LINER LT1316IS8

LT1316
Micropower
DC/DC Converter
with Programmable
Peak Current Limit
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DESCRIPTION
FEATURES
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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 precise 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/DC converters operating from high source impedance
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
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Battery Backup
LCD Bias
Low Power – 48V to 5V/3.3V Converters
The LT1316 is available in 8-lead MSOP and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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TYPICAL APPLICATION
2-Cell to 5V Step-Up Converter
L1
47µH
7
+
2 CELLS
C1
47µF
D1
5
SW
VIN
SHDN
FB
5V
50mA
R1
1M
1%
8
2
LBI
RSET
3
R5
10k
1%
D1: MOTOROLA MBR0520L
L1: SUMIDA CD43-470
LBO
+
GND
4
1
3.3VIN
2.5VIN
LT1316
NC
90
C2
47µF
NC
R2
324k
1%
EFFICIENCY (%)
6
Efficiency vs Load Current
1.8VIN
80
70
60
1316 TA01
0.1
1
10
100
LOAD CURRENT (mA)
1316 TA02
1
LT1316
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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
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
LBO
LBI
RSET
GND
8
7
6
5
1
2
3
4
FB
SHDN
VIN
SW
LT1316CMS8
MS8 PACKAGE
8-LEAD PLASTIC MSOP
MS8 PART MARKING
TJMAX = 125°C, θJA = 160°C/W
LTCD
ORDER PART
NUMBER
TOP VIEW
LBO 1
8
FB
LBI 2
7
SHDN
RSET 3
6
VIN
GND 4
5
SW
LT1316CS8
LT1316IS8
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
Minimum Operating Voltage
TYP
MAX
UNITS
1.5
1.65
V
Maximum Operating Voltage
Quiescent Current
12
V
33
45
50
µA
µA
●
●
3
7
5
10
µA
µA
●
3
30
nA
VSHDN = 2V, Not Switching
●
Quiescent Current in Shutdown
VSHDN = 0V, VIN = 2V
VSHDN = 0V, VIN = 5V
FB Pin Bias Current
Line Regulation
VIN = 1.8V to 12V
●
LBI Input Threshold
Falling Edge
●
LBI Pin Bias Current
1.1
●
LBI Input Hysteresis
0.04
0.15
%/V
1.17
1.25
V
3
20
nA
●
35
65
mV
LBO Output Voltage Low
ISINK = 500µA
●
0.2
0.4
V
LBO Output Leakage Current
LBI = 1.7V, LBO = 5V
●
0.01
0.1
µA
0.4
V
V
5
–3
µA
µA
SHDN Input Voltage High
SHDN Input Voltage Low
SHDN Pin Bias Current
2
●
●
VSHDN = 5V
VSHDN = 0V
●
●
1.4
2
–1
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
Switch OFF Time
FB > 1V
●
MIN
TYP
MAX
UNITS
1.4
1.1
2.0
2.6
3.0
µs
µs
FB < 1V
µs
3.4
Current Limit Not Asserted
1V < FB < 1.2V
4.4
3.4
6.3
●
8.2
9.5
µs
µs
Current Limit Not Asserted
1V < FB < 1.2V
74
73
76
●
90
90
%
%
Switch Saturation Voltage
ISW = 0.5A
ISW = 0.1A
●
●
0.30
0.06
0.4
0.15
V
V
Switch Leakage
Switch Off, VSW = 5V
●
0.1
5
µA
1.21
1.23
1.25
V
90
90
70
100
100
90
110
115
110
mA
mA
mA
●
250
290
25
340
mA
mA
●
1.205
1.23
1.255
●
●
70
200
100
290
125
370
Switch ON Time
Maximum Duty Cycle
Commercial grade 0°C to 70°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted.
FB Comparator Trip Point
●
Peak Switch Current
RSET = 27.4k, TA = 25°C
RSET = 27.4k, TA =0°C
RSET = 27.4k, TA = 70°C
RSET = 10K
RSET = 121k
Industrial grade – 40°C to 85°C, VIN = 2V, VSHDN = VIN, TA = 25°C unless otherwise noted.
FB Comparator Trip Point
Peak Switch Current
RSET = 27.4k,
RSET = 10k
The ● denotes specifications which apply over the specified temperature
range.
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
V
mA
mA
over the – 40°C to 85°C temperature range by design or correlation, but
are not production tested.
Note 2: I grade device specifications are guaranteed over the – 40°C to
85°C temperature range.
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TYPICAL PERFORMANCE CHARACTERISTICS
Burst ModeTM Operation
Load Transient Response
VOUT
100mV/DIV
AC COUPLED
VOUT
100mV/DIV
AC COUPLED
50mA
VSW
5V/DIV
ILOAD
INDUCTOR
CURRENT
200mA/DIV
0mA
1316 G01
1316 G02
Burst Mode IS A TRADEMARK OF LINEAR TECHNOLOGY
CORPORATION.
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LT1316
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TYPICAL PERFORMANCE CHARACTERISTICS
Switch Saturation Voltage
vs Switch Current
LBI Pin Bias Current
vs Temperature
Off-Time vs Temperature
8
4
6
3
75°C
100°C
300
–40°C
200
25°C
100
0
0
OFF-TIME (µs)
400
LBI PIN CURRENT (nA)
SWITCH SATURATION VOLTAGE (mV)
500
4
2
1
0
–50
100 200 300 400 500 600 700 800
SWITCH CURRENT (mA)
–25
0
25
50
TEMPERATURE (°C)
75
Maximum On-Time
vs Temperature
–25
0
25
50
TEMPERATURE (°C)
75
34
32
30
28
26
–50
100
–25
0
25
50
TEMPERATURE (°C)
75
1316 G06
75
100
1316 G11
–25
0
25
50
TEMPERATURE (°C)
75
100
1316 G08
RSET = 4.84k
PEAK SWITCH CURRENT (mA)
FB PIN BIAS CURRENT (nA)
SHUTDOWN PIN CURRENT (µA)
0
25
50
TEMPERATURE (°C)
1.220
–50
1000
3
2
1
0
–1
–25
1.225
Peak Switch Current
vs Temperature
4
2
1
–50
100
1.230
Shutdown Pin Bias Current
vs Shutdown Pin Voltage
4
100
1.235
1316 G07
FB Pin Bias Current
vs Temperature
3
75
Feedback Voltage vs Temperature
FEEDBACK VOLTAGE (V)
QUIESCENT CURRENT (µA)
MAXIMUM ON-TIME (µs)
6
0
25
50
TEMPERATURE (°C)
1.240
36
7
–25
1316 G05
Quiescent Current vs Temperature
8
4
0
–50
100
1316 G04
1316 G03
5
–50
2
0
1
2
3
4
5
SHUTDOWN PIN VOLTAGE (V)
6
1316 G09
RSET = 10k
RSET = 27.4k
100
RSET = 97.3k
10
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
1316 G10
LT1316
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PIN FUNCTIONS
SW (Pin 5): Collector of NPN Power Transistor. Keep
traces at this pin as short as possible.
LBO (Pin 1): Low-Battery Detector Output. Open collector
can sink up to 500µA. Low-battery detector remains active
in shutdown mode.
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 (Pin 7): Shutdown. Ground this pin to place the part
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).
RSET (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
VOUT
VIN
C1
LB0
6
1
+
A3
–
5
SW
1.5V
UNDERVOLTAGE
LOCKOUT
R4
R3 = 10R4
–
1.17V
–
+
8
FB
R2
A1
+
LBI 2
VIN
R1
A2
VREF
1.23V
0.5V
+
DRIVER
A4
Q2
×1
–
3
Q1
×200
7
4
RSET
OSCILLATOR
6.3µs ON
2µs OFF
GND
1316 F01
SHDN
R5
Figure 1. LT1316 Block Diagram
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LT1316
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APPLICATIONS INFORMATION
Table 1 simplifies component selection for commonly
used input and output voltages. The methods used in
determining these values are discussed in more detail later
in this data sheet.
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.
VOUT can be set using the equation:
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
current also flows through R3 which sets the voltage at the
positive input of comparator A2. When Q1 turns on, the
SW pin goes low and current ramps up at the rate VIN/L.
Current through Q2 is equal to Q1’s current divided by 200.
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 accomplished by grounding the SHDN pin.
)
)
R2 + R1
VOUT = 1.23
R2
R1
FB
R2
1316 EQF01
Table 1. RSET Resistor and Inductor Values
VIN
VOUT
LOAD
CURRENT
RSET
RESISTOR
INDUCTOR
PEAK SWITCH
CURRENT
2
5
10mA
36.8k
100µH
80mA
2
5
25mA
18.2k
68µH
165mA
2
5
50mA
10k
47µH
320mA
2
5
75mA
6.81k
33µH
500mA
5
12
100mA
6.81k
82µH
490mA
5
28
1mA
75k
100µH
56mA
5
28
5mA
22.1k
100µH
140mA
5
28
10mA
10k
100µH
270mA
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).
VOUT
AC COUPLED
200mV/DIV
The low-battery detector A3 has its own 1.17V reference
and is always on. The open collector output device can sink
up to 500µA. Approximately 35mV of hysteresis is built
into A3 to reduce “buzzing” as the battery voltage reaches
the trip level.
Current Limit
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
1000
DC CURRENT LIMIT (mA)
VOUT
100
VSW
5V/DIV
10
INDUCTOR
CURRENT
100mA/DIV
10
100
RSET (kΩ)
1316 F03
10µs/DIV
Figure 2. Switching Waveforms
6
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
LT1316
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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.
Peak switch current = DC current limit from graph +
VIN/L(turn-off delay)
Example:
Set peak switch current to 100mA for: VIN = 2V,
L = 33µH
Overshoot = VIN/L(turn-off delay) = (2/33µH)(300ns)
= 18.2mA
Refer to RSET graph and locate
(100mA – 18.2mA) ≈ 82mA
RSET ≈ 33k
Calculating Duty Cycle
For a boost converter running in continuous conduction
mode, duty cycle is constrained by VIN and VOUT according
to the equation:
VOUT – VIN + VD
VOUT – VSAT + VD
If the duty cycle exceeds the LT1316’s minimum specified
duty cycle of 0.73, the converter cannot operate in continuous conduction mode and must be designed for
discontinuous mode operation.
where tOFF = 2µs and VD = 0.4V.
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.
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.
SW PIN
5V/DIV
2µs/DIV
1316 F04
Figure 4. Discontinuous Mode Operation
1000
Inductor Selection and Peak Current Limit for
Continuous Conduction Mode
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:
2(IOUT)
1 – DC
(2)
0mA
INDUCTOR
CURRENT
100mA/DIV
where VD = diode voltage drop ≈ 0.4V and VSAT = switch
saturation voltage ≈ 0.2V.
IPEAK =
VOUT – VIN + VD
(tOFF)
0.4(IPEAK)
(1)
Inductance can now be calculated using the peak current:
MINIMUM INDUCTANCE FOR
CONTINOUS MODE OPERATION (µH)
DC =
L=
5V TO 12V
5V TO 18V
2V TO 5V
100
10
10
100
PEAK CURRENT (mA)
1000
1316 F05
Figure 5. Minimum Inductance vs Peak Current
for Continuous Mode Operation
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LT1316
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Discontinuous Mode Operation
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 specification of 0.73, the circuit will need to be designed for
discontinuous operation. Additionally, very low peak current limiting below 50mA may necessitate operating in this
mode unless high inductance values are acceptable. When
operating in discontinuous mode, a different equation
governs available output power. For each switch cycle, the
inductor current ramps down to zero, completely releasing 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:
POUT(MAX) = 1/2L(IPEAK2)f
)
1
Where f = IPEAK(L)
+t
VIN – VSAT OFF
)
)
IPEAK • L
(VIN – VSAT)
2(IOUT) 2(10mA)
=
= 58mA
1 – DC 1 – 0.654
3. Find L
L=
)
)
)
VOUT – VIN + VD
tOFF
0.4(IPEAK)
)
= 5 – 2 + 0.4 2µs
0.4(58mA)
= 293µH
4. Find RSET resistor
Overshoot =
=
) )
) )
VIN
300ns
L
2
= 1.8mA
330µH
Find RSET from Figure 3 for 58mA – 1.8mA = 56.2mA
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:
On-Time =
2. IPEAK =
)
RSET ≈ 47k
Design Example 2
Requirements: VIN = 3.3V, VOUT = 28V and ILOAD = 5mA.
1. Find duty cycle:
DC =
where VSAT = 0.2V.
Also, at these low current levels, current overshoot due to
power transistor turn-off delay will be a significant portion
of peak current. Increasing inductor size will keep this to
a minimum.
)
))
)
VOUT – VIN + VD
= 28 – 3.3 + 0.4 = 0.89
VOUT – VSAT + VD 28 – 0.2 + 0.4
Because duty cycle exceeds LT1316 minimum specification of 73%, the circuit must be designed for discontinuous operation.
2. Find POUT(MAX)
Design Example 1
Multiply POUT by 1.4 to give a safe operating margin
Requirements: VIN = 2V, VOUT = 5V and ILOAD = 10mA.
POUT(MAX) = POUT(1.4) = (5mA)(28V)(1.4) = 0.196W
1. Find duty cycle
DC =
)
))
)
VOUT – VIN + VD
= 5 – 2 + 0.4 = 0.654
VOUT – VSAT + VD 5 – 0.2 + 0.4
Because duty cycle is less than the LT1316 minimum
specification (0.73), the circuit can be designed for
continuous operation.
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3. Set the on-time to the data sheet minimum of 3.4µs and
find L
L=
=
(tON2)(VIN – VSAT)2
2POUT(MAX)(tON + tOFF)
(3.4µs2)(3.3 – 0.2)2
= 52µH
2(0.196W)(3.4µs + 2µs)
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 – VSAT) 3.4µs(3.3 – 0.2)
IPEAK = ON IN
=
L
52µH
= 0.202A
5. Find RSET resistor
Overshoot =
) )
) )
VIN
300ns
L
Diodes
3.3
=
300ns = 19mA
52µH
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
Low ESR (Equivalent Series Resistance) capacitors should
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.
VIN
2
CELLS
Lowering Output Ripple Voltage
To obtain lower output ripple voltage, a small feedforward
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
R1
1M
1%
SW
SHDN
+
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.
+
VOUT
47µF
FB
R2
324k
1%
LT1316
47µF
C1
100pF
RSET
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
100mA/DIV
IL
100mA/DIV
1316 F07
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
The LT1316’s high speed switching mandates careful
attention to PC board layout. Suggested component placement is shown in Figure 9. The input supply must have low
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
1
RSET
1µF ceramic capacitor acts to smooth voltage spikes at
switch turn-on and turn-off. If the power source is far away
from the IC, inductance in the power source leads results
in high impedance at high frequency. A local high capacitance bypass is then required to restore low impedance at
the IC.
Low-Battery Detector
The LT1316 contains an independent low-battery detector
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 comparator also operates below the switcher’s undervoltage lockout threshold, operating until VIN reaches approximately
1.4V.
8
2
LT1316
7
3
6
4
5
VIN
L
+
CIN
D
GND
COUT
+
1316 F09
VOUT
Figure 9. Suggested PC Layout
10
1316 F08
LT1316
U
TYPICAL APPLICATIONS N
Nonisolated – 48V to 5V Flyback Converter
VOUT
5V
50mA
D1
1N5817
T1
10:1:1
3
2
L1
L3
4
1
+ C3
47µF
D2
1N4148
7
L2
6
R1
1.3M
C2
0.022µF
D3
1N4148
VA
Q1
R4
2M
7
C1
0.1µF
Q3
2N3904
R2
1.30M
1%
1
2
+ C4
5
SW
6
VIN
47µF
SHDN
LB0
LT1316
FB
R6
121k
1%
LBI
GND
RSET
3
R5
69.8k
1%
R3
604k
1%
R7
Q2
MPSA92 432k, 1%
8
4
T1 = DALE LPE-4841-A313 (605-665-9301)
L PRI: 2mH
R DS(ON): 4.3Ω AT VGS = 2.5V
R6, Q2,R7 MUST BE PLACED NEXT
TO THE FB PIN
IIN = 190µA WHEN
VIN = 48V, ILOAD = 1mA
1316 • TA03
– 48V
Efficiency vs Load Current
90
80
EFFICIENCY (%)
36VIN
70
48VIN
60
72VIN
50
40
1
10
LOAD CURRENT (mA)
100
1316 TA04
11
LT1316
U
TYPICAL APPLICATIONS N
Positive-to-Negative Converter for LCD Bias
D1
MMBD914
L1
33µH
SHUTDOWN
VIN
6
VIN
7
+
SHDN
C1
33µF
10V
2 CELLS
FB
C3
100pF
50V
C2
0.01µF
50V
5
SW
R1
3.3M
2.2M
8
CONTRAST
ADJUST
R2
210k
LT1316
+
RSET
GND
3
4
C4
1µF
35V
+
C6
0.33µF
50V
C5
2.2µF
35V
D2
MMBD914
R3
15k
VOUT
–20V
6mA
D3
MBR0530L
C4: SPRAGUE 293D105X9035B2T
C5: SPRAGUE 293D225X0035B2T
L1: SUMIDA CD43-330
1316 TA06
Battery-Powered Solenoid Driver
L1
47µH
VCAP
BAT-85
ZTX949
VIN
6
470k
VIN
1
+
2 CELLS
C1
47µF
16V
47k
5
SW
LBO
LBI
2
LT1316
7
SHDN
RSET
3
+
5k
FB
GND
1N4148
6.8M
8
4
324K
C2
470µF
50V
1.3k
SOLENOID
50k
2N3904
VENERGIZE
20k
1316 TA08
C1: AVX TPS 47µF, 16V
C2: SANYO 50MV470GX
L1: SUMIDA CD43-470
CAP SHUTDOWN
GOOD
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
500ms/DIV
12
1316 TA09
LT1316
U
TYPICAL APPLICATIONS N
Super Cap Backup Supply
R1
10k
READY
1M
D1
0.5A
L1
47µH
6
VIN
+
CSUP
+
0.1F
5.5V
75Ω
CONNECT TO
MAIN SUPPLY
5V
6mA
5
SW
1.00M 1 LBO
CIN
33µF
10V
2
357k
7
+
LT1316
LBI
100pF
1.00M
FB
SHDN
RSET
GND
3
4
8
COUT
33µF
10V
324k
RSET
33k
RUN
CIN, COUT: TAJB330M010R
CSUP: PANASONIC EEC-S5R5V104
1316 TA10
D1: MBR0520LT3
L1: SUMIDA CD43-470
50V to 6V Isolated Flyback Converter
T1
LPRI: 2mH 1N5817
10:1:1
+VIN
25V TO
50V
3
4
2
C1
100µF
16V
1
7
510k
0.022µF
100V
CERAMIC
+
+
VOUT
6V/20mA
75% EFFICIENCY
–
1N4148
Q1
1N4148
6
2M
7
0.1µF
1.30M
1%
1
2
2N3904
604k
1%
6
VIN
5
SW
SHDN
LB0
50k
LT1316
FB
8
12.7k
LBI
RSET
GND
3
4
69.8k
1%
1µF
16V
CERAMIC
C1 = SANYO OS-CON 100µF, 16V
Q1 = ZETEX ZVN 4424A
T1 = DALE LPE-4841-A313 (605-665-9301)
1316 TA11
13
LT1316
U
TYPICAL APPLICATIONS N
LCD Bias Generator with Output Disconnect in Shutdown
VBAT
1.6V TO 3.5V
150k
OPTIONAL CONNECTION
L1
22µH
MBR0540LT1
VIN
3.3V
6
+
5
SW
VIN
C1
22µF
6.3V
100pF
50V
CERAMIC
3.32M
1%
FB
Q1
8
VOUT
17.1V TO 19.8V
4mA
LT1316
7
SHUTDOWN
SHDN
RSET
GND
3
4
4.7M
+
232k
1%
0.33µF
50V
CERAMIC
C2
3.3µF
35V
11k
1%
1316 TA12
VADJ
(VOUT ADJUST)
0V TO 3.3V
C1: AVX TAJA226M006R
C2: AVX TAJB335M035R
L1: MURATA LQH3C220K04
Q1: MMBT3906LT3
Universal Serial Bus (USB) to 5V/100mA DC/DC Converter
RB
100Ω
L1
33µH
VIN
4V TO
7V
D1
VOUT
5V
100mA
Q1
7
+
C1
10µF
10V
6
VIN
5
SW
+
SHDN
LT1316
3
RSET
FB
100pF
R2
1.00M
+
C3
10µF
10V
8
GND
R3
10k
C2
33µF
10V
4
R1
324k
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)
0.007
(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)
* 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)
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)
2
3
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
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 circuits as described herein will not infringe on existing patent rights.
4
0.004 – 0.010
(0.101 – 0.254)
0.050
(1.270)
TYP
SO8 0996
15
LT1316
U
TYPICAL APPLICATIONS N
Low Profile 2 Cell-to-28V Converter for LCD Bias
L1
22µH
VIN
7
SHUTDOWN
1
C1
10µF
2 CELLS
2
6
VIN
D1
5
SW
C4
100pF
50V
4.32M
SHDN
LT1316
LBI
VOUT
28V
5mA
FB
LBO
+
8
C3
0.33µF
50V
C2
1µF
35V
204k
RSET
GND
3
4
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
VIN
3.3V TO
4.2V
1N914
6
VIN
7
+
C1
22µF
16V
2N3904
C2
1µF
35V
5
SW
SHDN LT1316
FB
RSET
GND
3
4
100pF
1.00M
C3
1µF
35V
88.7k
+
22k
13V
0.5mA
10k
8
+
47k
BAT54
×2
+
C4
3.3µF
35V
–15V
1.5mA
(BAT54 = TWO DIODES IN SOT23)
1316 TA14
C1: AVX TAJB226M016R
C2, C3: AVX TAJA105K035R
C4: AVX TAJB335M035R
L1: MURATA LQH3C470
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC 1163
Triple High Side Driver for 2-Cell Inputs
1.8V Minimum Input, Drives N-Channel MOSFETs
LTC1174
Micropower Step-Down DC/DC Converter
94% Efficiency, 130µA IQ, 9V to 5V at 300mA
LT1302
High Output Current Micropower DC/DC Converter
5V/600mA from 2V, 2A Internal Switch, 200µA IQ
LT1304
2-Cell Micropower DC/DC Converter
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
LTC1440/1/2
LTC1516
Ultralow Power Single/Dual Comparators with Reference 2.8µA IQ, Adjustable Hysteresis
2-Cell to 5V Regulated Charge Pump
12µA IQ, No Inductors, 5V at 50mA from 3V Input
LT1521
Micropower Low Dropout Linear Regulator
®
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● (408) 432-1900
FAX: (408) 434-0507● TELEX: 499-3977 ● www.linear-tech.com
500mV Dropout, 300mA Current, 12µA IQ
1316f LT/TP 0298 4K • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 1997