230IRN
AAT1230ITP-1
0.35ms
0.35ms
3.5ms
TSOPJW-12
TDFN34-16
TSOPJW-12
Absolute Maximum Ratings1
TA = 25°C, unless otherwise noted.
Symbol
VIN
SW
LIN, EN/SET,
SEL, FB1, FB2
TJ
TS
TLEAD
Value
Units
Input Voltage
Switching Node
Description
-0.3 to 6.0
20
V
V
Maximum Rating
VIN + 0.3
V
-40 to 150
-65 to 150
300
°C
°C
°C
Value
Units
Operating Temperature Range
Storage Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Recommended Operating Conditions
Symbol
Description
θJA
Thermal Resistance
PD
Maximum Power Dissipation (TA = 25ºC)
TDFN34-16
TSOPJW-12
TDFN34-16
TSOPJW-12
44
160
2270
625
°C/W
mW
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
1230.2007.06.1.6
3
AAT1230/1230-1
18V 100mA Step-Up Converter
Electrical Characteristics1
TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C, VIN = 3.6V.
Symbol
Description
Conditions
Min
Power Supply
VIN
Input Voltage Range
VOUT(MAX)
Maximum Output Voltage
VUVLO
IQ
Load Regulation
Line Regulation
VIN = 2.7V to 5.5V
Quiescent Current
ISHDN
IOUT
VIN Pin Shutdown Current
Output Current
FB1
FB1 Reference Voltage
FB2
FB2 Reference Voltage
ΔVLOADREG
ΔVLINEREG/
ΔVIN
RDS(ON)L
RDS(ON)IN
TSS
TSD
THYS
ILIM
SEL, EN/SET
VSEL(L)
VSEL(H)
VEN/SET(L)
VEN/SET(H)
TEN/SET LO
TEN/SET HI MIN
TEN/SET HI MAX
TOFF
TLAT
IEN/SET
2.7
VIN Rising
Hysteresis
VIN Falling
SEL = GND, VOUT = 14V,
IOUT = 0, Switching2
SEL = GND, FB2 = 1.5V,
Not Switching
EN/SET = GND
2.7V < VIN < 5.5V, VOUT = 18V
IOUT = 0 to 100mA, VIN = 2.7V
to 5.0V, SEL = High
IOUT = 0 to 100mA, VIN = 2.7V
to 5.0V, SEL = Low
IOUT = 0 to 100mA
UVLO Threshold
Over-Temperature Shutdown
Threshold
Shutdown Hysteresis
N-Channel Current Limit
SEL Threshold Low
SEL Threshold High
Enable Threshold Low
Enable Threshold High
EN/SET Low Time
Minimum EN/SET High Time
Maximum EN/SET High Time
EN/SET Off Timeout
EN/SET Latch Timeout
EN/SET Input Leakage
From Enable to Output
Regulation;VOUT = 15V
=
=
=
=
2.7V
5.5V
2.7V
5.5V
Units
5.5
18
2.7
V
V
V
mV
V
150
2.0
40
mA
70
µA
1.0
100
µA
mA
1.164
1.2
1.236
V
0.582
0.6
0.618
V
AAT1230
AAT1230-1
VIN = 3.6V
VIN
VIN
VIN
VIN
Max
1.8
Low Side Switch On Resistance
Input Disconnect Switch
On Resistance
Soft-Start Time
Typ
0.01
%/mA
0.6
%/V
0.06
Ω
0.18
Ω
0.35
3.5
ms
ms
140
°C
15
3.0
°C
A
0.4
1.4
0.4
1.4
0.3
75
50
-1
75
500
500
1
V
V
V
V
µs
ns
µs
µs
µs
µA
1. The AAT1230/1230-1 is guaranteed to meet performance specifications from 0°C to 70°C. Specification over the -40°C to +85°C
operating temperature range is assured by design, characterization, and correlation with statistical process controls.
2. Total input current with prescribed FB resistor network can be reduced with larger resistor values.
4
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
Typical Characteristics
Efficiency vs. Load
DC Regulation
(VOUT = 18V)
(VOUT = 18V)
90
1.0
70
60
VIN = 3.6V
VIN = 4.2V
50
VIN = 5V
0.8
VIN = 5V
Output Error (%)
Efficiency (%)
80
40
30
0.6
0.4
0.2
VIN = 4.2V
0.0
-0.2
VIN = 3.6V
VIN = 2.7V
-0.4
-0.6
-0.8
20
-1.0
0.1
1
10
100
0.1
Output Current (mA)
Efficiency vs. Load
DC Regulation
(VOUT = 15V)
(VOUT = 15V)
100
1.0
0.8
Output Error (%)
VIN = 5V
80
Efficiency (%)
10
Output Current (mA)
90
70
60
VIN = 3.6V
VIN = 4.2V
50
40
30
VIN = 5V
0.6
0.4
0.2
VIN = 4.2V
0.0
-0.2
VIN = 3.6V
VIN = 2.7V
-0.4
-0.6
-0.8
-1.0
20
0.1
1
10
100
0.1
Output Current (mA)
DC Regulation
(VOUT = 12V)
(VOUT = 12V)
1.0
VIN = 3.6V
VIN = 4.2V
60
50
40
30
0.6
0.4
0.2
0.0
VIN = 4.2V
-0.2
VIN = 3.6V
-0.4
VIN = 2.7V
-0.6
-0.8
-1.0
1
10
Output Current (mA)
1230.2007.06.1.6
100
VIN = 5V
0.8
VIN = 5V
70
20
0.1
10
Efficiency vs. Load
Output Error (%)
80
1
Output Current (mA)
90
Efficiency (%)
1
100
0.1
1
10
100
Output Current (mA)
5
AAT1230/1230-1
18V 100mA Step-Up Converter
Typical Characteristics
Line Regulation
Output Voltage Error vs. Temperature
(VOUT = 18V)
(VIN = 5V; VOUT = 18V; IOUT = 100mA)
0.2
2.00
0.1
IOUT = 60mA
1.00
Output Error (%)
Accuracy (%)
1.50
IOUT = 40mA
0.50
0.00
IOUT = 10µA
-0.50
-1.00
0.0
-0.1
-0.2
-0.3
-0.4
-1.50
-0.5
-40
-2.00
2.5
3
3.5
4
4.5
5
5.5
6
-15
85
No Load Input Current vs. Temperature
(VOUT = 18V; EN = High)
(VIN = 3.6V; VOUT = 18V)
1.78
Supply Current (mA)
Supply Current (mA)
60
No Load Input Current vs. Input Voltage
3.0
2.5
2.0
1.5
1.0
0.5
1.76
1.74
1.72
1.70
1.68
1.66
1.64
1.62
0.0
2.5
3
3.5
4
4.5
5
5.5
6
-40
-15
10
35
60
85
Temperature (°°C)
Input Voltage (V)
Output Ripple
Output Ripple
(VIN = 4.2V; VOUT = 18V; IOUT = 100mA)
(VIN = 3.6V; VOUT = 18V; No Load)
18.2
1.0
18.0
4.0
18.0
0.8
17.8
3.0
17.8
0.6
17.6
2.0
17.6
0.4
17.4
1.0
17.4
0.2
17.2
0.0
17.2
0.0
-1.0
17.0
Time (500ns/div)
Output Voltage
(top) (V)
5.0
17.0
Inductor Current
(bottom) (A)
18.2
Inductor Current
(bottom) (A)
Output Voltage
(top) (V)
35
Temperature (°°C)
Input Voltage (V)
6
10
-0.2
Time (50µs/div)
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AAT1230/1230-1
18V 100mA Step-Up Converter
Load Transient Response
Load Transient Response
(VIN = 4.2V; IOUT = 20mA–60mA; VOUT = 18V)
(VIN = 3.6V; IOUT = 20mA–60mA; VOUT = 12V)
18.05
1.2
18.00
0.9
17.95
0.6
17.90
0.3
17.85
0.0
17.80
-0.3
Output Voltage (V) (top)
1.5
12.10
1.50
12.05
1.20
12.00
0.90
11.95
0.60
11.90
0.30
11.85
0.00
11.80
-0.30
Time (200µs/div)
Time (200µs/div)
P-Channel RDS(ON) vs. Input Voltage
N-Channel RDS(ON) vs. Input Voltage
110
300
280
120°C
100
100°C
240
RDS(ON) (mΩ
Ω)
RDS(ON) (mΩ
Ω)
260
220
200
180
160
25°C
140
85°C
2.5
3
3.5
4
4.5
5
5.5
70
60
40
2.5
6
100°C
80
Input Voltage (V)
85°C
25°C
3
3.5
4
4.5
5
5.5
AAT1230-1 Soft Start
(VIN = 3.6V; CIN = 2.2µF; IOUT = 100mA; VOUT = 18V)
2.8
12
2.4
8
2.0
4
1.6
0
1.2
-4
0.8
-8
0.4
-12
0.0
-16
-0.4
1230.2007.06.1.6
20
2.8
15
2.4
10
2.0
5
1.6
0
1.2
-5
0.8
-10
0.4
-15
0.0
Input Current
(bottom) (A)
16
Enable Voltage (middle) (V)
Output Voltage (top) (V)
AAT1230 Soft Start
(VIN = 3.6V; CIN = 2.2µF; IOUT = 100mA; VOUT = 12V)
Time (200µs/div)
6
Input Voltage (V)
Input Current
(bottom) (A)
Enable Voltage (middle) (V)
Output Voltage (top) (V)
120°C
90
50
120
100
Inductor Current (A) (bottom)
18.10
Inductor Current (A) (bottom)
Output Voltage (V) (top)
Typical Characteristics
-0.2
-20
Time (1ms/div)
7
AAT1230/1230-1
18V 100mA Step-Up Converter
Functional Block Diagram
VIN
LIN
VP
Soft-Start
Timer
EN/SET
SW
Control
FB1
VREF1
Output
Select
VREF2
FB2
SEL
GND
Functional Description
The AAT1230/1230-1 consists of a DC/DC boost
controller, an integrated slew rate controlled input
disconnect MOSFET switch, and a MOSFET power
switch. A high voltage rectifier, power inductor, output capacitor, and resistor divider network are
required to implement a DC/DC boost converter.
Control Loop
The AAT1230/1230-1 provides the benefits of current mode control with a simple hysteretic feedback
loop. The device maintains exceptional DC regulation, transient response, and cycle-by-cycle current
limit without additional compensation components.
The AAT1230/1230-1 modulates the power MOSFET switching current in response to changes in
output voltage. This allows the voltage loop to
directly program the required inductor current in
response to changes in the output load.
8
PGND
The switching cycle initiates when the N-channel
MOSFET is turned ON and current ramps up in the
inductor. The ON interval is terminated when the
inductor current reaches the programmed peak
current level. During the OFF interval, the input
current decays until the lower threshold, or zero
inductor current, is reached. The lower current is
equal to the peak current minus a preset hysteresis threshold - which determines the inductor ripple
current. The peak current is adjusted by the controller until the output current requirement is met.
The magnitude of the feedback error signal determines the average input current. Therefore, the
AAT1230/1230-1 controller implements a programmed current source connected to the output
capacitor and load resistor. There is no right-half
plane zero, and loop stability is achieved with no
additional compensation components.
Increased load current results in a drop in the output feedback voltage (FB1 or FB2) sensed through
the feedback resistors (R1, R2, R3). The controller
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
responds by increasing the peak inductor current,
resulting in higher average current in the inductor.
Alternatively, decreased output load results in an
increase in the output feedback voltage (FB1 or
FB2 pin). The controller responds by decreasing
the peak inductor current, resulting in lower average current in the inductor.
At light load, the inductor OFF interval current goes
below zero and the boost converter enters discontinuous mode operation. Further reduction in the
load results in a corresponding reduction in the
switching frequency. The AAT1230/1230-1 provide
pulsed frequency operation which reduces switching
losses and maintains high efficiency at light loads.
Operating frequency varies with changes in the
input voltage, output voltage, and inductor size.
Once the boost converter has reached continuous
mode, further increases in the output load will not
significantly change the operating frequency. A
small 2.2µH (±20%) inductor is selected to maintain
high frequency switching (up to 2MHz) and high
efficiency operation for outputs from 10V to 18V.
Output Voltage Programming
The output voltage may be programmed through a
resistor divider network located from output capacitor to FB1/FB2 pins to ground. Pulling the SEL pin
high activates the FB1 pin which maintains a 1.2V
reference voltage, while the FB2 reference is disabled. Pulling the SEL pin low activates the FB2 pin
which maintains a 0.6V reference, while the FB1
reference is disabled. This function allows dynamic selection between two distinct output voltages
across a 2X range (maximum). An additional resistor between FB1 and FB2 allows the designer to
program the outputs across a reduced <2X range.
Alternatively, the output voltage may be dynamically programmed to any of 16 voltage levels using the
S2Cwire serial digital input. The single wire S2Cwire
interface provides high-speed output voltage programmability across a 2X output voltage range.
S2Cwire functionality is enabled by pulling the SEL
pin low and providing S2Cwire digital clock input to
the EN/SET pin. Table 2 details the FB2 reference
voltage versus S2Cwire rising clock edges.
1230.2007.06.1.6
Soft Start / Enable
The input disconnect switch is activated when a
valid input voltage is present and the EN/SET pin
is pulled high. The slew rate control on the P-channel MOSFET ensures minimal inrush current as
the output voltage is charged to the input voltage,
prior to switching of the N-channel power MOSFET. Monotonic turn-on is guaranteed by the builtin soft-start circuitry. Soft-start eliminates output
voltage overshoot across the full input voltage
range and all loading conditions.
Fast and slow start-up time options are available.
The AAT1230 provides start-up to regulated output
voltage within 0.35ms of a low-to-high transition on
the EN/SET pin. Alternatively, the AAT1230-1 provides start-up to regulated output voltage within
3.5ms of a low-to-high transition on the EN/SET
pin, which dramatically reduces inrush current. A
longer soft-start, or turn-on, time is a preferred feature in battery-powered systems that exhibit higher
source impedances.
Some applications may require the output to be
active when a valid input voltage is present. In
these cases, add a 10kΩ resistor between the VIN,
VP, and EN/SET pins to avoid startup issues.
Current Limit and Over-Temperature
Protection
The switching of the N-channel MOSFET terminates when current limit of 3.0A (typical) is exceeded. This minimizes power dissipation and component stresses under overload and short-circuit conditions. Switching resumes when the current
decays below the current limit.
Thermal protection disables the AAT1230/1230-1
when internal dissipation becomes excessive.
Thermal protection disables both MOSFETs. The
junction over-temperature threshold is 140°C with
-15°C of temperature hysteresis. The output voltage
automatically recovers when the over-temperature
or over-current fault condition is removed.
Under-Voltage Lockout
Internal bias of all circuits is controlled via the VIN
input. Under-voltage lockout (UVLO) guarantees
sufficient VIN bias and proper operation of all internal circuitry prior to soft start.
9
AAT1230/1230-1
18V 100mA Step-Up Converter
R4
10K
JP1
VIN
3
2
1
Enable
JP2
3
2
1
C1
2.2μF
1
2
3
4
5
6
VP
LIN
EN/SET FB1
SEL
FB2
VIN
GND
N/C
PGND
SW
SW
D1
Schottky
L1
2.2μH
U1
12
11
10
9
8
7
VOUT
R1
78.7k
C2
2.2μF
R2
562
R3
4.99k
Select
U1 AAT1230/1230-1 TSOPJW12
C1 10V 0603 2.2μF
C2 25V 0805 2.2μF
D1 30V 0.5A MBR0530T1 SOD-123
L1 2.2μH SD3814-2R2
R1 78.7k 0603
R2 562 0603
R3 4.99k 0603
R4 10k 0603
Figure 1: AAT1230/1230-1 Demo Board Schematic.
Application Information
Selecting the Output Diode
To ensure minimum forward voltage drop and no
recovery, high voltage Schottky diodes are considered the best choice for the AAT1230/1230-1 boost
converter. The AAT1230/1230-1 output diode is
sized to maintain acceptable efficiency and reasonable operating junction temperature under full load
operating conditions. Forward voltage (VF) and
package thermal resistance (θJA) are the dominant
factors to consider in selecting a diode. The diode's
published current rating may not reflect actual operating conditions and should be used only as a comparative measure between similarly rated devices.
20V rated Schottky diodes are recommended for
outputs less than 15V, while 30V rated Schottky
diodes are recommended for outputs greater than
15V.
The switching period is divided between ON and
OFF time intervals.
1
= TON + TOFF
FS
During the ON time, the N-channel power MOSFET is conducting and storing energy in the boost
inductor. During the OFF time, the N-channel
power MOSFET is not conducting. Stored energy is
10
transferred from the input battery and boost inductor to the output load through the output diode.
Duty cycle is defined as the ON time divided by the
total switching interval.
D=
TON
TON + TOFF
= TON ⋅ FS
The maximum duty cycle can be estimated from
the relationship for a continuous mode boost converter. Maximum duty cycle (DMAX) is the duty
cycle at minimum input voltage (VIN(MIN)).
DMAX =
VOUT - VIN(MIN)
VOUT
The average diode current during the OFF time can
be estimated.
IAVG(OFF) =
IOUT
1 - DMAX
The following curves show the VF characteristics
for different Schottky diodes (100°C case). The VF
of the Schottky diode can be estimated from the
average current during the off time.
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
Selecting the Boost Inductor
Forward Current (mA)
10000
B340LA
MBR0530
1000
ZHCS350
100
BAT42W
10
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
Forward Voltage (V)
The average diode current is equal to the output
current.
The AAT1230/1230-1 controller utilizes hysteretic
control and the switching frequency varies with output load and input voltage. The value of the inductor determines the maximum switching frequency
of the AAT1230/1230-1 boost converter. Increased
output inductance decreases the switching frequency, resulting in higher peak currents and
increased output voltage ripple. To maintain 2MHz
maximum switching frequency and stable operation, an output inductor sized from 1.5µH to 2.7µH
is recommended.
A better estimate of DMAX is possible when VF is
known.
IAVG(TOT) = IOUT
PLOSS(DIODE) = IAVG(TOT) · VF
= IOUT · VF
Diode junction temperature can be estimated.
TJ(DIODE) = TAMB + ΘJA · PLOSS(DIODE)
Output diode junction temperature should be
maintained below 110ºC, but may vary depending
on application and/or system guidelines. The
diode θJA can be minimized with additional PCB
area on the cathode. PCB heatsinking the anode
may degrade EMI performance.
The reverse leakage current of the rectifier must be
considered to maintain low quiescent (input) current and high efficiency under light load. The rectifier reverse current increases dramatically at high
temperatures.
(VOUT + VF - VIN(MIN))
(VOUT + VF)
Where VF is the Schottky diode forward voltage. If
not known, it can be estimated at 0.5V.
Manufacturer’s specifications list both the inductor
DC current rating, which is a thermal limitation, and
peak inductor current rating, which is determined
by the saturation characteristics. Measurements at
full load and high ambient temperature should be
completed to ensure that the inductor does not saturate or exhibit excessive temperature rise.
The output inductor (L) is selected to avoid saturation at minimum input voltage, maximum output load
conditions. Peak current may be estimated using
the following equation, assuming continuous conduction mode. Worst-case peak current occurs at
minimum input voltage (maximum duty cycle) and
maximum load. Switching frequency can be estimated from the curves and assumes a 2.2µH inductor.
Switching Frequency (MHz)
The average output current multiplied by the forward diode voltage determines the loss of the output diode.
DMAX =
2.0
VIN = 3.0V
VOUT = 18V
1.8
VIN = 3.0V
VOUT = 15V
1.6
VIN = 3.6V
VOUT = 18V
1.4
VIN = 3.6V
VOUT = 15V
1.2
1.0
0.8
0.6
VIN = 2.7V
VOUT = 18V
0.4
40
50
VIN = 2.7V
VOUT = 15V
60
70
80
90
100
Output Current (mA)
1230.2007.06.1.6
11
AAT1230/1230-1
Switching Frequency (MHz)
18V 100mA Step-Up Converter
2.0
1.8
VIN = 3.0V
VOUT = 12V
1.6
VIN = 3.0V
VOUT = 10V
VIN = 3.6V
VOUT = 12V
VIN = 3.6V
VOUT = 10V
1.4
1.2
1.0
0.8
VIN = 2.7V
VOUT = 10V
0.6
0.4
40
50
VIN = 2.7V
VOUT = 12V
60
70
80
90
100
EMI performance when applied to the SW node
(switching) of the AAT1230/1230-1.
Shielded inductors provide decreased EMI and may
be required in noise sensitive applications.
Unshielded chip inductors provide significant space
savings at a reduced cost compared to shielded
(wound and gapped) inductors. In general, chiptype inductors have increased winding resistance
(DCR) when compared to shielded, wound varieties.
Output Current (mA)
Selecting the Boost Capacitors
At light load and low output voltage, the controller
reduces the operating frequency to maintain maximum operating efficiency. As a result, further
reduction in output load does not reduce the peak
current. Minimum peak current can be estimated
from 0.5A to 0.75A.
The high output ripple inherent in the boost converter necessitates low impedance output filtering.
Multi-layer ceramic (MLC) capacitors provide small
size and adequate capacitance, low parasitic
equivalent series resistance (ESR) and equivalent
series inductance (ESL), and are well suited for
use with the AAT1230/1230-1 boost regulator.
MLC capacitors of type X7R or X5R are recommended to ensure good capacitance stability over
the full operating temperature range.
The RMS current flowing through the boost inductor is equal to the DC plus AC ripple components.
Under worst-case RMS conditions, the current
waveform is critically continuous. The resulting
RMS calculation yields worst-case inductor loss.
The RMS current value should be compared
against the manufacturer's temperature rise, or
thermal derating, guidelines.
The output capacitor is sized to maintain the output
load without significant voltage droop (ΔVOUT) during the power switch ON interval, when the output
diode is not conducting. A ceramic output capacitor from 2.2µF to 4.7µF is recommended. Typically,
25V rated capacitors are required for the 18V boost
output. Ceramic capacitors sized as small as 0805
are available which meet these requirements.
IPEAK =
IOUT
D
· VIN(MIN)
+ MAX
(1 - DMAX)
(2 · FS · L)
IRMS =
IPEAK
3
For a given inductor type, smaller inductor size leads
to an increase in DCR winding resistance and, in
most cases, increased thermal impedance. Winding
resistance degrades boost converter efficiency and
increases the inductor’s operating temperature.
PLOSS(INDUCTOR) = IRMS2 · DCR
To ensure high reliability, the inductor temperature
should not exceed 100ºC. In some cases, PCB
heatsinking applied to the AAT1230/1230-1 LIN
node (non-switching) can improve the inductor's
thermal capability. PCB heatsinking may degrade
12
MLC capacitors exhibit significant capacitance
reduction with applied voltage. Output ripple
measurements should confirm that output voltage
droop is acceptable. Voltage derating can minimize this factor, but results may vary with package
size and among specific manufacturers.
Output capacitor size can be estimated at a switching frequency (FSW) of 500kHz (worst-case).
COUT =
IOUT · DMAX
FS · ΔVOUT
The boost converter input current flows during both
ON and OFF switching intervals. The input ripple
current is less than the output ripple and, as a result,
less input capacitance is required. A ceramic output
capacitor from 1µF to 3.3µF is recommended.
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
Minimum 6.3V rated ceramic capacitors are required
at the input. Ceramic capacitors sized as small as
0603 are available which meet these requirements.
The AAT1230/1230-1 provides excellent load transient response, but large capacitance tantalum or
solid-electrolytic capacitors may be desired. These
can replace (or be used in parallel with) ceramic
capacitors. Both tantalum and OSCON-type capacitors are suitable due to their low ESR and excellent
temperature stability (although they exhibit much
higher ESR than MLC capacitors). Aluminum-electrolytic types are less suitable due to their high ESR
characteristics and temperature drift. Unlike MLC
capacitors, these types are polarized and proper orientation on input and output pins is required. 30% to
70% voltage derating is recommended for tantalum
capacitors.
Setting the Output Voltage
The output voltage may be programmed through a
resistor divider network located from the output to
FB1 and FB2 pins to ground. Pulling the SEL pin
high activates the FB1 pin which maintains a 1.2V
reference voltage, while the FB2 reference is disabled. Pulling the SEL pin low activates the FB2
pin which maintains a 0.6V reference, while the
FB1 reference is disabled.
The AAT1230/1230-1 output voltage can be programmed by one of three methods. First, the output voltage can be static by pulling the SEL logic
pin either high or low. Second, the output voltage
can be dynamically adjusted between two pre-set
levels within a 2X operating range by toggling the
SEL logic pin. Third, the output can be dynamically adjusted to any of 16 preset levels within a 2X
operating range using the integrated S2Cwire single wire interface via the EN/SET pin.
Option 1: Static Output Voltage
A static output voltage can be configured by pulling
the SEL either high or low. SEL pin high activates the
FB1 reference pin to 1.2V (nominal). Alternatively,
the SEL pin is pulled low to activate the FB2 reference at 0.6V (nominal). Table 1 provides details of
resistor values for common output voltages from 10V
to 18V for SEL = High and SEL = Low options.
FB1 and FB2 pins is not required. See Table 1 for
static output voltages with SEL = High or SEL =
Low. SEL = High corresponds to VOUT(1) and SEL =
Low corresponds to VOUT(2).
Option 2: Dynamic Voltage Control Using SEL Pin
The output may be dynamically adjusted between
two output voltages by toggling the SEL logic pin.
Output voltages VOUT(1) and VOUT(2) correspond to
the two output references, FB1 and FB2. Pulling
the SEL logic pin high activates VOUT(1), while
pulling the SEL logic pin low activates VOUT(2).
The minimum output voltage must be greater than
the specified maximum input voltage plus margin to
maintain proper operation of the AAT1230/1230-1
boost converter. In addition, the ratio of output voltages VOUT(2)/VOUT(1) is always less than 2.0, corresponding to a 2X (maximum) programmable range.
See Table 1 for dynamic output voltage settings
when toggling between SEL = High and SEL = Low.
SEL = High corresponds to VOUT(1) and SEL = Low
corresponds to VOUT(2).
R3 = 4.99kΩ
VOUT(1)
VOUT(2)
(SEL = High) (SEL = Low) R1 (kΩ) R2 (kΩ)
10.0V
12.0V
15.0V
16.0V
18.0V
–
–
–
–
–
12.0V
15.0V
16.0V
18.0V
15.0V
16.0V
18.0V
18.0V
–
–
–
–
–
10.0V
12.0V
15.0V
16.0V
18.0V
10.0V
10.0V
10.0V
10.0V
12.0V
12.0V
12.0V
15.0V
36.5
44.2
57.6
61.9
69.8
78.7
95.3
121
127
143
75
76.8
76.8
78.7
90.9
93.1
93.1
115
0
0
0
0
0
0
0
0
0
0
3.32
1.65
1.24
0.562
3.01
2.49
1.65
3.32
Table 1: SEL Pin Voltage Control Resistor
Values (1% resistor tolerance).
In the static configuration, the FB1 pin should be
directly connected to FB2. The resistor between
1230.2007.06.1.6
13
AAT1230/1230-1
18V 100mA Step-Up Converter
Option 3: Dynamic Voltage Control Using
S2Cwire Interface
abled, the register is reset to the default value, which
sets the FB2 pin to 0.6V if EN is subsequently pulled
high.
The output can be dynamically adjusted by the host
controller to any of 16 pre-set output voltage levels
using the integrated S2Cwire interface. The
EN/SET pin serves as the S2Cwire interface input.
The SEL pin must be pulled low when using the
S2Cwire interface.
S2Cwire Output Voltage Programming
The AAT1230/1230-1 is programmed through the
S2Cwire interface according to Table 2. The rising
clock edges received through the EN/SET pin
determine the feedback reference and output voltage set-point. Upon power up with the SEL pin
low and prior to S2Cwire programming, the default
feedback reference voltage is set to 0.6V.
S2Cwire Serial Interface
AnalogicTech's S2Cwire serial interface is a proprietary high-speed single-wire interface available
only from AnalogicTech. The S2Cwire interface
records rising edges of the EN/SET input and
decodes into 16 different states. Each state corresponds to a voltage setting on the FB2 pin, as
shown in Table 2.
S2Cwire Serial Interface Timing
The S2Cwire serial interface has flexible timing.
Data can be clocked-in at speeds up to 1MHz. After
data has been submitted, EN/SET is held high to
latch the data for a period TLAT. The output is subsequently changed to the predetermined voltage.
When EN/SET is set low for a time greater than
TOFF, the AAT1230/1230-1 is disabled. When dis-
EN/SET
Rising
Edges
FB2
Reference
Voltage (V)
EN/SET
Rising
Edges
FB2
Reference
Voltage (V)
1
2
3
4
5
6
7
8
0.60 (Default)
0.64
0.68
0.72
0.76
0.80
0.84
0.88
9
10
11
12
13
14
15
16
0.92
0.96
1.00
1.04
1.08
1.12
1.16
1.20
Table 2: S2Cwire Voltage Control Settings
(SEL = Low).
THI
TLO
TOFF
T LAT
EN/SET
1
Data Reg
2
n-1
0
n ≤ 16
n-1
0
Figure 2: S2Cwire Timing Diagram to Program the Output Voltage.
14
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
PCB Layout Guidelines
Boost converter performance can be adversely
affected by poor layout. Possible impact includes
high input and output voltage ripple, poor EMI performance, and reduced operating efficiency. Every
attempt should be made to optimize the layout in
order to minimize parasitic PCB effects (stray
resistance, capacitance, inductance) and EMI coupling from the high frequency SW node.
A suggested PCB layout for the AAT1230/1230-1
boost converter is shown in Figures 3 and 4. The following PCB layout guidelines should be considered:
1. Minimize the distance from Capacitor C1 and
C2 negative terminal to the PGND pins. This
is especially true with output capacitor C2,
which conducts high ripple current from the
output diode back to the PGND pins.
2. Place the feedback resistors close to the output
terminals. Route the output pin directly to resistor R1 to maintain good output regulation. R3
should be routed close to the output GND pin,
but should not share a significant return path
with output capacitor C2.
Figure 3: AAT1230/1230-1 Evaluation
Board Top Side.
1230.2007.06.1.6
3. Minimize the distance between L1 to D1 and
switching pin SW; minimize the size of the PCB
area connected to the SW pin.
4. Maintain a ground plane and connect to the IC
RTN pin(s) as well as the GND terminals of C1
and C2.
5. Consider additional PCB area on D1 cathode
to maximize heatsinking capability. This may
be necessary when using a diode with a high
VF and/or thermal resistance.
6. When using the TDFN33-12 package, connect
paddle to SW pin or leave floating. Do not connect to RTN/GND conductors.
7. To avoid problems at startup, add a 10kΩ resistor between the VIN, VP and EN/SET pins (R4).
This is critical in applications requiring immunity from input noise during “hot plug” events, e.g.
when plugged into an active USB port.
Figure 4: AAT1230/1230-1 Evaluation
Board Bottom Side.
15
AAT1230/1230-1
18V 100mA Step-Up Converter
Boost Converter Design Example
Specification
VOUT = 16V
IOUT = 100mA
VIN
= 2.7V to 4.2V (3.6V nominal)
TAMB = 50°C
Schottky Diode
DMAX =
VO - VIN(MIN) 16 - 2.7
=
= 0.831
VIN(MIN)
2.7
IOFF(DIODE) =
IOUT
0.1A
=
= 0.592A = 592mA
1 - DMAX 1 - 0.831
For Schottky diode MBR0530, VF ≈ 0.32 @ 600mA, θJA ≈ 206°C/W in SOD-123 package.
PLOSS(DIODE) = IOUT · VF = (0.1A)(0.32V) = 0.032W = 32mW
TJ(DIODE) = TAMB + θJA · PLOSS(DIODE)
= 50 + 206 · (0.032)
= 50 + 6.6
= 56.6°C
16V Output Inductor
DMAX =
=
16
VOUT + VF - VIN(MIN)
VOUT + VF
16 + 0.32 - 2.7
= 0.834
16 + 0.32
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
From Switching Frequency vs. IOUT curves estimated switching frequency of AAT1230/1230-1 with VOUT = 16V
and IOUT = 100mA, FSW = 800kHz.
IPEAK =
=
IOUT
D
· VIN(MIN)
+ MAX
1 - DMAX
(2 · FS · L)
0.100
0.834 (2.7V)
+
1 - 0.840
2 · 0.8M · 2.2µH
= 0.625 + 0.640
= 1.265A = 1265mA
IRMS =
IPEAK
3
=
1265
3
= 730mA
For Coiltronics inductor SD3814-2R2, ISAT = 1.90A, IRMS(MAX) = 1.43A and DCR = 77mΩ.
PLOSS(INDUCTOR) = IRMS2 · DCR
= (0.730)2 (0.077)
= 0.041W
= 41mW
16V Output Capacitor
ΔVOUT = 0.1V
COUT =
IOUT · DMAX
(0.1A) (0.84)
=
(0.8kHz) (0.1V)
FS · ΔVOUT
= 1.05µF; use 2.2µF/25V MLC
1230.2007.06.1.6
17
AAT1230/1230-1
18V 100mA Step-Up Converter
AAT1230/1230-1 Losses
IRMS(ON) = IPEAK ·
= 1.270
DMAX
3
0.834
3
= 0.527A
= 527mA
IRMS(OFF) = IPEAK ·
= 1.270
(1 - DMAX)
3
0.166
3
= 0.298A
= 298mA
From datasheet curves, VIN = 3.6V, TCASE = 100°C, TSOPJW-12:
RDS(ON)L = 75mΩ, RDS(ON)IN = 220mΩ, θJA = 160°C/W.
PLOSS(RDSON) = IRMS(ON)2 · (RDS(ON)L + RDS(ON)IN) + IRMS(OFF)2 · RDS(ON)IN
= 0.5272 (0.220 + 0.075) + 0.2982 · 0.075
= 0.082 + 0.007
= 89mW
TJ(MAX) = TAMB + θJA · PLOSS(RDSON)
= 50 + 160 (0.089)
= 50 + 14.2
= 64.2°C
18
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
Manufacturer
Part Number
Rated IF(AV)
Current (A)1
Diodes, Inc.
Diodes, Inc.
Diodes, Inc.
Diodes, Inc.
ON Semi
ON Semi
Zetex
Zetex
B340LA
SD103AWS
BAT42WS
B0520WS
MBR130LSFT
MBR0530T
ZHCS350
BAT54
3.00
0.35
0.20
0.50
1.00
0.50
0.35
0.20
Rated
Voltage (V)
Thermal
Resistance
(θJA, °C/W)1
Case
40
30
30
20
30
30
40
30
25
625
625
426
325
206
330
330
SMA
SOD-323
SOD-323
SOD-323
SOD-123
SOD-123
SOD-523
SOT-23
Table 3: Typical Surface Mount Schottky Rectifiers for Various Output Loads.
(select TJ < 110°C in application circuit).
Manufacturer
Sumida
Sumida
Murata
Murata
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Taiyo Yuden
Coiltronics
Coiltronics
Coiltronics
Part Number
Inductance
(µH)
Max DC ISAT
Current (A)
DCR
(Ω)
Size (mm)
LxWxH
Type
CDR4D11/HP-2R4
CDRH4D18-2R2
LQH55DN2R2M03
LQY33PN2R2M02
NR40182R2
NR30152R2
NR40102R2
CBC3225T2R2MR
SD3814-2R2
SD3114-2R2
SD3112-2R2
2.4
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
1.70
1.32
3.20
0.72
2.70
1.48
1.15
1.13
1.90
1.48
1.12
105
75
29
360
60
60
150
80
77
86
140
4.8x4.8x1.2
5.0x5.0x2.0
5.0x5.7x4.7
3.2x3.2x0.85
4.0x4.0x1.8
3.0x3.0x1.5
4.0x4.0x1.0
3.2x2.5x2.5
3.8x3.8x1.4
3.1x3.1x1.4
3.1x3.1x1.2
Shielded
Shielded
Non-Shielded
Non-Shielded
Shielded
Shielded
Shielded
Non-Shielded
Shielded
Shielded
Shielded
Table 4: Typical Surface Mount Inductors for Various Output Loads
(select IPEAK < ISAT).
Manufacturer
Part Number
Murata
Murata
Murata
Murata
Murata
GRM188R60J475KE19D
GRM188R61A225KE34D
GRM188R61C225KA88
GRM21BR61E225KA12L
GRM188R61E105KA12D
Type
Value
(µF)
Voltage
(V)
Temp. Co.
Footprint
LxWxH (mm)
Ceramic
Ceramic
Ceramic
Ceramic
Ceramic
2.2
2.2
2.2
2.2
1.0
6.3
10
16
25
25
X5R
X5R
X5R
X5R
X5R
0603
0603
0805
0805
0603
Table 5: Typical Surface Mount Capacitors for Various Output Loads.
1. Results may vary depending on test method used and specific manufacturer.
1230.2007.06.1.6
19
AAT1230/1230-1
18V 100mA Step-Up Converter
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
TSOPJW-12
TDFN34-16
TSOPJW-12
RDXYY
RDXYY
TJXYY
AAT1230ITP-T1
AAT1230IRN-T1
AAT1230ITP-1-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Package Information3
TSOPJW-12
2.85 ± 0.20
2.40 ± 0.10
0.10
0.20 +- 0.05
0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC
7° NOM
0.04 REF
0.055 ± 0.045
0.15 ± 0.05
+ 0.10
1.00 - 0.065
0.9625 ± 0.0375
3.00 ± 0.10
4° ± 4°
0.45 ± 0.15
0.010
2.75 ± 0.25
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the
lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required
to ensure a proper bottom solder connection.
20
1230.2007.06.1.6
AAT1230/1230-1
18V 100mA Step-Up Converter
TDFN34-16
3.000 ± 0.050
1.600 ± 0.050
Detail "A"
3.300 ± 0.050
4.000 ± 0.050
Index Area
0.350 ± 0.100
Top View
0.230 ± 0.050
Bottom View
C0.3
(4x)
0.050 ± 0.050
0.450 ± 0.050
0.850 MAX
Pin 1 Indicator
(optional)
0.229 ± 0.051
Side View
Detail "A"
All dimensions in millimeters.
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work
rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent,
copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the
customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated.
All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
1230.2007.06.1.6
21