LT1610
1.7MHz, Single Cell
Micropower
DC/DC Converter
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FEATURES
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DESCRIPTIO
The LT®1610 is a micropower fixed frequency DC/DC
converter that operates from an input voltage as low as 1V.
Intended for small, low power applications, it switches at
1.7MHz, allowing the use of tiny capacitors and inductors.
Uses Tiny Capacitors and Inductor
Internally Compensated
Low Quiescent Current: 30µA
Operates with VIN as Low as 1V
3V at 30mA from a Single Cell
5V at 200mA from 3.3V
High Output Voltage Capability: Up to 28V
Low Shutdown Current: < 1µA
Automatic Burst ModeTM Switching at Light Load
Low VCESAT Switch: 300mV at 300mA
8-Lead MSOP and SO Packages
The device can generate 3V at 30mA from a single cell
(1V) supply. An internal compensation network can be
connected to the LT1610’s VC pin, eliminating two external components. No-load quiescent current of the LT1610
is 30µA, and the internal NPN power switch handles a
300mA current with a voltage drop of 300mV.
The LT1610 is available in 8-lead MSOP and SO packages.
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APPLICATIO S
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Pagers
Cordless Phones
Battery Backup
LCD Bias
Portable Electronic Equipment
, LTC and LT are registered trademarks of Linear Technology Corporation.
Burst Mode is a trademark of Linear Technology Corporation.
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TYPICAL APPLICATIO
D1
6
3
+
1 CELL
C1
22µF
FB
SHDN
GND
PGND
1
4
VIN = 1.25V
VIN = 1.5V
75
R2
681k
COMP
VC
VOUT = 3V
80
2
LT1610
8
85
R1
1M
5
SW
VIN
Efficiency
VOUT
3V
30mA
+
7
C2
22µF
EFFICIENCY (%)
L1
4.7µH
70
VIN = 1V
65
60
55
C1, C2: AVX TAJA226M006R
D1: MOTOROLA MBR0520
L1: MURATA LQH1C4R7
Figure 1. 1-Cell to 3V Step-Up Converter
1610 F01
50
0.1
1
10
LOAD CURRENT (mA)
100
1610 TA01
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LT1610
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ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN Voltage ................................................................ 8V
SW Voltage ............................................... – 0.4V to 30V
FB Voltage ..................................................... VIN + 0.3V
VC Voltage ................................................................ 2V
COMP Voltage .......................................................... 2V
Current into FB Pin .............................................. ±1mA
SHDN Voltage ............................................................ 8V
Maximum Junction Temperature ......................... 125°C
Operating Temperature Range (Note 1)
Commercial ............................................. 0°C to 70°C
Extended Commercial (Note 2) .......... – 40°C to 85°C
Industrial ........................................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
VC
FB
SHDN
PGND
1
2
3
4
8
7
6
5
COMP
GND
VIN
SW
LT1610CMS8
MS8 PACKAGE
8-LEAD PLASTIC MSOP
MS8 PART MARKING
TJMAX = 125°C, θJA = 160°C/W
LTDT
ORDER PART
NUMBER
TOP VIEW
VC 1
8
COMP
FB 2
7
GND
SHDN 3
6
VIN
PGND 4
5
SW
LT1610CS8
LT1610IS8
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1610
1610I
TJMAX = 125°C, θJA = 120°C/W
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the specified temperature
range, otherwise specifications are at TA = 25°C. Commercial grade 0°C to 70°C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted.
(Note 2)
PARAMETER
CONDITIONS
MIN
Minimum Operating Voltage
TYP
0.9
Maximum Operating Voltage
Feedback Voltage
●
Quiescent Current
VSHDN = 1.5V, Not Switching
Quiescent Current in Shutdown
VSHDN = 0V, VIN = 2V
VSHDN = 0V, VIN = 5V
FB Pin Bias Current
Reference Line Regulation
Error Amp Transconductance
1.20
●
1V ≤ VIN ≤ 2V (25°C, 0°C)
1V ≤ VIN ≤ 2V (70°C)
2V ≤ VIN ≤ 8V (25°C, 0°C)
2V ≤ VIN ≤ 8V (70°C)
∆I = 2µA
1
V
8
V
1.26
V
30
60
µA
0.5
1.0
µA
µA
27
80
nA
0.6
1
2
0.15
0.2
%/V
%/V
%/V
%/V
25
µmhos
100
V/V
●
1.4
1.7
2
MHz
80
●
77
75
95
95
%
%
Maximum Duty Cycle
2
UNITS
0.01
0.01
0.03
Error Amp Voltage Gain
Switching Frequency
1.23
MAX
LT1610
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the specified temperature
range, otherwise specifications are at TA = 25°C. Commercial grade 0°C to 70°C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted.
(Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Switch Current Limit
(Note 3)
450
600
900
mA
Switch VCESAT
ISW = 300mA
300
350
400
mV
mV
0.01
1
µA
●
Switch Leakage Current
VSW = 5V
SHDN Input Voltage High
1
V
SHDN Input Voltage Low
SHDN Pin Bias Current
VSHDN = 3V
VSHDN = 0V
10
0.01
0.3
V
0.1
µA
µA
The ● denotes specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C.
Industrial grade – 40°C to 85°C, VIN = 1.5V, VSHDN = VIN, unless otherwise noted.
PARAMETER
CONDITIONS
Minimum Operating Voltage
TA = 85°C
TA = – 40°C
MIN
TYP
MAX
UNITS
0.9
1
1.25
V
V
8
V
1.26
V
Maximum Operating Voltage
Feedback Voltage
●
1.20
Quiescent Current
Quiescent Current in Shutdown
VSHDN = 0V, VIN = 2V
VSHDN = 0V, VIN = 5V
FB Pin Bias Current
●
Reference Line Regulation
2V ≤ VIN ≤ 8V (– 40°C)
2V ≤ VIN ≤ 8V (85°C)
Error Amp Transconductance
∆I = 2µA
30
60
µA
0.01
0.01
0.5
1.0
µA
µA
27
80
nA
0.03
0.15
0.2
%/V
%/V
100
Switching Frequency
(Note 4)
Maximum Duty Cycle
(Note 4)
1.4
1.7
2
MHz
77
75
80
●
95
95
%
%
450
600
900
mA
300
350
400
mV
mV
0.01
1
µA
ISW = 300mA
●
VSW = 5V
SHDN Input Voltage High
1
V
SHDN Input Voltage Low
SHDN Pin Bias Current
V/V
●
Switch Current Limit
Switch Leakage Current
µmhos
25
Error Amp Voltage Gain
Switch VCESAT
1.23
VSHDN = 3V
VSHDN = 0V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1610C is guaranteed to meet specified performance from
0°C to 70°C and is designed, characterized and expected to meet these
extended temperature limits, but is not tested at – 40°C and 85°C. The
LT1610I is guaranteed to meet the extended temperature limits.
10
0.01
0.3
V
0.1
µA
µA
Note 3: Current limit guaranteed by design and/or correlation to static test.
Current limit is affected by duty cycle due to ramp generator. See Block
Diagram.
Note 4: Not 100% tested at 85°C.
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LT1610
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TYPICAL PERFOR A CE CHARACTERISTICS
Current Limit (DC = 30%)
vs Temperature
VCESAT vs Current
600
Current Limit vs Duty Cycle
800
800
500
VCESAT (mV)
TA = 85°C
400
TA = 25°C
300
TA = – 40°C
200
100
0
500
200
300
400
SWITCH CURRENT (mA)
100
700
CURRENT LIMIT (mA)
SWITCH CURRENT LIMIT (mA)
TA = 25°C
700
600
500
400
300
0
25
50
TEMPERATURE (°C)
75
0
1.50
1.25
1.00
0.75
0.50
40
35
1.230
1.225
1.220
1.215
0
6
4
3
5
INPUT VOLTAGE (V)
7
1.210
–50
8
30
25
20
15
10
5
0.25
2
80 90 100
Quiescent Current
vs Temperature
QUIESCENT CURRENT (µA)
1.75
10 20 30 40 50 60 70
DUTY CYCLE (%)
1610 G03
1.235
FEEDBACK VOLTAGE (V)
SWITCHING FREQUENCY (MHz)
100
1.240
2.00
1
200
Feedback Voltage
TA = 25°C
0
300
1610 G02
Oscillator Frequency
vs Input Voltage
2.50
400
0
–25
1610 G01
2.25
500
100
200
–50
600
600
–25
0
25
50
TEMPERATURE (°C)
75
100
0
– 50
– 25
0
50
25
TEMPERATURE (°C)
1610 G05
1610 G04
SHDN Pin Current
vs SHDN Pin Voltage
75
100
1610 G06
Burst Mode Operation,
Circuit of Figure 1
Transient Response,
Circuit of Figure 1
SHDN CURRENT (µA)
50
40
VOUT
50mV/DIV
AC COUPLED
30
IL1
100mA/DIV
ILOAD
20
SWITCH
VOLTAGE
2V/DIV
SWITCH
CURRENT
50mA/DIV
31mA
1mA
VIN = 1.25V
VOUT = 3V
10
0
0
1
2
4
3
5
6
SHDN VOLTAGE (V)
7
8
1610 G07
4
VOUT
20mV/DIV
AC COUPLED
500µs/DIV
1610 TA08
VIN = 1.25V
VOUT = 3V
ILOAD = 3mA
20µs/DIV
1610 TA08
LT1610
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PIN FUNCTIONS
VC (Pin 1): Error Amplifier Output. Frequency compensation network must be connected to this pin, either internal
(COMP pin) or external series RC to ground. 220kΩ/
220pF typical value.
FB (Pin 2): Feedback Pin. Reference voltage is 1.23V.
Connect resistive divider tap here. Minimize trace area at
FB. Set VOUT according to VOUT = 1.23V (1 + R1/R2).
SHDN (Pin 3): Shutdown. Ground this pin to turn off
device. Tie to 1V or more to enable.
SW (Pin 5): Switch Pin. Connect inductor/diode here.
Minimize trace area at this pin to keep EMI down.
VIN (Pin 6): Input Supply Pin. Must be locally bypassed.
GND (Pin 7): Signal Ground. Carries all device ground
current except switch current. Tie to local ground plane.
COMP (Pin 8): Internal Compensation Network. Tie to VC
pin, or let float if external compensation is used. Output
capacitor must be tantalum if COMP pin is used for compensation.
PGND (Pin 4): Power Ground. Tie directly to local ground
plane.
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BLOCK DIAGRA
VIN
6
VIN
R5
40k
VOUT
R6
40k
+
A1
gm
R1
(EXTERNAL)
FB
FB
2
R2
(EXTERNAL)
1 VC
–
8
Q1
Q2
× 10
SHUTDOWN
COMP
3 SHDN
7 GND
RC
CC
R3
30k
R4
140k
+
ENABLE
–
BIAS
5 SW
–
RAMP
GENERATOR
COMPARATOR
FF
Σ
+
A2
R
DRIVER
Q3
Q
S
+
0.15Ω
A=3
1.7MHz
OSCILLATOR
–
4
PGND
1610 F02
Figure 2. LT1610 Block Diagram
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LT1610
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APPLICATIONS INFORMATION
OPERATION
The LT1610 combines a current mode, fixed frequency
PWM architecture with Burst Mode micropower operation
to maintain high efficiency at light loads. Operation can be
best understood by referring to the block diagram in
Figure 2. Q1 and Q2 form a bandgap reference core whose
loop is closed around the output of the converter. When
VIN is 1V, the feedback voltage of 1.23V, along with an
70mV drop across R5 and R6, forward biases Q1 and Q2’s
base collector junctions to 300mV. Because this is not
enough to saturate either transistor, FB can be at a higher
voltage than VIN. When there is no load, FB rises slightly
above 1.23V, causing VC (the error amplifier’s output) to
decrease. When VC reaches the bias voltage on hysteretic
comparator A1, A1’s output goes low, turning off all
circuitry except the input stage, error amplifier and lowbattery detector. Total current consumption in this state is
30µA. As output loading causes the FB voltage to decrease, A1’s output goes high, enabling the rest of the IC.
Switch current is limited to approximately 100mA initially
after A1’s output goes high. If the load is light, the output
voltage (and FB voltage) will increase until A1’s output
goes low, turning off the rest of the LT1610. Low frequency ripple voltage appears at the output. The ripple
frequency is dependent on load current and output capacitance. This Burst Mode operation keeps the output regulated and reduces average current into the IC, resulting in
high efficiency even at load currents of 1mA or less.
If the output load increases sufficiently, A1’s output remains
high, resulting in continuous operation. When the LT1610
is running continuously, peak switch current is controlled
by VC to regulate the output voltage. The switch is turned
on at the beginning of each switch cycle. When the summation of a signal representing switch current and a ramp
generator (introduced to avoid subharmonic oscillations at
duty factors greater than 50%) exceeds the VC signal,
comparator A2 changes state, resetting the flip-flop and
turning off the switch. Output voltage increases as switch
current is increased. The output, attenuated by a resistor
divider, appears at the FB pin, closing the overall loop.
Frequency compensation is provided by either an external
series RC network connected between the VC pin and
ground or the internal RC network on the COMP pin (Pin
8). The typical values for the internal RC are 50k and 50pF.
LAYOUT
Although the LT1610 is a relatively low current device, its
high switching speed mandates careful attention to layout
for optimum performance. For boost converters, follow
the component placement indicated in Figure 3 for the best
results. C2’s negative terminal should be placed close to
Pin 4 of the LT1610. Doing this reduces switching currents
in the ground copper which keeps high frequency “spike”
noise to a minimum. Tie the local ground into the system
ground plane at one point only, using a few vias, to avoid
introducing dI/dt induced noise into the ground plane.
GROUND PLANE
R1
R2
SHUTDOWN
VIN
1
8
2
7
LT1610
3
6
4
5
+
L1
+
MULTIPLE
VIAs
GND
C1
D1
C2
VOUT
1610 F03
Figure 3. Recommended Component Placement for Boost Converter. Note Direct High Current Paths Using
Wide PC Traces. Minimize Trace Area at Pin 1 (VC) and Pin 2 (FB). Use Multiple Vias to Tie Pin 4 Copper to
Ground Plane. Use Vias at One Location Only to Avoid Introducing Switching Currents into the Ground Plane
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LT1610
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APPLICATIONS INFORMATION
A SEPIC (Single-Ended Primary Inductance Converter)
schematic is shown in Figure 4. This converter topology
produces a regulated output over an input voltage range
that spans (i.e., can be higher or lower than) the output.
Recommended component placement for a SEPIC is
shown in Figure 5.
C3
1µF
CERAMIC
L1
22µH
INPUT
Li-ION
3V to 4.2V
6
VIN
+
1
C1
22µF
6.3V
5
SW
VC
FB
1M
COMP
•
+
604k
SHDN
GND
PGND
7
4
VOUT
3.3V
120mA
L2
22µH
2
LT1610
8
D1
•
3
C2
22µF
6.3V
C1, C2: AVX TAJA226M006
C3: AVX 1206YC105 (X7R)
SHUTDOWN
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220 (UNCOUPLED)
OR SUMIDA CLS62-220 (COUPLED)
1610 F04
Figure 4. Li-Ion to 3.3V SEPIC DC/DC Converter
GROUND PLANE
R1
R2
SHUTDOWN
MULTIPLE
VIAs
VIN
1
8
2
7
LT1610
3
6
4
5
C2
C1
+
L1
L2
C3
+
GND
D1
VOUT
1610 F05
Figure 5. Recommended Component Placement for SEPIC
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LT1610
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COMPONENT SELECTION
Inductors
Inductors used with the LT1610 should have a saturation
current rating (–30% of zero current inductance) of approximately 0.5A or greater. DCR should be 0.5Ω or less.
The value of the inductor should be matched to the power
requirements and operating voltages of the application. In
most cases a value of 4.7µH or 10µH is suitable. The Murata
LQH3C inductors specified throughout the data sheet are
small and inexpensive, and are a good fit for the LT1610.
Alternatives are the CD43 series from Sumida and the
DO1608 series from Coilcraft. These inductors are slightly
larger but will result in slightly higher circuit efficiency.
Chip inductors, although tempting to use because of their
small size and low cost, generally do not have enough
energy storage capacity or low enough DCR to be used
successfully with the LT1610.
Diodes
The Motorola MBR0520 is a 0.5 amp, 20V Schottky diode.
This is a good choice for nearly any LT1610 application,
unless the output voltage or the circuit topology require a
diode rated for higher reverse voltages. Motorola also
offers the MBR0530 (30V) and MBR0540 (40V) versions.
Most one-half amp and one amp Schottky diodes are
suitable; these are available from many manufacturers. If
you use a silicon diode, it must be an ultrafast recovery
type. Efficiency will be lower due to the silicon diode’s
higher forward voltage drop.
Capacitors
The input capacitor must be placed physically close to the
LT1610. ESR is not critical for the input. In most cases
inexpensive tantalum can be used.
The choice of output capacitor is far more important. The
quality of this capacitor is the greatest determinant of the
output voltage ripple. The output capacitor performs two
major functions. It must have enough capacitance to
satisfy the load under transient conditions and it must
shunt the AC component of the current coming through
the diode from the inductor. The ripple on the output
results when this AC current passes through the finite
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impedance of the output capacitor. The capacitor should
have low impedance at the 1.7MHz switching frequency of
the LT1610. At this frequency, the impedance is usually
dominated by the capacitor’s equivalent series resistance
(ESR). Choosing a capacitor with lower ESR will result in
lower output ripple.
Perhaps the best way to decrease ripple is to add a 1µF
ceramic capacitor in parallel with the bulk output capacitor. Ceramic capacitors have very low ESR and 1µF is
enough capacitance to result in low impedance at the
switching frequency. The low impedance can have a
dramatic effect on output ripple voltage. To illustrate,
examine Figure 6’s circuit, a 4-cell to 5V/100mA SEPIC
DC/DC converter. This design uses inexpensive aluminum
electrolytic capacitors at input and output to keep cost
down. Figure 7 details converter operation at a 100mA
load, without ceramic capacitor C5. Note the 400mV
spikes on VOUT.
After C5 is installed, output ripple decreases by a factor of
8 to about 50mVP-P. The addition of C5 also improves
efficiency by 1 to 2 percent.
Low ESR and the required bulk output capacitance can be
obtained using a single larger output capacitor. Larger
tantalum capacitors, newer capacitor technologies (for
example the POSCAP from Sanyo and SPCAP from
Panasonic) or large value ceramic capacitors will reduce
the output ripple. Note, however, that the stability of the
circuit depends on both the value of the output capacitor
and its ESR. When using low value capacitors or capacitors with very low ESR, circuit stability should be evaluated carefully, as described below.
Loop Compensation
The LT1610 is a current mode PWM switching regulator
that achieves regulation with a linear control loop. The
LT1610 provides the designer with two methods of compensating this loop. First, you can use an internal compensation network by tying the COMP pin to the VC pin. This
results in a very small solution and reduces the circuit’s
total part count. The second option is to tie a resistor RC
and a capacitor CC in series from the VC pin to ground. This
allows optimization of the transient response for a wide
variety of operating conditions and power components.
LT1610
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APPLICATIONS INFORMATION
L1
22µH
•
6
VIN
+
4 CELLS
C1
22µF
6.3V
C4
1µF
CERAMIC
1
C3
1µF
CERAMIC
5
SW
VC
1M
FB
COMP
324k
SHDN
GND
PGND
7
4
C1, C2: ALUMINUM ELECTROLYTIC
C3 TO C5: CERAMIC X7R OR X5R
D1: MBR0520
L1, L2: MURATA LQH3C220 OR SUMIDA CLS62-220
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VOUT
5V
120mA
•
L2
22µH
2
LT1610
8
D1
+
C2
22µF
6.3V
C5
1µF
CERAMIC
1610 F06
SHUTDOWN
Figure 6. 4-Cell Alkaline to 5V/120mA SEPIC DC/DC Converter
sation network is modified to achieve stable operation.
Linear Technology’s Application Note 19 contains a detailed description of the method. A good starting point for
the LT1610 is CC ~ 220pF and RC ~ 220k.
VOUT
200mV/DIV
IDIODE
500mA/DIV
SWITCH
VOLTAGE
10V/DIV
All Ceramic, Low Profile Design
100ns/DIV
1610 F07
Figure 7. Switching Waveforms Without Ceramic Capacitor C5
VOUT
50mV/DIV
IDIODE
500mA/DIV
SWITCH
VOLTAGE
10V/DIV
VIN = 4.1V
LOAD = 100mA
100ns/DIV
1610 F08
Figure 8. Switching Waveforms with Ceramic Capacitor C5.
Note the 50mV/DIV Scale for VOUT
It is best to choose the compensation components empirically. Once the power components have been chosen
(based on size, efficiency, cost and space requirements),
a working circuit is built using conservative (or merely
guessed) values of RC and CC. Then the response of the
circuit is observed under a transient load, and the compen-
Large value ceramic capacitors that are suitable for use as
the main output capacitor of an LT1610 regulator are now
available. These capacitors have very low ESR and therefore offer very low output ripple in a small package.
However, you should approach their use with some
caution.
Ceramic capacitors are manufactured using a number of
dielectrics, each with different behavior across temperature and applied voltage. Y5V is a common dielectric used
for high value capacitors, but it can lose more than 80% of
the original capacitance with applied voltage and extreme
temperatures. The transient behavior and loop stability of
the switching regulator depend on the value of the output
capacitor, so you may not be able to afford this loss. Other
dielectrics (X7R and X5R) result in more stable characteristics and are suitable for use as the output capacitor. The
X7R type has better stability across temperature, whereas
the X5R is less expensive and is available in higher values.
The second concern in using ceramic capacitors is that
many switching regulators benefit from the ESR of the
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LT1610
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APPLICATIONS INFORMATION
output capacitor because it introduces a zero in the
regulator’s loop gain. This zero may not be effective
because the ceramic capacitor’s ESR is very low. Most
current mode switching regulators (including the LT1610)
can easily be compensated without this zero. Any design
should be tested for stability at the extremes of operating
temperatures; this is particularly so of circuits that use
ceramic output capacitors.
Figure 9 details a 2.5V to 5V boost converter. Transient
response to a 5mA to 105mA load step is pictured in Figure
10. The “double trace” of VOUT at 105mA load is due to the
ESR of C2. This ESR aids stability. In Figure 11, C2 is
replaced by a 10µF ceramic capacitor. Note the low phase
margin; at higher input voltage, the converter may oscillate. After replacing the internal compensation network
with an external 220pF/220k series RC, the transient
response is shown in Figure 12. This is acceptable transient response.
VOUT
100mV/DIV
LOAD
CURRENT
105mA
5mA
500µs/DIV
Figure 10. Tantalum Output Capacitor
and Internal RC Compensation
VOUT
100mV/DIV
LOAD
CURRENT
105mA
5mA
500µs/DIV
Table 1
FIGURE
C2
COMPENSATION
10
AVX TAJA226M006 Tantalum
11
Taiyo Yuden JMK316BJ106
Internal
12
Taiyo Yuden JMK316BJ106
220pF/220k
L1
10µH
VIN
2.5V
5
SW
VIN
3
+
C1
22µF
FB
SHDN
RC
VC
GND
COMP
8
VOUT
5V
100mA
2
7
R2
324k
+
PGND
4
1610 F09
Figure 9. 2.5V to 5V Boost Converter Can Operate with a
Ceramic Output Capacitor as Long as Proper RC and CC
are Used. Disconnect COMP Pin if External Compensation
Components Are Used
10
LOAD
CURRENT
105mA
5mA
500µs/DIV
C2
22µF
CC
C1: AVX TAJA226M006
C2: SEE TABLE
D1: MOTOROLA MBR0520
L1: MURATA LQH30100
Figure 11. 10µF X5R-Type Ceramic Output Capacitor
and Internal RC Compensation has Low Phase Margin
VOUT
100mV/DIV
1M
LT1610
1
1610 F11
Internal
D1
6
1610 F10
1610 F12
Figure 12. Ceramic Output Capacitor with 220pF/220k
External Compensation has Adequate Phase Margin
LT1610
U
TYPICAL APPLICATIONS
2-Cell to 5V Converter
6
VIN
3
+
2 CELLS
C1
15µF
90
D1
VOUT
5V
50mA
5
SW
1M
2
FB
SHDN
LT1610
8
324k
COMP
VC
PGND
1
4
+
7
GND
C2
15µF
VIN = 3V
VIN = 2V
80
EFFICIENCY (%)
L1
4.7µH
Efficiency
VIN = 1.5V
70
60
50
C1, C2: AVX TAJA156M010R
D1: MOTOROLA MBR0520
L1: SUMIDA CD43-4R7
MURATA LQH1C4R7
0.1
1
1610 TA02
1
2 CELLS
Efficiency
90
D1
6
5
VIN
SW
2
R3
604k
LT1610
8
COMP
SHDN
GND
PGND
7
4
C1: AVX TAJA106M010R
C2: AVX TAJB336M006R
D1: MBR0520
L1: MURATA LQH3C4R7
3
3.3VOUT
3VIN
80
R2
1M
FB
VC
VOUT
3.3V
70mA
+
C2
33µF
EFFICIENCY (%)
L1
4.7µH
C1
10µF
2VIN
60
50
0.1
1610 TA04
SHUTDOWN
100
1000
90
D1
6
5
VIN
SW
FB
VC
COMP
SHDN
GND
PGND
7
4
VOUT
12V
100mA
R2
1M
2
LT1610
8
10
LOAD (mA)
Efficiency
3
R3
115k
+
C2
15µF
85
80
EFFICIENCY (%)
VIN
5V
C1
15µF
1
1610 TA05
L1
10µH
+
1.5VIN
70
5V to 12V/100mA Boost Converter
1
1000
1610 TA03
2-Cell to 3.3V Converter
+
100
10
LOAD CURRENT (mA)
75
70
65
60
55
50
0.1
C1: AVX TAJA156M010
C2: AVX TAJB156M016
D1: MOTOROLA MBR0520
L1: MURATA LQH3C100M24
1610 TA06
SHUTDOWN
1
10
LOAD CURRENT (mA)
100
1610 TA07
11
LT1610
U
TYPICAL APPLICATIONS
5V to 9V/150mA Boost Converter
VIN
5V
1
+
C1
15µF
6
5
VIN
SW
FB
VC
COMP
SHDN
GND
PGND
7
4
VOUT
9V
150mA
2
3
R3
158k
85
80
R2
1M
LT1610
8
90
D1
+
C2
15µF
EFFICIENCY (%)
L1
10µH
Efficiency
75
70
65
60
55
50
C1: AVX TAJA156M010
C2: AVX TAJB156M016
D1: MOTOROLA MBR0520
L1: MURATA LQH3C100M24
1
1610 TA08
SHUTDOWN
300
1610 TA09
5V to 9V Boost Converter Transient Response
VOUT
200mV/DIV
LOAD
CURRENT
140mA
10mA
INDUCTOR
CURRENT
200mA/DIV
200µs/DIV
12
10
100
LOAD CURRENT (mA)
1610 TA10
LT1610
U
TYPICAL APPLICATIONS
3.3V TO 8V/70mA, – 8V/5mA, 24V/5mA TFT LCD Bias Supply Uses All Ceramic Capacitors
D2
VOFF
– 8V
5mA
1µF
D3
0.22µF
0.22µF
0.22µF:
1µF:
4.7µF:
D1:
D2, D3, D4:
L1:
TAIYO YUDEN EMK212BJ224MG
TAIYO YUDEN LMK212BJ105MG
TAIYO YUDEN LMK316BJ475ML
MOTOROLA MBRO520
BAT54S
SUMIDA CDRH5D185R4
D4
0.22µF
L1
5.4µH
VIN
3.3V
1µF
D1
6
3
1µF
AVDD
8V
70mA
5
VIN
SW
COMP
SHDN
8
274k
C1
4.7µF
C2
4.7µF
LT1610
1
100k
VON
24V
5mA
FB
VC
GND
PGND
7
4
2
48.7k
51pF
1610 TA18
TFT LCD Bias Supply Transient Response
AVDD
200mV/DIV
VON
500mV/DIV
VOFF
200mV/DIV
AVDD LOAD 70mA
25mA
VON LOAD = 5mA
VOFF LOAD = 5mA
200µs/DIV
1610 TA19
13
LT1610
U
TYPICAL APPLICATIONS
Single Cell Super Cap Charger
L1
4.7µH
6
CHARGE
3
+
C1
15µF
SHUTDOWN
1 AA
ALKALINE
SW
VIN
COMP
SHDN
15k
VC
FB
GND
PGND
7
4
VOUT
4.5V
R1
200k
5
Q1
8
+
LT1610
1
R4
20Ω
D1
R2
2M
C2
15µF
+
CBIG
2
R3
845k
3.3nF
1610 TA11
C1, C2: AVX TAJA156M010
D1: MOTOROLA MBR0530T1
L1: MURATA LQH1C4R7
Q1: 2N3906
Super Cap Charger Output Current vs Output Voltage
Super Cap Charger Output Power vs Output Voltage
60
50
20
OUTPUT POWER (mW)
OUTPUT CURRENT (mA)
25
15
10
5
0
30
20
10
2.0
2.5
3.0
3.5
4.0
OUTPUT VOLTAGE (V)
4.5
5.0
1610 TA12
14
40
0
2.0
2.5
3.0
3.5
4.0
OUTPUT VOLTAGE (V)
4.5
5.0
1610 TA13
LT1610
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 ± 0.004*
(3.00 ± 0.102)
8
7 6
5
0.118 ± 0.004**
(3.00 ± 0.102)
0.192 ± 0.004
(4.88 ± 0.10)
1
4
2 3
0.040 ± 0.006
(1.02 ± 0.15)
0.007
(0.18)
0.034 ± 0.004
(0.86 ± 0.102)
0° – 6° TYP
SEATING
PLANE 0.012
(0.30)
0.0256
REF
(0.65)
TYP
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS8) 1197
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
8
7
6
5
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
0.053 – 0.069
(1.346 – 1.752)
0°– 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.014 – 0.019
(0.355 – 0.483)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
2
3
4
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
TYP
SO8 0996
15
LT1610
U
TYPICAL APPLICATIONS N
Li-Ion to 3.3V SEPIC DC/DC Converter
INPUT
Li-ION
3V to 4.2V
•
6
VIN
+
C1
22µF
6.3V
1
5
SW
VC
FB
COMP
D1
1M
GND
PGND
7
4
70
•
+
604k
SHDN
VOUT
3.3V
120mA
L2
22µH
2
LT1610
8
80
C3
1µF
CERAMIC
EFFICIENCY (%)
L1
22µH
Efficiency
3
C2
22µF
6.3V
60
50
40
30
0.1
C1, C2: AVX TAJB226M006
C3: AVX 1206YC105 (X7R)
SHUTDOWN
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220 (UNCOUPLED)
OR SUMIDA CLS62-220 (COUPLED)
1610 TA15
+
4 CELLS
C1
22µF
6.3V
1
5
SW
VC
FB
8
COMP
D1
1M
GND
PGND
7
4
70
•
324k
SHDN
VOUT
5V
120mA
L2
22µH
2
LT1610
4-Cell to 5V Efficiency
EFFICIENCY (%)
6
VIN
100
80
C3
1µF
CERAMIC
•
1
10
LOAD CURRENT (mA)
1610 TA14
4-Cell to 5V/120mA SEPIC DC/DC Converter
L1
22µH
VIN = 2.7V
VIN = 3.6V
VIN = 4.2V
+
3
C2
22µF
6.3V
C1, C2: AVX TAJB226M006
C3: AVX 1206YC105 (X7R)
SHUTDOWN
D1: MOTOROLA MBR0520
L1, L2: MURATA LQH3C220 (UNCOUPLED)
OR SUMIDA CLS62-220 (COUPLED)
VIN = 3.6V
VIN = 4.2V
VIN = 5V
VIN = 6.5V
60
50
40
30
0.1
1
10
LOAD CURRENT (mA)
1610 TA16
100
1610 TA17
RELATED PARTS
PART NUMBER
®
DESCRIPTION
COMMENTS
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Micropower Step-Down DC/DC Converter
94% Efficiency, 10µA IQ, 9V to 5V at 250mA
LT1307
Single Cell Micropower 600kHz PWM DC/DC Converter
3.3V at 75mA from 1 Cell, MSOP Package
LTC1440/1/2
Ultralow Power Single/Dual Comparators with Reference
2.8µA IQ, Adjustable Hysteresis
LTC1502-3.3
Single Cell to 3.3V Regulated Charge Pump
40µA IQ, No Inductors, 3.3V at 10mA from 1V Input
LT1521
Micropower Low Dropout Linear Regulator
500mV Dropout, 300mA Current, 12µA IQ
LT1611
Inverting 1.4MHz DC/DC Converter
5V to – 5V at 150mA, Tiny SOT-23 Package
LT1613
Step-Up 1.4MHz DC/DC Converter
3.3V to 5V at 200mA, Tiny SOT-23 Package
LTC1682
Doubler Charge Pump with Low Noise Linear Regulator
Fixed 3.3V and 5V Outputs, 1.8V to 4.4V Input Range, 50mA Output
16
Linear Technology Corporation
1610f LT/TP 0699 4K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 1998
工商网监
湘ICP备2023018690号
