LT8330 - Low IQ Boost/SEPIC/ Inverting Converter with 1A, 60V Switch

LT8330
Low IQ Boost/SEPIC/
Inverting Converter
with 1A, 60V Switch
Description
Features
3V to 40V Input Voltage Range
nn Ultralow Quiescent Current and Low Ripple Burst
Mode® Operation: IQ = 6µA
nn 1A, 60V Power Switch
nn Positive or Negative Output Voltage Programming
with a Single Feedback Pin
nn Fixed 2MHz Switching Frequency
nn Accurate 1.6V EN/UVLO Pin Threshold
nn Internal Compensation and Soft-Start
nn Low Profile (1mm) ThinSOT™ Package
nn Low Profile (0.75mm) 8-Lead (3mm × 2mm) DFN
Package
nn
Applications
The LT®8330 is a current mode DC/DC converter capable
of generating either positive or negative output voltages
using a single feedback pin. It can be configured as a
boost, SEPIC or inverting converter consuming as low as
6µA of quiescent current. Low ripple Burst Mode operation maintains high efficiency down to very low output
currents while keeping the output ripple below 15mV in
a typical application. The internally compensated current
mode architecture results in stable operation over a wide
range of input and output voltages. Integrated soft-start
and frequency foldback functions are included to control
inductor current during start-up. The 2MHz operation
combined with small package options, enables low cost,
area efficient solutions.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Industrial and Automotive
Telecom
nn Medical Diagnostic Equipment
nn Portable Electronics
nn
nn
Typical Application
48V Boost Converter
6.8µH
4.7µF
4.7µF
SW
LT8330
1M
EN/UVLO
INTVCC
FBX
GND
4.7pF
34.8k
1µF
100
1000
90
900
80
800
70
700
60
600
50
500
40
400
30
300
200
20
EFFICIENCY
POWER LOSS
10
0
POWER LOSS (mW)
VIN
VOUT
48V
135mA
EFFICIENCY (%)
VIN
12V
Efficiency and Power Loss
0
40
80
120
LOAD CURRENT (mA)
100
0
160
8330 TA01b
8330fa
For more information www.linear.com/LT8330
1
LT8330
Absolute Maximum Ratings
(Note 1)
SW.............................................................................60V
VIN, EN/UVLO.............................................................40V
EN/UVLO Pin Above VIN Pin.........................................6V
INTVCC (Note 2)...........................................................4V
FBX............................................................................±4V
Operating Junction Temperature (Note 3)
LT8330E, LT8330I.............................. –40°C to 125°C
LT8330H............................................. –40°C to 150°C
Storage Temperature Range................... –65°C to 150°C
Pin Configuration
TOP VIEW
FBX 1
NC 2
SW 3
SW 4
9
8
EN/UVLO
7
INTVCC
6
5
TOP VIEW
SW 1
6 VIN
VIN
GND 2
5 INTVCC
GND
FBX 3
4 EN/UVLO
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
DDB PACKAGE
8-LEAD (3mm × 2mm) PLASTIC DFN
θJA = 125°C/W, θJC = 102°C/W
θJA = 60°C/W
EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB
Order Information
(http://www.linear.com/product/LT8330#orderinfo)
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT8330ES6#PBF
LT8330ES6#TRPBF
LTGMQ
6-Lead Plastic TSOT-23
–40°C to 125°C
LT8330IS6#PBF
LT8330IS6#TRPBF
LTGMQ
6-Lead Plastic TSOT-23
–40°C to 125°C
LT8330HS6#PBF
LT8330HS6#TRPBF
LTGMQ
6-Lead Plastic TSOT-23
–40°C to 150°C
LT8330EDDB#PBF
LT8330EDDB#TRPBF
LGRC
8-Lead (3mm × 2mm) Plastic DFN
–40°C to 125°C
LT8330IDDB#PBF
LT8330IDDB#TRPBF
LGRC
8-Lead (3mm × 2mm) Plastic DFN
–40°C to 125°C
LT8330HDDB#PBF
LT8330HDDB#TRPBF
LGRC
8-Lead (3mm × 2mm) Plastic DFN
–40°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
8330fa
For more information www.linear.com/LT8330
LT8330
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, EN/UVLO = 12V unless otherwise noted.
PARAMETER
CONDITIONS
MIN
VIN Operating Voltage Range
VIN Quiescent Current at Shutdown
l
VEN/UVLO = 0.2V
MAX
UNITS
40
V
l
0.9
2
2
5
µA
µA
l
2
3.6
5
9.5
µA
µA
l
5.5
8.5
10
15
µA
µA
l
780
840
1100
1200
µA
µA
1.6
–0.80
1.632
–0.780
V
V
0.005
0.005
0.015
0.015
%/V
%/V
10
nA
VEN/UVLO = 1.5V
VIN Quiescent Current
TYP
3
Sleep Mode, Not Switching
Active Mode, Not Switching
FBX Regulation
1.568
–0.820
FBX Regulation Voltage
FBX > 0V
FBX < 0V
FBX Line Regulation
FBX > 0V, 3V < VIN < 40V
FBX < 0V, 3V < VIN < 40V
FBX Pin Current
FBX = 1.6V, –0.8V
l
–10
VIN = 24V
l
1.85
l
l
Oscillator
Switching Frequency (fOSC)
2.0
2.15
MHz
Minimum On-Time
VIN = 24V
65
105
ns
Minimum Off-Time
VIN = 24V
47
65
ns
1.2
1.4
A
Switch
Maximum Switch Current Limit Threshold
l
1.0
Switch RDS(ON)
ISW = 0.5A
330
mΩ
Switch Leakage Current
VSW = 60V
0.1
1
µA
EN/UVLO Logic
EN/UVLO Pin Threshold (Rising)
Start Switching
l
1.620
1.68
1.745
V
EN/UVLO Pin Threshold (Falling)
Stop Switching
l
1.556
1.60
1.644
V
EN/UVLO Pin Current
VEN/UVLO = 1.6V
l
–40
40
nA
Soft-Start
Soft-Start Time
VIN = 24V
1
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: INTVCC cannot be externally driven. No additional components or
loading is allowed on this pin.
Note 3: The LT8330E is guaranteed to meet performance specifications
from 0°C to 125°C junction temperature. Specifications over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
ms
LT8330I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT8330H is guaranteed over the full –40°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetimes. Operating lifetime is derated at junction
temperatures greater than 125°C.
Note 4: The IC includes overtemperature protection that is intended to
protect the device during overload conditions. Junction temperature will
exceed 150°C when overtemperature protection is active. Continuous
operation above the specified maximum operating junction temperature
will reduce lifetime.
8330fa
For more information www.linear.com/LT8330
3
LT8330
Typical Performance Characteristics
FBX Positive Regulation Voltage
vs Temperature
–0.785
1.620
–0.790
1.610
–0.795
1.600
1.590
EN/UVLO Pin Thresholds
vs Temperature
1.74
VIN = 12V
1.72
EN/UVLO PIN VOLTAGE (V)
VIN = 12V
FBX VOLTAGE (V)
FBX VOLTAGE (V)
1.630
FBX Negative Regulation Voltage
vs Temperature
–0.800
–0.805
1.580
–0.810
1.570
–50 –25
–0.815
–50 –25
VIN = 12V
1.70
1.68
1.66
EN/UVLO RISING (TURN-ON)
1.64
1.62
1.60
EN/UVLO FALLING (TURN-OFF)
1.58
1.56
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8330 G01
2.04
2.02
2.00
1.98
1.96
1.94
NORMALIZED SWITCHING FREQUENCY (%)
SWITCHING FREQUENCY (MHz)
SWITCHING FREQUENCY (MHz)
Normalized Switching Frequency
vs FBX Voltage
2.15
2.06
2.10
2.05
2.00
1.95
1.90
1.92
1.90
–50 –25
1.85
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
0
5
10
8330 G04
Switch Current Limit vs Duty
Cycle
1.40
8330 G03
Switching Frequency vs VIN
VIN = 24V
2.08
15
20 25
VIN (V)
30
35
40
45
100
VIN = 12V
1.10
20
40
60
DUTY CYCLE (%)
80
100
8330 G07
4
75
50
25
0
–0.8
60
VIN = 24V
0.0
0.4
0.8
FBX VOLTAGE (V)
1.2
1.6
VIN = 24V
55
80
70
60
50
30
–50 –25
–0.4
Switch Minimum Off-Time
vs Temperature
50
45
40
35
40
0
100
8330 G06
MINIMUM OFF–TIME (ns)
MINIMUM ON–TIME (ns)
SWITCH CURRENT LIMIT (A)
1.20
VIN = 24V
8330 G05
90
1.00
125
Switch Minimum On-Time
vs Temperature
1.30
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8330 G02
Switching Frequency
vs Temperature
2.10
1.54
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8330 G08
30
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8330 G09
8330fa
For more information www.linear.com/LT8330
LT8330
Typical Performance Characteristics
1000
VIN = 12V
8.75
950
7.50
900
VIN PIN CURRENT (µA)
VIN PIN CURRENT (µA)
10.00
VIN Pin Current (Active Mode, Not
Switching) vs Temperature
6.25
5.00
3.75
2.50
1.25
Burst Frequency vs Load Current
2.5
VIN = 12V
SWITCHING FREQUENCY (MHz)
VIN Pin Current (Sleep Mode, Not
Switching) vs Temperature
850
800
750
700
FRONT PAGE APPLICATION
VIN = 12V
2.0
VOUT = 48V
1.5
1.0
0.5
650
0
–50 –25
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
600
–50 –25
0
0 25 50 75 100 125 150 175
JUNCTION TEMPERATURE (°C)
8330 G10
IL
500mA/DIV
VSW
20V/DIV
VSW
20V/DIV
8330 G13
FRONT PAGE APPLICATION
VIN = 12V, VOUT = 48V, ILOAD = 135mA
50
Switching Waveforms
(in Deep Burst Mode)
IL
500mA/DIV
1µs/DIV
20
30
40
LOAD CURRENT (mA)
8330 G12
Switching Waveforms
(in DCM/Light Burst Mode)
VSW
20V/DIV
10
8330 G11
Switching Waveforms
(in CCM)
IL
500mA/DIV
0
1µs/DIV
8330 G14
FRONT PAGE APPLICATION
VIN = 12V, VOUT = 48V, ILOAD = 20mA
1µs/DIV
FRONT PAGE APPLICATION
VIN = 12V, VOUT = 48V, ILOAD = 2mA
VOUT Transient Response: Load
Current Transients from 67.5mA to
135mA to 67.5mA
VOUT Transient Response: Load
Current Transients from 5mA to
135mA to 5mA
FRONT PAGE APPLICATION
FRONT PAGE APPLICATION
IL
100mA/DIV
8330 G15
IL
100mA/DIV
VIN = 12V
VOUT = 48V
VIN = 12V
VOUT = 48V
VOUT
500mV/DIV
VOUT
500mV/DIV
100µs/DIV
8330 G16
100µs/DIV
8330 G17
8330fa
For more information www.linear.com/LT8330
5
LT8330
Pin Functions
EN/UVLO: Shutdown and Undervoltage Detect Pin. The
LT8330 is shut down when this pin is low and active
when this pin is high. Below an accurate 1.6V threshold
the part enters undervoltage lockout and stops switching.
This allows an undervoltage lockout (UVLO) threshold to
be programmed for system input voltage by resistively
dividing down system input voltage to the EN/UVLO pin.
An 80mV pin hysteresis ensures part switching resumes
when the pin exceeds 1.68V. EN/UVLO pin voltage below
0.2V reduces VIN current below 1µA. If shutdown and
UVLO features are not required, the pin can be tied directly
to system input.
GND: Ground Connection for the LT8330. The DFN package has the best thermal performance due to an exposed
pad (Pin 9) on the bottom of the package. This exposed
pad must be soldered to a ground plane. Pin 5 of the DFN
package (and Pin 2 of the TSOT package) should also be
connected to a ground plane. The ground plane should be
connected to large copper layers to spread heat dissipated
by the LT8330.
FBX: Voltage Regulation Feedback Pin for Positive or
Negative Outputs. Connect this pin to a resistor divider
between the output and GND. FBX reduces the switching
frequency during start-up and fault conditions when FBX
is close to GND.
NC: No Internal Connection. Tie directly to local ground.
6
INTVCC: Regulated 3V Supply for Internal Loads. The
INTVCC pin must be bypassed with a minimum 1µF low ESR
ceramic capacitor to ground. No additional components
or loading is allowed on this pin.
SW: The Output of Internal Power Switch. Minimize the
metal trace area connected to this pin to reduce EMI.
VIN: Input Supply. This pin must be locally bypassed. Be
sure to place the positive terminal of the input capacitor as
close as possible to the VIN pin, and the negative terminal
as close as possible to the GND pin.
8330fa
For more information www.linear.com/LT8330
LT8330
Block Diagram
D
L
VIN
R4
OPT
R3
OPT
VOUT
CIN
COUT
EN/UVLO
VIN
SW
INTERNAL
REFERENCE
UVLO
A6
UVLO
+
–
1.68V(+)
1.6V(–)
3V REGULATOR
TJ > 170°C
INTVCC
INTVCC
UVLO
CVCC
FREQUENCY
FOLDBACK
OSCILLATOR
2MHz
VOUT
R1
1.6V
FBX
SWITCH
LOGIC
SLOPE
ERROR AMP
SELECT
BURST
DETECT
ERROR
+ AMP
A1
VC
DRIVER
–
A5
+
–
PWM COMPARATOR
R2
ERROR
–0.8V
UVLO
M1
+ AMP
A2
–
SLOPE
SOFT-START
M2
–
+
A3
+
–
A4
ILIMIT
RSENSE
GND
8330 BD
8330fa
For more information www.linear.com/LT8330
7
LT8330
Operation
The LT8330 uses a fixed frequency, current mode control
scheme to provide excellent line and load regulation. Operation can be best understood by referring to the Block
Diagram. An internal 2MHz oscillator turns on the internal
power switch at the beginning of each clock cycle. Current
in the inductor then increases until the current comparator
trips and turns off the power switch. The peak inductor
current at which the switch turns off is controlled by the
voltage on the internal VC node. The error amplifier servos
the VC node by comparing the voltage on the FBX pin with
an internal reference voltage (1.60V or –0.80V, depending
on the chosen topology). When the load current increases
it causes a reduction in the FBX pin voltage relative to
the internal reference. This causes the error amplifier to
increase the VC voltage until the new load current is satisfied. In this manner, the error amplifier sets the correct
peak switch current level to keep the output in regulation.
The LT8330 is capable of generating either a positive or
negative output voltage with a single FBX pin. It can be
configured as a boost or SEPIC converter to generate a
positive output voltage, or as an inverting converter to
generate a negative output voltage. When configured as
a boost converter, as shown in the Block Diagram, the
FBX pin is pulled up to the internal bias voltage of 1.60V
by a voltage divider (R1 and R2) connected from VOUT
to GND. Amplifier A2 becomes inactive and amplifier A1
performs (inverting) amplification from FBX to VC. When
the LT8330 is in an inverting configuration, the FBX pin
is pulled down to –0.80V by a voltage divider from VOUT
to GND. Amplifier A1 becomes inactive and amplifier A2
performs (non-inverting) amplification from FBX to VC.
If the EN/UVLO pin voltage is below 1.6V, the LT8330
enters undervoltage lockout (UVLO), and stops switching.
When the EN/UVLO pin voltage is above 1.68V (typical),
the LT8330 resumes switching. If the EN/UVLO pin voltage is below 0.2V, the LT8330 only draws 1µA from VIN.
To optimize efficiency at light loads, the LT8330 operates
in Burst Mode operation in light load situations. Between
bursts, all circuitry associated with controlling the output
switch is shut down, reducing the input supply current
to 6µA.
Applications Information
To enhance efficiency at light loads the LT8330 uses
a low ripple Burst Mode architecture. This keeps the
output capacitor charged to the desired output voltage
while minimizing the input quiescent current and output
ripple. In Burst Mode operation the LT8330 delivers single
small pulses of current to the output capacitor followed
by sleep periods where the output power is supplied by
the output capacitor. While in sleep mode the LT8330
consumes only 6µA.
As the output load decreases, the frequency of single current pulses decreases (see Figure 1) and the percentage
of time the LT8330 is in sleep mode increases, resulting
in much higher light load efficiency than for typical converters. To optimize the quiescent current performance
at light loads, the current in the feedback resistor divider
must be minimized as it appears to the output as load
current. In addition, all possible leakage currents from
8
the output should also be minimized as they all add to the
equivalent output load. The largest contributor to leakage
current can be due to the reverse biased leakage of the
Schottky diode (see Diode Selection in the Applications
Information section).
2.5
SWITCHING FREQUENCY (MHz)
Achieving Ultralow Quiescent Current
FRONT PAGE APPLICATION
VIN = 12V
2.0
VOUT = 48V
1.5
1.0
0.5
0
0
10
20
30
40
LOAD CURRENT (mA)
50
8330 F01
Figure 1. Burst Frequency vs Load Current
8330fa
For more information www.linear.com/LT8330
LT8330
Applications Information
While in Burst Mode operation the current limit of the
switch is approximately 240mA resulting in the output
voltage ripple shown in Figure 2. Increasing the output
capacitance will decrease the output ripple proportionally.
As the output load ramps upward from zero the switching frequency will increase but only up to the fixed 2MHz
defined by the internal oscillator as shown in Figure 1. The
output load at which the LT8330 reaches the fixed 2MHz
frequency varies based on input voltage, output voltage,
and inductor choice.
INTVCC Regulator
A low dropout (LDO) linear regulator, supplied from VIN,
produces a 3V supply at the INTVCC pin. A minimum 1µF
low ESR ceramic capacitor must be used to bypass the
INTVCC pin to ground to supply the high transient currents
required by the internal power MOSFET gate driver.
No additional components or loading is allowed on this
pin. The INTVCC rising threshold (to allow soft start and
switching) is typically 2.6V. The INTVCC falling threshold
(to stop switching and reset soft start) is typically 2.5V.
Duty Cycle Consideration
The LT8330 minimum on-time, minimum off-time and
switching frequency (fOSC) define the allowable minimum
and maximum duty cycles of the converter (see Minimum
On-Time, Minimum Off-Time, and Switching Frequency
in the Electrical Characteristics table).
IL
200mA/DIV
VOUT
5mV/DIV
5µs/DIV
8330 F02
Figure 2. Burst Mode Operation
Programming Input Turn-On and Turn-Off
Thresholds with EN/UVLO Pin
The EN/UVLO pin voltage controls whether the LT8330 is
enabled or is in a shutdown state. A 1.6V reference and a
comparator A6 with built-in hysteresis (typical 80mV) allow
the user to accurately program the system input voltage
at which the IC turns on and off (see the Block Diagram).
The typical input falling and rising threshold voltages can
be calculated by the following equations:
VIN(FALLING,UVLO(–)) = 1.60 • (R3+R4)/R4
VIN(RISING, UVLO(+)) = 1.68 • (R3+R4)/R4
VIN current is reduced below 1µA when the EN/UVLO pin
voltage is less than 0.2V. The EN/UVLO pin can be connected directly to the input supply VIN for always-enabled
operation. A logic input can also control the EN/UVLO pin.
When operating in Burst Mode operation for light load
currents, the current through the R3 and R4 network can
easily be greater than the supply current consumed by the
LT8330. Therefore, R3 and R4 should be large enough to
minimize their effect on efficiency at light loads.
Minimum Allowable Duty Cycle =
Minimum On-Time(MAX) • fOSC(MAX)
Maximum Allowable Duty Cycle =
1 – Minimum Off-Time(MAX) • fOSC(MAX)
The required switch duty cycle range for a Boost converter
operating in continuous conduction mode (CCM) can be
calculated as:
DMIN = 1– VIN(MAX)/(VOUT + VD)
DMAX = 1– VIN(MIN)/(VOUT + VD)
where VD is the diode forward voltage drop. If the above
duty cycle calculations for a given application violate the
minimum and/or maximum allowed duty cycles for the
LT8330, operation in discontinuous conduction mode
(DCM) might provide a solution. For the same VIN and
VOUT levels, operation in DCM does not demand as low a
duty cycle as in CCM. DCM also allows higher duty cycle
operation than CCM. The additional advantage of DCM is
the removal of the limitations to inductor value and duty
cycle required to avoid sub-harmonic oscillations and the
right half plane zero (RHPZ). While DCM provides these
benefits, the trade-off is higher inductor peak current, lower
available output power and reduced efficiency.
8330fa
For more information www.linear.com/LT8330
9
LT8330
Applications Information
Setting the Output Voltage
The output voltage is programmed with a resistor divider
from the output to the FBX pin. Choose the resistor values
for a positive output voltage according to:
IL
500mA/DIV
R1 = R2 • (VOUT /1.60V – 1)
Choose the resistor values for a negative output voltage
according to:
VOUT
20V/DIV
R1 = R2 • (|VOUT|/0.80V – 1)
500µs/DIV
The locations of R1 and R2 are shown in the Block Diagram. 1% resistors are recommended to maintain output
voltage accuracy.
Higher-value FBX divider resistors result in the lowest input
quiescent current and highest light-load efficiency. FBX
divider resistors R1 and R2 are usually in the range from
25k to 1M. Most applications use a phase-lead capacitor
from VOUT to FBX in combination with high-value FBX
divider resistors (see Compensation in the Applications
Information section).
Soft-Start
The LT8330 contains several features to limit peak switch
currents and output voltage (VOUT) overshoot during
start-up or recovery from a fault condition. The primary
purpose of these features is to prevent damage to external
components or the load.
High peak switch currents during start-up may occur in
switching regulators. Since VOUT is far from its final value,
the feedback loop is saturated and the regulator tries to
charge the output capacitor as quickly as possible, resulting
in large peak currents. A large surge current may cause
inductor saturation or power switch failure.
The LT8330 addresses this mechanism with an internal
soft-start function. As shown in the Block Diagram, the
soft-start function controls the ramp of the power switch
current by controlling the ramp of VC through M2. This
allows the output capacitor to be charged gradually toward
its final value while limiting the start-up peak currents.
Figure 3 shows the output voltage and supply current for
the first page Typical Application. It can be seen that both
the output voltage and supply current come up gradually.
10
8330 F03
Figure 3. Soft-Start Waveforms
INTVCC undervoltage (INTVCC < 2.5V) and/or thermal
lockout (TJ > 170°C) will immediately prevent switching,
will reset the internal soft-start function and will pull down
VC. Once all faults are removed, the LT8330 will soft-start
VC and hence inductor peak current.
Frequency Foldback
During start-up or fault conditions in which VOUT is very
low, extremely small duty cycles may be required to
maintain control of inductor peak current. The minimum
on-time limitation of the power switch might prevent these
low duty cycles from being achievable. In this scenario
inductor current rise will exceed inductor current fall during
each cycle, causing inductor current to ‘walk up’ beyond
the switch current limit. The LT8330 provides protection
from this by folding back switching frequency whenever
FBX pin is close to GND (low VOUT levels). This frequency
foldback provides a larger switch-off time, allowing inductor
current to fall enough each cycle (see Normalized Switching Frequency vs FBX Voltage in the Typical Performance
Characteristics section).
Thermal Lockout
If the LT8330 die temperature reaches 170°C (typical),
the part will stop switching and go into thermal lockout.
When the die temperature has dropped by 5°C (nominal),
the part will resume switching with a soft-started inductor
peak current.
8330fa
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LT8330
Applications Information
Switching Frequency and Inductor Selection
The LT8330 switches at 2MHz, allowing small value inductors to be used. 0.68µH to 10µH will usually suffice. Choose
an inductor that can handle at least 1.4A without saturating,
and ensure that the inductor has a low DCR (copper-wire
resistance) to minimize I2R power losses. Note that in
some applications, the current handling requirements of
the inductor can be lower, such as in the SEPIC topology
where each inductor only carries one-half of the total
switch current. For better efficiency, use similar valued
inductors with a larger volume. Many different sizes and
shapes are available from various manufacturers. Choose
a core material that has low losses at 2MHz, such as a
ferrite core. The final value chosen for the inductor should
not allow peak inductor currents to exceed 1A in steady
state at maximum load. Due to tolerances, be sure to account for minimum possible inductance value, switching
frequency and converter efficiency.
input voltage can ring to twice its nominal value, possibly
exceeding the LT8330’s voltage rating. This situation is
easily avoided (see Application Note 88).
Output Capacitor and Output Ripple
Low ESR (equivalent series resistance) capacitors should
be used at the output to minimize the output ripple voltage.
Multilayer ceramic capacitors are an excellent choice, as
they are small and have extremely low ESR. Use X5R or
X7R types. This choice will provide low output ripple and
good transient response. A 4.7µF to 15µF output capacitor
is sufficient for most applications, but systems with very
low output currents may need only a 1µF or 2.2µF output
capacitor. Solid tantalum or OS-CON capacitor can be
used, but they will occupy more board area than a ceramic
and will have a higher ESR. Always use a capacitor with a
sufficient voltage rating.
Compensation
Table 1. Inductor Manufacturers
Sumida
(847) 956-0666
www.sumida.com
TDK
(847) 803-6100
www.tdk.com
Murata
(714) 852-2001
www.murata.com
Coilcraft
(847) 639-6400
www.coilcraft.com
Würth
(605) 886-4385
www.we-online.com
Input Capacitor
Bypass the input of the LT8330 circuit with a ceramic capacitor of X7R or X5R type placed as close as possible to
the VIN and GND pins. Y5V types have poor performance
over temperature and applied voltage, and should not be
used. A 4.7µF to 10µF ceramic capacitor is adequate to
bypass the LT8330 and will easily handle the ripple current. If the input power source has high impedance, or
there is significant inductance due to long wires or cables,
additional bulk capacitance may be necessary. This can
be provided with a low performance electrolytic capacitor.
A precaution regarding the ceramic input capacitor concerns the maximum input voltage rating of the LT8330.
A ceramic input capacitor combined with trace or cable
inductance forms a high quality (under damped) tank circuit. If the LT8330 circuit is plugged into a live supply, the
The LT8330 is internally compensated. The decision to
use either low ESR (ceramic) capacitors or the higher
ESR (tantalum or OS-CON) capacitors, for the output
capacitor, can affect the stability of the overall system.
The ESR of any capacitor, along with the capacitance
itself, contributes a zero to the system. For the tantalum
and OS-CON capacitors, this zero is located at a lower
frequency due to the higher value of the ESR, while the
zero of a ceramic capacitor is at a much higher frequency
and can generally be ignored.
A phase lead zero can be intentionally introduced by placing
a capacitor in parallel with the resistor between VOUT and
FBX. By choosing the appropriate values for the resistor and
capacitor, the zero frequency can be designed to improve
the phase margin of the overall converter. The typical target
value for the zero frequency is between 30kHz to 60kHz.
A practical approach to compensation is to start with one
of the circuits in this data sheet that is similar to your application. Optimize performance by adjusting the output
capacitor and/or the feed forward capacitor (connected
across the feedback resistor from output to FBX pin).
8330fa
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11
LT8330
Applications Information
Ceramic Capacitors
Ceramic capacitors are small, robust and have very low
ESR. However, ceramic capacitors can cause problems
when used with the LT8330 due to their piezoelectric nature.
When in Burst Mode operation, the LT8330’s switching
frequency depends on the load current, and at very light
loads the LT8330 can excite the ceramic capacitor at audio
frequencies, generating audible noise. Since the LT8330
operates at a lower current limit during Burst Mode operation, the noise is typically very quiet to a casual ear.
If this is unacceptable, use a high performance tantalum
or electrolytic capacitor at the output. Low noise ceramic
capacitors are also available.
Table 2. Ceramic Capacitor Manufacturers
Taiyo Yuden
(408) 573-4150
www.t-yuden.com
AVX
(803) 448-9411
www.avxcorp.com
Murata
(714) 852-2001
www.murata.com
Diode Selection
A Schottky diode is recommended for use with the LT8330.
Low leakage Schottky diodes are necessary when low
quiescent current is desired at low loads. The diode leakage
appears as an equivalent load at the output and should be
minimized. Choose Schottky diodes with sufficient reverse
voltage ratings for the target applications.
Table 3. Recommended Schottky Diodes
PART NUMBER
AVERAGE
FORWARD REVERSE REVERSE
CURRENT VOLTAGE CURRENT
(mA)
(V)
(µA)
MANUFACTURER
PMEG6010CEJ
≤1000
≤60
50
NXP
PMEG6030EP
≤3000
≤60
200
NXP
Layout Hints
The high speed operation of the LT8330 demands careful attention to board layout. Careless layout will result in
performance degradation. Figure 4a shows the recommended component placement for the ThinSOT package.
Figure 4b shows the recommended component placement
for the DFN package. Note the vias under the exposed pad.
These should connect to a local ground plane for better
thermal performance.
VOUT
C4
C1
L1
D1
R1
C2
GND
1
6
2
5
3
4
GND
FB 1
8
2
7
3
6
4
5
C3
(VIN)
R3
R2
VOUT
(VIN)
C2
VIN
C1
D1
R1
C3
R4
C2
R4
FB
R3
R2
VIN
VOUT
L1
VOUT
8330 F04a
(a)
8330 F04b
(b)
Figure 4. Suggested Layout – (a) ThinSOT, (b) DFN
12
8330fa
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LT8330
Applications Information
Thermal Considerations
Care should be taken in the layout of the PCB to ensure
good heat sinking of the LT8330. The DFN package has the
best thermal performance due to an exposed pad (Pin 9)
on the bottom of the package. This exposed pad must be
soldered to a ground plane. Pin 5 of the DFN package (and
Pin 2 of the TSOT package) should also be connected to a
ground plane. The ground plane should be connected to
large copper layers to spread heat dissipated by the LT8330
and to further reduce the thermal resistance (θJA) values
listed in the Pin Configuration section. Power dissipation
within the LT8330 (PDISS_LT8330) can be estimated by
subtracting the inductor and Schottky diode power losses
from the total power losses calculated in an efficiency
measurement. The junction temperature of LT8330 can
then be estimated by,
TJ (LT8330) = TA + θJA • PDISS_LT8330
The maximum duty cycle (DMAX) occurs when the converter
operates at the minimum input voltage:
VOUT + VD
VIN(MIN) + VOUT + VD
DMAX =
Conversely, the minimum duty cycle (DMIN) occurs when
the converter operates at the maximum input voltage:
DMIN =
VOUT + VD
VIN(MAX) + VOUT + VD
Be sure to check that DMAX and DMIN obey:
DMAX < 1-Minimum Off-Time(MAX) • fOSC(MAX)
and
DMIN > Minimum On-Time(MAX) • fOSC(MAX)
Additional Topologies : SEPIC and Inverting
In addition to the Boost topology, the LT8330 can be
configured in a SEPIC or Inverting topology. SEPIC and
Inverting converters are analyzed below.
SEPIC Converter Applications
The LT8330 can be configured as a SEPIC (single-ended
primary inductance converter), as shown in Figure 5. This
topology allows for the input to be higher, equal, or lower
than the desired output voltage. The conversion ratio as
a function of duty cycle is:
voltage (VOUT), the input voltage (VIN) and the diode
forward voltage (VD).
where Minimum Off-Time, Minimum On-Time and fOSC
are specified in the Electrical Characteristics table.
SEPIC Converter: The Maximum Output Current
Capability and Inductor Selection
As shown in Figure 5, the SEPIC converter contains two
inductors: L1 and L2. L1 and L2 can be independent, but can
CDC
L1
D1
VIN
VOUT
CIN
VOUT + VD
D
=
VIN
1−D
L2
VIN
COUT
SW
LT8330
EN/UVLO
in continuous conduction mode (CCM).
In a SEPIC converter, no DC path exists between the input
and output. This is an advantage over the boost converter
for applications requiring the output to be disconnected
from the input source when the circuit is in shutdown.
INTVCC
FBX
GND
8330 F05
Figure 5. LT8330 Configured in a SEPIC Topology
SEPIC Converter: Switch Duty Cycle and Frequency
For a SEPIC converter operating in CCM, the duty cycle
of the main switch can be calculated based on the output
8330fa
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13
LT8330
Applications Information
also be wound on the same core, since identical voltages
are applied to L1 and L2 throughout the switching cycle.
For the SEPIC topology, the current through L1 is the
converter input current. Based on the fact that, ideally, the
output power is equal to the input power, the maximum
average inductor currents of L1 and L2 are:
IL1(MAX)(AVE) = IIN(MAX)(AVE) = IO(MAX) •
DMAX
1−DMAX
IL2(MAX)(AVE) = IO(MAX)
In a SEPIC converter, the switch current is equal to IL1 +
IL2 when the power switch is on, therefore, the maximum
average switch current is defined as:
ISW(MAX)(AVE) = IL1(MAX)(AVE) +IL2(MAX)(AVE)
= IO(MAX) •
1
1−DMAX
The constant c in the preceding equations represents
the percentage peak-to-peak ripple current in the switch,
relative to ISW(MAX)(AVE), as shown in Figure 6. Then, the
switch ripple current ∆ISW can be calculated by:
∆ISW = c • ISW(MAX)(AVE)
∆ISW = χ • ISW(MAX)(AVE)
Due to the current limit of its internal power switch, the
LT8330 should be used in a SEPIC converter whose
maximum output current (IO(MAX)) is less than the output
current capability by a sufficient margin (10% or higher
is recommended):
t
DTS
TS
8330 F06
Figure 6. The Switch Current Waveform of the SEPIC Converter
L1= L2 =
VIN(MIN)
0.5 • ∆ISW • fOSC
• DMAX
For most SEPIC applications, the equal inductor values
will fall in the range of 1µH to 47µH.
By making L1 = L2, and winding them on the same core, the
value of inductance in the preceding equation is replaced
by 2L, due to mutual inductance:
ISW(MAX)(AVE)
14
The inductor ripple current has a direct effect on the
choice of the inductor value. Choosing smaller values of
∆IL requires large inductances and reduces the current
loop gain (the converter will approach voltage mode).
Accepting larger values of ∆IL allows the use of low inductances, but results in higher input current ripple and
greater core losses. It is recommended that c falls in the
range of 0.2 to 0.6.
Given an operating input voltage range, and having chosen ripple current in the inductor, the inductor value (L1
and L2 are independent) of the SEPIC converter can be
determined using the following equation:
⎛ c⎞
1
ISW(PEAK) = ⎜1+ ⎟ •IO(MAX) •
⎝ 2⎠
1−DMAX
ISW
∆IL1 = ∆IL2 = 0.5 • ∆ISW
IO(MAX) < (1 – DMAX) • (1A – 0.5 • ∆ISW) • (0.9)
and the peak switch current is:
The inductor ripple currents ∆IL1 and ∆IL2 are identical:
L=
VIN(MIN)
∆ISW • fOSC
• DMAX
This maintains the same ripple current and energy storage
in the inductors. The peak inductor currents are:
IL1(PEAK) = IL1(MAX) + 0.5 • ∆IL1
IL2(PEAK) = IL2(MAX) + 0.5 • ∆IL2
The maximum RMS inductor currents are approximately
equal to the maximum average inductor currents.
8330fa
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LT8330
Applications Information
Based on the preceding equations, the user should choose
the inductors having sufficient saturation and RMS current ratings.
A low ESR and ESL, X5R or X7R ceramic capacitor works
well for CDC.
Inverting Converter Applications
SEPIC Converter: Output Diode Selection
To maximize efficiency, a fast switching diode with a low
forward drop and low reverse leakage is desirable. The
average forward current in normal operation is equal to
the output current.
It is recommended that the peak repetitive reverse voltage
rating VRRM is higher than VOUT + VIN(MAX) by a safety
margin (a 10V safety margin is usually sufficient).
The LT8330 can be configured as a dual-inductor inverting
topology, as shown in Figure 7. The VOUT to VIN ratio is:
VOUT − VD
D
=−
VIN
1−D
in continuous conduction mode (CCM).
CDC
L1
The power dissipated by the diode is:
VIN
+
PD = IO(MAX) • VD
+
CIN
SW
where VD is diode’s forward voltage drop, and the diode
junction temperature is:
LT8330
GND
TJ = TA + PD • RθJA
The RθJA used in this equation normally includes the RθJC
for the device, plus the thermal resistance from the board,
to the ambient temperature in the enclosure. TJ must not
exceed the diode maximum junction temperature rating.
SEPIC Converter: Output and Input Capacitor Selection
The selections of the output and input capacitors of the
SEPIC converter are similar to those of the boost converter.
VCDC > VIN(MAX)
CDC has nearly a rectangular current waveform. During
the switch off-time, the current through CDC is IIN, while
approximately –IO flows during the on-time. The RMS
rating of the coupling capacitor is determined by the following equation:
IRMS(CDC) > IO(MAX) •
–
COUT
D1
VOUT
+
+
8330 F07
Figure 7. A Simplified Inverting Converter
Inverting Converter: Switch Duty Cycle and Frequency
For an inverting converter operating in CCM, the duty
cycle of the main switch can be calculated based on the
negative output voltage (VOUT) and the input voltage (VIN).
The maximum duty cycle (DMAX) occurs when the converter
has the minimum input voltage:
SEPIC Converter: Selecting the DC Coupling Capacitor
The DC voltage rating of the DC coupling capacitor (CDC,
as shown in Figure 5) should be larger than the maximum
input voltage:
L2
–
DMAX =
VOUT − VD
VOUT − VD − VIN(MIN)
Conversely, the minimum duty cycle (DMIN) occurs when
the converter operates at the maximum input voltage :
DMIN =
VOUT − VD
VOUT − VD − VIN(MAX)
VOUT + VD
VIN(MIN)
8330fa
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15
LT8330
Applications Information
Be sure to check that DMAX and DMIN obey :
DMAX < 1-Minimum Off-Time(MAX) • fOSC(MAX)
and
DMIN > Minimum On-Time(MAX) • fOSC(MAX)
where Minimum Off-Time, Minimum On-Time and fOSC
are specified in the Electrical Characteristics table.
Inverting Converter: Inductor, Output Diode and Input
Capacitor Selections
The selections of the inductor, output diode and input
capacitor of an inverting converter are similar to those of
the SEPIC converter. Please refer to the corresponding
SEPIC converter sections.
Inverting Converter: Output Capacitor Selection
The inverting converter requires much smaller output
capacitors than those of the boost, flyback and SEPIC
converters for similar output ripples. This is due to the fact
that, in the inverting converter, the inductor L2 is in series
with the output, and the ripple current flowing through the
output capacitors are continuous. The output ripple voltage
is produced by the ripple current of L2 flowing through
the ESR and bulk capacitance of the output capacitor:
⎛
⎞
1
∆VOUT(P – P) = ∆IL2 • ⎜ESRCOUT +
⎟
8 • f • COUT ⎠
⎝
16
After specifying the maximum output ripple, the user can
select the output capacitors according to the preceding
equation.
The ESR can be minimized by using high quality X5R or
X7R dielectric ceramic capacitors. In many applications,
ceramic capacitors are sufficient to limit the output voltage ripple.
The RMS ripple current rating of the output capacitor
needs to be greater than:
IRMS(COUT) > 0.3 • ∆IL2
Inverting Converter: Selecting the DC Coupling
Capacitor
The DC voltage rating of the DC coupling capacitor (CDC,
as shown in Figure 7) should be larger than the maximum
input voltage minus the output voltage (negative voltage):
VCDC > VIN(MAX) – VOUT
CDC has nearly a rectangular current waveform. During
the switch off-time, the current through CDC is IIN, while
approximately –IO flows during the on-time. The RMS
rating of the coupling capacitor is determined by the following equation:
IRMS(CDC) > IO(MAX) •
DMAX
1−DMAX
A low ESR and ESL, X5R or X7R ceramic capacitor works
well for CDC.
8330fa
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LT8330
Typical Applications
48V Boost Converter
C1
4.7µF
VIN
100
D1
C3
4.7µF
SW
VOUT
48V
135mA
90
EFFICIENCY (%)
VIN
12V
L1
6.8µH
Efficiency
LT8330
R1
1M
EN/UVLO
FBX
GND
INTVCC
R2
34.8k
C2
1µF
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-MAPI 3015 74438335068
C3: MURATA GRM32ER71H475k
C4
4.7pF
80
70
60
50
8330 TA02
BOOST: VOUT = 48V
VIN = 12V
0
40
80
120
LOAD CURRENT (mA)
160
8330 TA02b
8V to 16V Input, 24V Boost Converter
100
L1
6.8µH
C1
4.7µF
R3
1M
R4
287k
VIN
D1
SW
LT8330
EN/UVLO
R1
1M
FBX
GND
INTVCC
C4
4.7pF
90
80
70
BOOST : VOUT = 24V
R2
71.5k
C2
1µF
D1: DIODES INC. SBR140S3
L1: WÜRTH WE-MAPI 3015 74438335068
C3: MURATA GRM32ER71H475k
VOUT
24V
C3
4.7µF 210mA AT VIN = 8V
320mA AT VIN = 12V
450mA AT VIN = 16V
EFFICIENCY (%)
VIN
8V TO 16V
Efficiency
60
50
8330 TA03
VIN = 8V
VIN = 12V
VIN = 16V
0
100
200
300
400
LOAD CURRENT (mA)
500
8330 TA03b
3V to 6V Input, 48V Boost Converter
100
L1
0.68µH
C1
4.7µF
VIN
D1
VOUT
48V
C3
4.7µF 12mA AT VIN = 3V
13mA AT VIN = 5V
14mA AT VIN = 6V
SW
LT8330
R1
1M
EN/UVLO
INTVCC
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-MAPI 3012 744383340068
C3: MURATA GRM32ER71H475k
C2
1µF
FBX
GND
R2
34.8k
90
80
EFFICIENCY (%)
VIN
3V TO 6V
Efficiency
70
60
50
40
30
BOOST : VOUT = 48V
20
VIN = 3V
VIN = 5V
VIN = 6V
10
8330 TA04
0
0
2
4
6
8
10 12
LOAD CURRENT (mA)
14
16
8330 TA04b
8330fa
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17
LT8330
Typical Applications
3V to 6V Input, 24V Boost Converter
100
L1
0.68µH
C1
4.7µF
VIN
D1
C3
4.7µF
SW
LT8330
EN/UVLO
80
R1
1M
FBX
GND
INTVCC
90
VOUT
24V
30mA AT V IN = 3V
34mA AT V IN = 5V
35mA AT V IN = 6V
EFFICIENCY (%)
VIN
3V TO 6V
Efficiency
60
50
R2
71.5k
C2
1µF
70
BOOST : VOUT = 24V
VIN = 3V
VIN = 5V
VIN = 6V
40
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-MAPI 3012 744383340068
C3: MURATA GRM32ER71H475k
30
8330 TA05
0
4
8
12 16 20 24 28 32 36 40
LOAD CURRENT (mA)
8330 TA05b
8V to 30V Input, 24V SEPIC Converter
VIN
8V TO 30V
C1
4.7µF
VOUT
24V
C3
4.7µF 160mA AT V IN = 8V
200mA AT V IN = 12V
×2
250mA AT V IN = 24V
250mA AT V IN = 30V
L2
6.8µH
R3
1M
VIN
SW
LT8330
EN/UVLO
R4
287k
INTVCC
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-TDC 8038 74489440068
C3: MURATA GRM32ER71H475k
18
100
D1
C2
1µF
FBX
GND
R1
1M
C4
4.7pF
90
EFFICIENCY (%)
C5
1µF
L1
6.8µH
Efficiency
80
70
SEPIC: VOUT = 24V
VIN = 8V
VIN = 12V
VIN = 24V
VIN = 30V
60
R2
71.5k
50
8330 TA06
0
60
120
180
240
LOAD CURRENT (mA)
300
8330 TA06b
8330fa
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LT8330
Typical Applications
4V to 36V Input, 12V SEPIC Converter
VIN
4V TO 36V
C1
4.7µF
100
D1
VOUT
12V
C3
4.7µF 170mA AT VIN = 4V
270mA AT VIN = 12V
×2
280mA AT VIN = 24V
280mA AT VIN = 36V
L2
4.7µH
R3
1M
R4
806k
VIN
SW
LT8330
EN/UVLO
R1
1M
FBX
GND
INTVCC
80
70
SEPIC: V OUT = 12V
VIN = 4V
VIN = 12V
VIN = 24V
VIN = 36V
60
R2
154k
C2
1µF
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-TDC 8038 74489440047
C3: MURATA GRM31CR61C475k
C4
4.7pF
90
EFFICIENCY (%)
C5
1µF
L1
4.7µH
Efficiency
50
0
60
C1
4.7µF
Efficiency
100
D1
VOUT
5V
C3
4.7µF 280mA AT VIN = 4V
300mA AT VIN = 5V
380mA AT VIN = 12V
380mA AT VIN = 16V
L2
2.7µH
R3
1M
VIN
SW
LT8330
EN/UVLO
R4
806k
INTVCC
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-TDC 8018 74489430027
C3: MURATA GRM21BR71C475k
C2
1µF
R1
1M
FBX
GND
C4
4.7pF
90
EFFICIENCY (%)
C5
1µF
L1
2.7µH
300
8330 TA07b
8330 TA07
4V to 16V Input, 5V SEPIC Converter
VIN
4V TO 16V
120
180
240
LOAD CURRENT (mA)
80
70
SEPIC: VOUT = 5V
VIN = 4V
VIN = 5V
VIN = 12V
VIN = 16V
60
R2
464k
50
0
80
160
240
320
LOAD CURRENT (mA)
400
8330 TA08b
8330 TA08
8330fa
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19
LT8330
Typical Applications
8V to 30V Input, –24V Inverting Converter
C1
4.7µF
100
L2
6.8µH
C3
2.2µF
D1
R3
1M
VIN
SW
VOUT
–24V
160mA AT VIN = 8V
200mA AT VIN = 12V
250mA AT VIN = 24V
250mA AT VIN = 30V
LT8330
EN/UVLO
R4
287k
INTVCC
R1
1M
FBX
GND
80
70
INVERTING: VOUT = –24V
VIN = 8V
VIN = 12V
VIN = 24V
VIN = 30V
60
R2
34.8k
C2
1µF
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-TDC 8038 74489440068
C3: MURATA GRM32ER71H475k
C4
4.7pF
90
EFFICIENCY (%)
VIN
8V TO 30V
C5
1µF
L1
6.8µH
Efficiency
50
0
60
C1
4.7µF
Efficiency
100
L2
4.7µH
VOUT
–12V
C3
4.7µF 170mA AT VIN = 4V
270mA AT VIN = 12V
280mA AT VIN = 24V
280mA AT VIN = 36V
D1
R3
1M
VIN
SW
LT8330
EN/UVLO
R4
806k
INTVCC
R1
1M
FBX
GND
80
70
INVERTING : VOUT = –12V
VIN=4V
VIN=12V
VIN=24V
VIN=36V
60
R2
71.5k
C2
1µF
D1: NXP PMEG6010CEJ
L1: Coilcraft LPD5030-472MR
C3: MURATA GRM21BR71C475k
C4
4.7pF
90
EFFICIENCY (%)
C5
1µF
L1
4.7µH
50
0
60
C1
4.7µF
100
L2
2.7µH
VOUT
–5V
C3
280mA AT VIN = 4V
4.7µF
300mA AT VIN = 5V
380mA AT VIN = 12V
380mA AT VIN = 16V
D1
R3
1M
VIN
SW
LT8330
EN/UVLO
R4
806k
INTVCC
D1: NXP PMEG6010CEJ
L1: WÜRTH WE-TDC 8018 74489430027
C3: MURATA GRM21BR71C475k
20
Efficiency
C2
1µF
FBX
GND
R1
1M
C4
4.7pF
90
EFFICIENCY (%)
C5
1µF
300
8330 TA10b
4V to 16V Input, –5V Inverting Converter
VIN
4V TO 16V
120
180
240
LOAD CURRENT (mA)
8330 TA10
L1
2.7µH
300
8330 TA09b
8330 TA09
4V to 36V Input, –12V Inverting Converter
VIN
4V TO 36V
120
180
240
LOAD CURRENT (mA)
80
70
INVERTING: VOUT = –5V
VIN = 4V
VIN = 5V
VIN = 12V
VIN = 16V
60
R2
191k
50
8330 TA11
0
80
160
240
320
LOAD CURRENT (mA)
400
8330 TA11b
8330fa
For more information www.linear.com/LT8330
LT8330
Package Description
Please refer to http://www.linear.com/product/LT8330#packaging for the most recent package drawings.
DDB Package
8-Lead Plastic
DFN (3mm × 2mm)
DDB Package
(Reference
LTC DWG
05-08-1702
Rev B)
8-Lead
Plastic
DFN# (3mm
× 2mm)
(Reference LTC DWG # 05-08-1702 Rev B)
0.61 ±0.05
(2 SIDES)
0.70 ±0.05
2.55 ±0.05
1.15 ±0.05
PACKAGE
OUTLINE
0.25 ±0.05
0.50 BSC
2.20 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
3.00 ±0.10
(2 SIDES)
R = 0.115
TYP
5
R = 0.05
TYP
0.40 ±0.10
8
2.00 ±0.10
(2 SIDES)
PIN 1 BAR
TOP MARK
(SEE NOTE 6)
0.56 ±0.05
(2 SIDES)
0.200 REF
0.75 ±0.05
0 – 0.05
4
0.25 ±0.05
1
PIN 1
R = 0.20 OR
0.25 × 45°
CHAMFER
(DDB8) DFN 0905 REV B
0.50 BSC
2.15 ±0.05
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
8330fa
For more information www.linear.com/LT8330
21
LT8330
Package Description
Please refer to http://www.linear.com/product/LT8330#packaging for the most recent package drawings.
S6 Package
6-Lead Plastic TSOT-23
(ReferenceS6
LTCPackage
DWG # 05-08-1636)
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
22
0.01 – 0.10
1.00 MAX
DATUM ‘A’
1.90 BSC
S6 TSOT-23 0302
8330fa
For more information www.linear.com/LT8330
LT8330
Revision History
REV
DATE
DESCRIPTION
A
03/16
Corrected VIN Quiescent Current
PAGE NUMBER
Corrected Typographic Errors
3
2, 22, 23
8330fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LT8330
23
LT8330
Typical Application
8V to 40V Input, ±15V Converter
Efficiency
C6
1µF
100
D2
L1C
6µH
L1A
6µH
VIN
8V TO 40V
C5
1µF
C1
4.7µF
R4
287k
VIN
L1B
6µH
C3
4.7µF
–VOUT
–15V
INTVCC
80
70
50
R1
1M
FBX
GND
C2
1µF
+VOUT = +15V
–VOUT = –15V
60
SW
LT8330
EN/UVLO
D1, D2: NXP PMEG6010CEJ
L1A, L1B, L1C: COILTRONICS VP4-0075
C3, C4: MURATA GRM32ER71H475k
90
120mA AT VIN = 8V
LOAD 160mA AT VIN = 24V
170mA AT VIN = 40V
D1
R3
1M
+VOUT
+15V
EFFICIENCY (%)
C4
4.7µF
VIN = 8V
VIN = 24V
VIN = 40V
0
40
80
120
160
LOAD CURRENT (mA)
200
8330 TA12b
R2
56.2k
8330 TA12
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LT1930/LT1930A
1A (ISW), 1.2MHz/2.2MHz High Efficiency Step-Up DC/DC
Converter
VIN = 2.6V to 16V, VOUT(MAX) = 34V, IQ = 4.2mA/5.5mA, ISD < 1µA,
ThinSOT Package
LT1935
2A (ISW), 40V, 1.2MHz High Efficiency Step-Up DC/DC
Converter
VIN = 2.3V to 16V, VOUT(MAX) = 38V, IQ = 3mA, ISD < 1µA,
ThinSOT Package
LT3467
1.1A (ISW), 1.3MHz High Efficiency Step-Up DC/DC
Converter
VIN = 2.4V to 16V, VOUT(MAX) = 40V, IQ = 1.2mA, ISD < 1µA,
ThinSOT, 2mm × 3mm DFN Packages
LT3580
2A (ISW), 42V, 2.5MHz, High Efficiency Step-Up DC/DC
Converter
VIN = 2.5V to 32V, VOUT(MAX) = 42V, IQ = 1mA, ISD = <1µA,
3mm × 3mm DFN-8, MSOP-8E
LT8494
70V, 2A Boost/SEPIC 1.5MHz High Efficiency Step-Up
DC/DC Converter
VIN = 1V to 60V (2.5V to 32V Start-Up), VOUT(MAX) = 70V, IQ = 3µA
(Burst Mode operation), ISD = <1µA, 20-Lead TSSOP
LT8570/LT8570-1
65V, 500mA/250mA Boost/Inverting DC/DC Converter
VIN(MIN) = 2.55V, VIN(MAX) = 40V, VOUT(MAX) = ±60V, IQ = 1.2mA,
ISD = <1mA, 3mm × 3mm DFN-8, MSOP-8E
LT8580
1A (ISW), 65V 1.5MHz, High Efficiency Step-Up DC/DC
Converter
VIN: 2.55V to 40V, VOUT(MAX) = 65V, IQ = 1.2mA, ISD = <1µA,
3mm × 3mm DFN-8, MSOP-8E
24 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LT8330
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LT8330
8330fa
LT 0316 REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2015