LT1316CS8 [Linear]
Micropower DC/DC Converter with Programmable Peak Current Limit; 微功率DC / DC转换器，具有可编程峰值电流限制
| 型号： | LT1316CS8 |
| 厂家： | 
Linear |
| 描述： | Micropower DC/DC Converter with Programmable Peak Current Limit |
| 文件： | 总16页 (文件大小：347K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT1316
Micropower
DC/DC Converter
with Programmable
Peak Current Limit
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DESCRIPTION
FEATURES
The LT®1316 is a micropower step-up DC/DC converter
that operates from an input voltage as low as 1.5V. A
programmable input current limiting function allows pre-
cise control of peak switch current. Peak switch current
can be set to any value between 30mA and 500mA by
adjusting one resistor. This is particularly useful for
DC/DCconvertersoperatingfromhighsourceimpedance
inputs such as lithium coin cells or telephone lines.
■
Precise Control of Peak Switch Current
■
Quiescent Current:
33µA in Active Mode
3µA in Shutdown Mode
■
Low-Battery Detector Active in Shutdown
■
Low Switch VCESAT: 300mV at 500mA
■
8-Lead MSOP and SO Packages
■
Operates with VIN as Low as 1.5V
■
Logic Level Shutdown Pin
The fixed off-time, variable on-time regulation scheme
results in quiescent current of only 33µA in active mode.
Quiescent current decreases to 3µA in shutdown with the
low-battery detector still active.
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APPLICATIONS
■
Battery Backup
The LT1316 is available in 8-lead MSOP and SO packages.
■
LCD Bias
■
Low Power –48V to 5V/3.3V Converters
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATION
2-Cell to 5V Step-Up Converter
Efficiency vs Load Current
L1
47µH
D1
5V
50mA
90
80
70
60
3.3V
IN
R1
1M
1%
6
5
V
SW
IN
2.5V
1.8V
IN
8
1
7
2
SHDN
FB
+
IN
+
C2
47µF
C1
47µF
LT1316
2 CELLS
NC
LBI
LBO
GND
NC
R2
324k
1%
R
SET
3
4
R5
10k
1%
D1: MOTOROLA MBR0520L
L1: SUMIDA CD43-470
1316 TA01
0.1
1
10
100
LOAD CURRENT (mA)
1316 TA02
1
LT1316
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
VIN Voltage .............................................................. 12V
SW Voltage ............................................... –0.4V to 30V
FB Voltage ..................................................... VIN + 0.3V
RSET Voltage ............................................................. 5V
SHDN Voltage ............................................................ 6V
LBI Voltage ................................................................VIN
LBO Voltage............................................................. 12V
Maximum Switch Current ................................... 750mA
Maximum Junction Temperature ......................... 125°C
Operating Temperature Range
Commercial ............................................. 0°C to 70°C
Extended Commercial (Note 1).......... –40°C to 85°C
Industrial (Note 2) .............................. –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
TOP VIEW
NUMBER
LBO
LBI
1
2
3
4
8 FB
7 SHDN
R
GND
6 V
5 SW
LT1316CMS8
IN
SET
MS8 PACKAGE
8-LEAD PLASTIC MSOP
MS8 PART MARKING
LTCD
TJMAX = 125°C, θJA = 160°C/W
ORDER PART
NUMBER
TOP VIEW
LBO
LBI
1
2
3
4
FB
8
7
6
5
SHDN
LT1316CS8
LT1316IS8
R
V
SET
IN
GND
SW
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1316
1316I
TJMAX = 125°C, θJA = 120°C/W
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
Commercial grade 0°C to 70°C, Industrial grade –40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. (Notes 1, 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
1.65
12
UNITS
Minimum Operating Voltage
Maximum Operating Voltage
Quiescent Current
1.5
V
V
V
= 2V, Not Switching
33
45
50
µA
µA
SHDN
●
Quiescent Current in Shutdown
V
V
= 0V, V = 2V
●
●
3
7
5
10
µA
µA
SHDN
SHDN
IN
= 0V, V = 5V
IN
FB Pin Bias Current
Line Regulation
●
●
●
●
●
●
●
3
30
0.15
1.25
20
nA
%/V
V
V
= 1.8V to 12V
0.04
1.17
3
IN
LBI Input Threshold
LBI Pin Bias Current
LBI Input Hysteresis
LBO Output Voltage Low
LBO Output Leakage Current
Falling Edge
1.1
1.4
nA
mV
V
35
65
I
= 500µA
0.2
0.01
0.4
0.1
SINK
LBI = 1.7V, LBO = 5V
µA
SHDN Input Voltage High
SHDN Input Voltage Low
●
●
V
V
0.4
SHDN Pin Bias Current
V
V
= 5V
= 0V
●
●
2
–1
5
–3
µA
µA
SHDN
SHDN
2
LT1316
ELECTRICAL CHARACTERISTICS
Commercial grade 0°C to 70°C, Industrial grade –40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted. (Notes 1, 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Switch OFF Time
FB > 1V
1.4
1.1
2.0
2.6
3.0
µs
µs
●
FB < 1V
3.4
6.3
µs
Switch ON Time
Current Limit Not Asserted
1V < FB < 1.2V
4.4
3.4
8.2
9.5
µs
µs
●
●
Maximum Duty Cycle
Switch Saturation Voltage
Switch Leakage
Current Limit Not Asserted
1V < FB < 1.2V
74
73
76
90
90
%
%
I
I
= 0.5A
= 0.1A
●
●
0.30
0.06
0.4
0.15
V
V
SW
SW
Switch Off, V = 5V
●
0.1
5
µA
SW
Commercial grade 0°C to 70°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted.
FB Comparator Trip Point
●
1.21
1.23
1.25
V
Peak Switch Current
R
SET
R
SET
R
SET
= 27.4k, T = 25°C
90
90
70
100
100
90
110
115
110
mA
mA
mA
A
= 27.4k, T =0°C
A
= 27.4k, T = 70°C
A
R
R
= 10K
●
●
250
290
25
340
mA
mA
SET
SET
= 121k
Industrial grade –40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted.
FB Comparator Trip Point
1.205
1.23
1.255
V
Peak Switch Current
R
SET
R
SET
= 27.4k,
= 10k
●
●
70
200
100
290
125
370
mA
mA
The ● denotes specifications which apply over the specified temperature
over the –40°C to 85°C temperature range by design or correlation, but
range.
are not production tested.
Note 1: C grade device specifications are guaranteed over the 0°C to 70°C
temperature range. In addition, C grade device specifications are assured
Note 2: I grade device specifications are guaranteed over the –40°C to
85°C temperature range.
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TYPICAL PERFORMANCE CHARACTERISTICS
Load Transient Response
Burst ModeTM Operation
VOUT
100mV/DIV
AC COUPLED
VOUT
100mV/DIV
AC COUPLED
VSW
5V/DIV
50mA
ILOAD
INDUCTOR
CURRENT
200mA/DIV
0mA
1316 G01
1316 G02
Burst Mode IS A TRADEMARK OF LINEAR TECHNOLOGY
CORPORATION.
3
LT1316
TYPICAL PERFORMANCE CHARACTERISTICS
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Switch Saturation Voltage
vs Switch Current
LBI Pin Bias Current
vs Temperature
Off-Time vs Temperature
500
400
300
200
100
0
8
6
4
2
0
4
3
2
1
0
75°C
100°C
–40°C
25°C
–50 –25
0
25
50
75
100
400
0
100 200 300
500 600 700 800
–50 –25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
SWITCH CURRENT (mA)
1316 G04
1316 G03
1316 G05
Maximum On-Time
vs Temperature
Quiescent Current vs Temperature
Feedback Voltage vs Temperature
1.240
1.235
1.230
1.225
1.220
8
7
6
5
36
34
32
30
28
26
–50 –25
0
25
50
75
100
–50 –25
0
25
50
75
100
–50 –25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1316 G08
1316 G06
1316 G07
FB Pin Bias Current
vs Temperature
Shutdown Pin Bias Current
vs Shutdown Pin Voltage
Peak Switch Current
vs Temperature
1000
100
10
4
3
2
1
4
3
R
SET
= 4.84k
R
SET
= 10k
2
R
= 27.4k
= 97.3k
SET
1
R
SET
0
–1
–50 –25
0
25
50
75
100
0
1
2
3
4
5
6
–50 –25
0
25
50
75
100
TEMPERATURE (°C)
SHUTDOWN PIN VOLTAGE (V)
TEMPERATURE (°C)
1316 G11
1316 G09
1316 G10
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LT1316
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PIN FUNCTIONS
SW (Pin 5): Collector of NPN Power Transistor. Keep
LBO (Pin 1): Low-Battery Detector Output. Open collector
cansinkupto500µA. Low-batterydetectorremainsactive
in shutdown mode.
traces at this pin as short as possible.
VIN (Pin 6): Input Supply. Must be bypassed close to the
pin.
LBI (Pin 2): Low-Battery Detector Input. When voltage at
this pin drops below 1.17V, LBO goes low.
SHDN(Pin7):Shutdown. Groundthispintoplacethepart
in shutdown mode (only the low-battery detector remains
active). Tie to a voltage between 1.4V and 6V to enable the
device. SHDN pin is logic level and need only meet the
logic specification (1.4V for high, 0.4V for low).
R
SET (Pin 3): A resistor between RSET and GND programs
peak switch current. The resistor value should be between
3k and 150k. Do not float or short to ground. This is a high
impedance node. Keep traces at this pin as short as
possible. Do not put capacitance at this pin.
FB (Pin 8): 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).
GND (Pin 4): Ground. Connect directly to ground plane.
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BLOCK DIAGRA
D1
L1
V
V
OUT
IN
C1
R1
LB0
1
V
IN
SW
6
5
2
LBI
+
1.5V
UNDERVOLTAGE
LOCKOUT
A3
–
R3 = 10R4
R4
–
+
FB
8
1.17V
–
R2
+
A1
A2
V
REF
1.23V
OSCILLATOR
6.3µs ON
2µs OFF
0.5V
+
DRIVER
A4
Q2
×1
–
Q1
×200
3
4
7
SHDN
1316 F01
R
GND
SET
R5
Figure 1. LT1316 Block Diagram
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LT1316
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APPLICATIONS INFORMATION
During the portion of the switch cycle when Q1 is turned
off, current is forced through D1 to C1 causing output
voltage to rise. This switching action continues until
output voltage rises enough to overcome A1’s hysteresis.
Table 1 simplifies component selection for commonly
used input and output voltages. The methods used in
determiningthesevaluesarediscussedinmoredetaillater
in this data sheet.
Peak switch current is set by a resistor from the RSET pin
to ground. Voltage at the RSET pin is forced to 0.5V by A4
and is used to set up a constant current through R5. This
currentalsoflowsthroughR3whichsetsthevoltageatthe
positive input of comparator A2. When Q1 turns on, the
SW pin goes low and current ramps up at the rate VIN/L.
CurrentthroughQ2isequaltoQ1’scurrentdividedby200.
When current through Q2 causes the voltage drop across
R4 and R3 to be equal, A2 changes state and resets the
oscillator, causing Q1 to turn off. Shutdown is accom-
plished by grounding the SHDN pin.
V
OUT can be set using the equation:
V
OUT
R1
R2 + R1
FB
V
= 1.23
OUT
)
)
R2
R2
1316 EQF01
Table 1. RSET Resistor and Inductor Values
LOAD
CURRENT RESISTOR INDUCTOR
R
PEAK SWITCH
CURRENT
SET
V
IN
V
OUT
2
5
10mA
25mA
50mA
75mA
100mA
1mA
36.8k
18.2k
10k
100µH
68µH
80mA
165mA
320mA
500mA
490mA
56mA
The low-battery detector A3 has its own 1.17V reference
andisalwayson.Theopencollectoroutputdevicecansink
up to 500µA. Approximately 35mV of hysteresis is built
into A3 to reduce “buzzing” as the battery voltage reaches
the trip level.
2
2
2
5
5
5
5
5
5
5
47µH
6.81k
6.81k
75k
33µH
12
28
28
28
82µH
100µH
100µH
100µH
5mA
22.1k
10k
140mA
270mA
Current Limit
10mA
During active mode when the part is switching, current in
the inductor ramps up each switch cycle until reaching a
preprogrammed current limit. This current limit value
must be set by placing the appropriate resistor from the
RSET pin to ground. This resistance value can be found by
using Figure 3 to locate the desired DC current limit and
Operation
To understand operation of the LT1316, first examine
Figure 1. Comparator A1 monitors FB voltage which is
VOUT divided down by resistor divider network R1/R2.
When voltage at the FB pin drops below the reference
voltage (1.23V), A1’s output goes high and the oscillator
is enabled. The oscillator has an off-time fixed at 2µs and
an on-time limited to 6.3µs. Power transistor Q1 is cycled
on and off by the oscillator forcing current through the
inductor to alternately ramp up and down (see Figure 2).
1000
100
10
VOUT
AC COUPLED
200mV/DIV
VSW
5V/DIV
INDUCTOR
CURRENT
100mA/DIV
10
100
R
(kΩ)
SET
1316 F03
1316 F02
Figure 3. DC Current Limit vs RSET Resistor
Note: DC Current is the Peak Switch Current if the Power
Transistor had Zero Turn-Off Delay
10µs/DIV
Figure 2. Switching Waveforms
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LT1316
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APPLICATIONS INFORMATION
then adding in the amount of overshoot that will occur due
to turn-off delay of the power transistor. This turn-off
delay is approximately 300ns.
V
– V + V
OUT IN D
L =
(t
)
OFF
(2)
0.4(I
)
PEAK
where tOFF = 2µs and VD = 0.4V.
Peak switch current = DC current limit from graph +
VIN/L(turn-off delay)
As a result of equations 1 and 2, ripple current during
switching will be 40% of the peak current (see Figure 2).
Using these equations at the specified IOUT, the part is
delivering approximately 60% of its maximum output
power. In other words, the part is operating on a 40%
reserve. This is a safe margin to use and can be decreased
if input voltage and output current are tightly controlled.
Example:
Set peak switch current to 100mA for: VIN = 2V,
L = 33µH
Overshoot = VIN/L(turn-off delay) = (2/33µH)(300ns)
= 18.2mA
For some applications, this recommended inductor size
may be too large. Inductance can be reduced but available
output power will decrease. Also, ripple current during
switching will increase and may cause discontinuous
operation. Discontinuous operation occurs when
inductor current ramps down to zero at the end of each
switch cycle (see Figure 4). Shown in Figure 5 is minimum
inductance vs peak current for the part to remain in
continuous mode.
Refer to RSET graph and locate
(100mA – 18.2mA) ≈ 82mA
RSET ≈ 33k
Calculating Duty Cycle
For a boost converter running in continuous conduction
mode,dutycycleisconstrainedbyVIN andVOUT according
to the equation:
V
– V + V
IN D
0mA
INDUCTOR
CURRENT
100mA/DIV
OUT
DC =
V
– V
+ V
OUT
SAT D
where VD = diode voltage drop ≈ 0.4V and VSAT = switch
saturation voltage ≈ 0.2V.
SW PIN
5V/DIV
If the duty cycle exceeds the LT1316’s minimum specified
duty cycle of 0.73, the converter cannot operate in con-
tinuous conduction mode and must be designed for
discontinuous mode operation.
1316 F04
2µs/DIV
Figure 4. Discontinuous Mode Operation
1000
Inductor Selection and Peak Current Limit for
Continuous Conduction Mode
5V TO 18V
5V TO 12V
Peak current and inductance determine available output
power. Both must be chosen properly. If peak current or
inductance is increased, output power increases. Once
output power or current and duty cycle are known, peak
current can be set by the following equation, assuming
continuous mode operation:
2V TO 5V
100
10
10
2(I
1 – DC
)
100
1000
OUT
I
=
(1)
PEAK CURRENT (mA)
PEAK
1316 F05
Figure 5. Minimum Inductance vs Peak Current
for Continuous Mode Operation
Inductance can now be calculated using the peak current:
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LT1316
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APPLICATIONS INFORMATION
Discontinuous Mode Operation
2(I
1 – DC
)
2(10mA)
1 – 0.654
OUT
I
=
=
= 58mA
2.
PEAK
A boost converter with a high VOUT:VIN ratio operates with
a high duty cycle in continuous mode. For duty cycles
exceeding the LT1316’s guaranteed minimum specifica-
tion of 0.73, the circuit will need to be designed for
discontinuous operation. Additionally, very low peak cur-
rentlimitingbelow50mAmaynecessitateoperatinginthis
modeunlesshighinductancevaluesareacceptable.When
operating in discontinuous mode, a different equation
governsavailableoutputpower. Foreachswitchcycle, the
inductor current ramps down to zero, completely releas-
ing the stored energy. Energy stored in the inductor at any
time is equal to 1/2 LI2. Because this energy is released
each cycle, the equation for maximum power out is:
3. Find L
V
– V + V
IN D
OUT
0.4(I
L =
t
OFF
)
)
)
PEAK
5 – 2 + 0.4
0.4(58mA)
= 293µH
=
2µs
)
)
4. Find RSET resistor
V
L
IN
Overshoot =
=
300ns
)
)
2
P
= 1/2L(I
)f
OUT(MAX)
PEAK
2
= 1.8mA
)
)
1
330µH
I
(L)
Where f =
PEAK
+ t
)
)
OFF
Find RSET from Figure 3 for 58mA – 1.8mA = 56.2mA
V – V
IN
SAT
R
SET ≈ 47k
When designing for very low peak currents (<50mA), the
inductor size needs to be large enough so that on-time is
a least 1µs. On-time can be calculated by the equation:
Design Example 2
Requirements: VIN = 3.3V, VOUT = 28V and ILOAD = 5mA.
1. Find duty cycle:
I
• L
PEAK
On-Time =
)
)
(V – V
)
IN
SAT
V
– V + V
IN D
– V + V
28 – 3.3 + 0.4
OUT
OUT
DC =
= 0.89
=
)
)
)
V
)
28 – 0.2 + 0.4
SAT D
where VSAT = 0.2V.
Because duty cycle exceeds LT1316 minimum specifi-
cation of 73%, the circuit must be designed for discon-
tinuous operation.
Also, at these low current levels, current overshoot due to
powertransistorturn-offdelay willbeasignificantportion
of peak current. Increasing inductor size will keep this to
a minimum.
2. Find POUT(MAX)
Multiply POUT by 1.4 to give a safe operating margin
POUT(MAX) = POUT(1.4) = (5mA)(28V)(1.4) = 0.196W
Design Example 1
Requirements: VIN = 2V, VOUT = 5V and ILOAD = 10mA.
1. Find duty cycle
3. Set the on-time to the data sheet minimum of 3.4µs and
find L
V
V
– V + V
IN D
5 – 2 + 0.4
OUT
OUT
2
2
DC =
= 0.654
=
(t )(V – V )
SAT
)
)
)
)
ON
IN
5 – 0.2 + 0.4
– V + V
L =
=
SAT D
2P
(t + t
)
OUT(MAX) ON OFF
Because duty cycle is less than the LT1316 minimum
specification (0.73), the circuit can be designed for
continuous operation.
2
2
(3.4µs )(3.3 – 0.2)
2(0.196W)(3.4µs + 2µs)
= 52µH
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LT1316
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APPLICATIONS INFORMATION
4. Find IPEAK for 3.4µs on-time
For through-hole applications Sanyo OS-CON capacitors
offer extremely low ESR in a small package size. If peak
switch current is reduced using the RSET pin, capacitor
requirements can be eased and smaller, higher ESR units
can be used. Ordinary generic capacitors can generally be
used when peak switch current is less than 100mA,
although output voltage ripple may increase.
t (V – V
)
3.4µs(3.3 – 0.2)
52µH
ON IN
SAT
I
=
=
PEAK
L
= 0.202A
5. Find RSET resistor
V
L
IN
Diodes
Overshoot =
=
300ns
)
)
)
Most of the application circuits on this data sheet specify
the Motorola MBR0520L surface mount Schottky diode.
This 0.5A, low drop diode suits the LT1316 well. In lower
current applications, a 1N4148 can be used although
efficiency will suffer due to the higher forward drop. This
effect is particularly noticeable at low output voltages. For
higher output voltage applications, such as LCD bias
generators, the extra drop is a small percentage of the
output voltage so the efficiency penalty is small. The low
cost of the 1N4148 makes it attractive wherever it can be
used. In through-hole applications the 1N5818 is the all
around best choice.
3.3
52µH
300ns = 19mA
)
Find RSET from Figure 3 for 0.202A – 19mA = 0.183A
RSET ≈ 13k
These discontinuous mode equations are designed to
minimize peak current at the expense of inductor size. If
smaller inductors are desired peak current must be
increased.
Capacitor Selection
Lowering Output Ripple Voltage
LowESR(EquivalentSeriesResistance)capacitorsshould
be used at the output of the LT1316 to minimize output
ripple voltage. High quality input bypassing is also
required. For surface mount applications AVX TPS series
tantalum capacitors are recommended. These have been
specifically designed for switch mode power supplies and
have low ESR along with high surge current ratings.
Toobtainloweroutputripplevoltage,asmallfeedforward
capacitor of about 50pF to 100pF may be placed from
VOUT to FB as detailed in Figure 6. Ripple voltages with
and without the added capacitor are pictured in Figures
7 and 8.
L1
47µH
SHUTDOWN
D1
V
OUT
R1
1M
1%
+
C1
100pF
47µF
V
SW
IN
SHDN
FB
+
R2
324k
1%
2
LT1316
47µF
CELLS
R
SET
GND
10k
1316 F06
Figure 6. 2-Cell to 5V Step-Up Converter
with Reduced Output Ripple Voltage
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LT1316
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APPLICATIONS INFORMATION
VOUT
100mV/DIV
AC COUPLED
VOUT
100mV/DIV
AC COUPLED
IL
IL
100mA/DIV
100mA/DIV
1316 F07
1316 F08
100µs/DIV
50µs/DIV
Figure 7. Switching Waveforms for the Circuit
Shown in Figure 7 Without C1. The Output Ripple
Voltage is Approximately 140mVP-P
Figure 8. By Adding C1, Output Ripple Voltage
is Reduced to Less Than 80mVP-P
Layout/Input Bypassing
1µF ceramic capacitor acts to smooth voltage spikes at
switchturn-onandturn-off.Ifthepowersourceisfaraway
from the IC, inductance in the power source leads results
in high impedance at high frequency. A local high capaci-
tance bypass is then required to restore low impedance at
the IC.
The LT1316’s high speed switching mandates careful
attentiontoPCboardlayout.Suggestedcomponentplace-
mentisshowninFigure9. Theinputsupplymusthavelow
impedance at AC and the input capacitor should be placed
as indicated in the figure. The value of this capacitor
depends on how close the input supply is to the IC. In
situations where the input supply is more than a few
inches away from the IC, a 47µF to 100µF solid tantalum
bypass capacitor is required. If the input supply is close to
the IC, a 1µF ceramic capacitor can be used instead. The
LT1316 switches current in pulses up to 0.5A, so a low
impedance supply must be available. If the power source
(for example, a 2 AA cell battery) is within 1 or 2 inches of
the IC, the battery itself provides bulk capacitance and the
Low-Battery Detector
TheLT1316containsanindependentlow-batterydetector
that remains active when the device is shut down. This
detector, actually a hysteretic comparator, has an open
collector output that can sink up to 500µA. The compara-
tor also operates below the switcher’s undervoltage lock-
out threshold, operating until VIN reaches approximately
1.4V.
1
8
7
2
3
4
LT1316
V
6
5
IN
L
R
SET
C
IN
GND
D
C
OUT
+
1316 F09
V
OUT
Figure 9. Suggested PC Layout
10
LT1316
U
TYPICAL APPLICATIONS N
Nonisolated –48V to 5V Flyback Converter
V
OUT
D1
1N5817
5V
T1
10:1:1
50mA
2
L3
1
3
L1
4
+
C3
47µF
D2
1N4148
7
L2
6
D3
1N4148
C2
0.022µF
R1
1.3M
V
A
Q1
5
+
C4
47µF
R4
2M
6
V
SW
IN
7
1
2
C1
SHDN
LB0
0.1µF
R7
T1
=
DALE LPE-4841-A313 (605-665-9301)
L: 2mH
Q2
MPSA92
432k, 1%
PRI
8
R2
1.30M
1%
LT1316
FB
R
: 4.3Ω AT V = 2.5V
DS(ON)
GS
R6, Q2,R7 MUST BE PLACED NEXT
TO THE FB PIN
Q3
2N3904
R6
121k
1%
LBI
I
= 190µA WHEN
= 48V, I
IN
IN
R
GND
4
SET
3
V
= 1mA
LOAD
R3
604k
1%
R5
69.8k
1%
1316 • TA03
– 48V
Efficiency vs Load Current
90
80
36V
IN
70
60
50
40
48V
IN
72V
IN
1
10
LOAD CURRENT (mA)
100
1316 TA04
11
LT1316
TYPICAL APPLICATIONS N
U
Positive-to-Negative Converter for LCD Bias
D1
MMBD914
L1
33µH
SHUTDOWN
V
IN
C2
C3
R1
0.01µF
50V
100pF
50V
6
5
SW
3.3M
V
IN
2.2M
8
7
CONTRAST
ADJUST
SHDN
FB
+
C1
33µF
10V
R2
210k
LT1316
2 CELLS
+
C4
1µF
35V
R
GND
4
SET
3
C6
0.33µF
50V
C5
2.2µF
35V
+
D2
MMBD914
R3
15k
V
–20V
6mA
OUT
D3
C4: SPRAGUE 293D105X9035B2T
C5: SPRAGUE 293D225X0035B2T
L1: SUMIDA CD43-330
MBR0530L
1316 TA06
Battery-Powered Solenoid Driver
L1
47µH
V
CAP
BAT-85
ZTX949
V
IN
47k
1N4148
6
5
SW
470k
6.8M
5k
V
IN
1
7
2
LBO
LBI
+
C2
+
C1
1.3k
470µF
50V
LT1316
47µF
2 CELLS
SOLENOID
16V
8
SHDN
FB
R
GND
SET
50k
324K
V
4
2N3904
3
ENERGIZE
20k
1316 TA08
C1: AVX TPS 47µF, 16V
C2: SANYO 50MV470GX
L1: SUMIDA CD43-470
CAP
GOOD
SHUTDOWN
When Solenoid Is Energized (VENERGIZE High) Peak Input Current
Remains Low and Controlled, Maximizing Battery Life
VENERGIZE
5V/DIV
IL1
200mA/DIV
VCAP
10V/DIV
CAP GOOD
5V/DIV
1316 TA09
500ms/DIV
12
LT1316
U
TYPICAL APPLICATIONS N
Super Cap Backup Supply
R1
10k
READY
1M
D1
0.5A
L1
47µH
CONNECT TO
MAIN SUPPLY
5V
6
5
SW
6mA
V
IN
1
2
7
1.00M
357k
LBO
LBI
C
SUP
+
C
+
+
OUT
C
IN
0.1F
5.5V
75Ω
100pF
LT1316
SET
1.00M
324k
33µF
33µF
10V
8
10V
SHDN
FB
R
SET
3
GND
4
R
33k
RUN
1316 TA10
MBR0520LT3
SUMIDA CD43-470
D1:
L1:
C
, C : TAJB330M010R
SUP
IN OUT
C
: PANASONIC EEC-S5R5V104
50V to 6V Isolated Flyback Converter
T1
PRI
10:1:1
L
: 2mH
1N5817
+V
IN
+
25V TO
50V
3
2
V
C1
100µF
16V
OUT
+
6V/20mA
75% EFFICIENCY
4
1
–
7
1N4148
510k
2M
0.022µF
100V
CERAMIC
Q1
5
6
1N4148
6
V
SW
IN
7
1
2
0.1µF
SHDN
LB0
50k
1µF
8
LT1316
FB
1.30M
1%
16V
CERAMIC
2N3904
12.7k
LBI
R
GND
4
SET
3
604k
1%
C1 = SANYO OS-CON 100µF, 16V
Q1 = ZETEX ZVN 4424A
T1
= DALE LPE-4841-A313 (605-665-9301)
69.8k
1%
1316 TA11
13
LT1316
TYPICAL APPLICATIONS N
U
LCD Bias Generator with Output Disconnect in Shutdown
V
BAT
1.6V TO 3.5V
150k
OPTIONAL CONNECTION
L1
22µH
MBR0540LT1
V
OUT
V
IN
17.1V TO 19.8V
4mA
3.3V
Q1
100pF
50V
CERAMIC
6
5
SW
3.32M
1%
V
IN
+
C1
22µF
6.3V
8
FB
LT1316
7
SHDN
SHUTDOWN
0.33µF
50V
CERAMIC
+
C2
232k
1%
4.7M
3.3µF
R
GND
4
SET
35V
3
11k
1%
1316 TA12
V
OUT
0V TO 3.3V
ADJ
C1: AVX TAJA226M006R
C2: AVX TAJB335M035R
L1: MURATA LQH3C220K04
Q1: MMBT3906LT3
(V
ADJUST)
Universal Serial Bus (USB) to 5V/100mA DC/DC Converter
R
B
100Ω
L1
33µH
D1
V
V
IN
OUT
4V TO
7V
5V
100mA
Q1
6
5
V
SW
IN
7
3
+
C2
33µF
10V
+
C3
SHDN
R2
1.00M
+
100pF
10µF
C1
10µF
10V
10V
LT1316
8
R
SET
FB
GND
4
R1
324k
R3
10k
1316 TA13
C1: 10µF 10V AVX TAJB106M010
C2: 33µF 10V AVX TPSC336M010
C3: 10µF ALUMINUM ELECTROLYTIC
D1: MBR0520LT1
L1: 33µH SUMIDA CD43 (OR COILCRAFT DO1608)
Q1: MPS1907A
14
LT1316
U
PACKAGE DESCRIPTION Dimensions in inches (millimeter) 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
2
3
4
0.040 ± 0.006
(1.02 ± 0.15)
0.034 ± 0.004
(0.86 ± 0.102)
0.007
(0.18)
0° – 6° TYP
SEATING
PLANE
0.012
(0.30)
REF
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
0.0256
(0.65)
TYP
*
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
MSOP (MS8) 1197
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
5
8
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
3
4
2
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
0.050
(1.270)
TYP
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
SO8 0996
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
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 represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
15
LT1316
TYPICAL APPLICATIONS N
U
Low Profile 2 Cell-to-28V Converter for LCD Bias
L1
22µH
D1
V
V
OUT
IN
28V
5mA
6
5
SW
C4
100pF
50V
C3
V
0.33µF
IN
7
1
2
50V
4.32M
204k
SHUTDOWN
SHDN
LBI
+
C2
1µF
35V
8
C1
10µF
LT1316
FB
2 CELLS
LBO
R
GND
4
SET
3
10k
1316 TA05
C1: MURATA GRM235Y5V106Z010
C2: SPRAGUE 293D105X9035B2T
C3: 0.33µF CERAMIC, 50V
C4: 100pF CERAMIC, 50V
D1: BAT-54
L1: MURATA LQH3C220K04
Bipolar LCD Bias Supply
L1
47µH
1N914
V
IN
2N3904
13V
0.5mA
3.3V TO
4.2V
C2
1µF
35V
+
22k
10k
6
5
V
SW
IN
100pF
1.00M
7
8
SHDN LT1316
FB
+
C1
22µF
16V
+
C3
1µF
35V
88.7k
+
C4
R
GND
4
SET
3
3.3µF
35V
–15V
1.5mA
(BAT54 = TWO DIODES IN SOT23)
47k
BAT54
× 2
1316 TA14
C1: AVX TAJB226M016R
C2, C3: AVX TAJA105K035R
C4: AVX TAJB335M035R
L1: MURATA LQH3C470
RELATED PARTS
PART NUMBER
LTC®1163
LTC1174
LT1302
DESCRIPTION
COMMENTS
1.8V Minimum Input, Drives N-Channel MOSFETs
Triple High Side Driver for 2-Cell Inputs
Micropower Step-Down DC/DC Converter
94% Efficiency, 130µA I , 9V to 5V at 300mA
Q
High Output Current Micropower DC/DC Converter
2-Cell Micropower DC/DC Converter
5V/600mA from 2V, 2A Internal Switch, 200µA I
Q
LT1304
Low-Battery Detector Active in Shutdown, 5V at 200mA for 2 Cells
LT1307
Single Cell Micropower 600kHz PWM DC/DC Converter 3.3V at 75mA from 1 Cell
Ultralow Power Single/Dual Comparators with Reference 2.8µA I , Adjustable Hysteresis
LTC1440/1/2
LTC1516
LT1521
Q
2-Cell to 5V Regulated Charge Pump
12µA I , No Inductors, 5V at 50mA from 3V Input
Q
Micropower Low Dropout Linear Regulator
500mV Dropout, 300mA Current, 12µA I
Q
1316f LT/TP 0298 4K • PRINTED IN USA
Linear Technology Corporation
●
1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900
16
●
●
FAX: (408) 434-0507 TELEX: 499-3977 www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 1997
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