EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDEDED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LT1934ES6#PBF
LT1934ES6-1#PBF
LT1934IS6#PBF
LT1934IS6-1#PBF
LT1934IDCB#PBF
LT1934EDCB#PBF
LT1934IDCB-1#PBF
LT1934EDCB-1#PBF
LEAD BASED FINISH
LT1934ES6
LT1934ES6-1
LT1934IS6
LT1934IS6-1
LT1934IDCB
LT1934EDCB
LT1934IDCB-1
LT1934EDCB-1
TAPE AND REEL
LT1934ES6#TRPBF
LT1934ES6-1#TRPBF
LT1934IS6#TRPBF
LT1934IS6-1#TRPBF
LT1934IDCB#TRPBF
LT1934EDCB#TRPBF
LT1934IDCB-1#TRPBF
LT1934EDCB-1#TRPBF
TAPE AND REEL
LT1934ES6#TR
LT1934ES6-1#TR
LT1934IS6#TR
LT1934IS6-1#TR
LT1934IDCB#TR
LT1934EDCB#TR
LT1934IDCB-1#TR
LT1934EDCB-1#TR
S6 PART MARKING*
LTXP
LTF8
LTAJB
LTAJC
LCFZ
LCFZ
LDHC
LDHC
S6 PART MARKING*
LTXP
LTF8
LTAJB
LTAJC
LCFZ
LCFZ
LDHC
LDHC
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
6-Lead (2mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 85°C
–40°C to 125°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/
1934fe
2
LT1934/LT1934-1
ELECTRICAL CHARACTERISTICS
SYMBOL
Undervoltage Lockout
–40°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 125°C
Quiescent Current
V
FB
= 1.3V
–40°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 125°C
V
SHDN
= 0V
FB Comparator Trip Voltage
FB Comparator Hysteresis
FB Pin Bias Current
FB Voltage Line Regulation
Switch Off Time
Maximum Duty Cycle
Switch V
CESAT
V
FB
= 1.25V
4V < V
IN
< 34V
V
FB
> 1V
V
FB
= 0V
V
FB
= 1V
–40°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 125°C
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 10V, V
BOOST
= 15V, unless otherwise noted.
CONDITIONS
l
l
l
l
MIN
TYP
3
3
3
12
12
12
0.01
MAX
3.2
3.6
3.6
22
26
26
2
1.27
1.27
±15
±60
2.3
UNITS
V
V
V
μA
μA
μA
μA
V
V
mV
nA
nA
%/V
μs
μs
%
%
V
FB
Falling
–40°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 125°C
–40°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 125°C
l
l
1.22
1.21
1.25
1.25
10
2
2
0.007
l
l
1.4
85
83
1.8
12
88
88
200
225
65
70
I
SW
= 300mA (LT1934, S6 Package)
I
SW
= 300mA (LT1934, DCB Package)
I
SW
= 75mA (LT1934-1, S6 Package)
I
SW
= 75mA (LT1934-1, DCB Package)
LT1934
LT1934-1
I
SW
= 300mA (LT1934)
I
SW
= 75mA (LT1934-1)
I
SW
= 300mA (LT1934)
I
SW
= 75mA (LT1934-1)
V
SHDN
= 2.3V
V
SHDN
= 34V
2.3
350
90
300
120
490
160
12
10
2.5
2.5
2
mV
mV
mV
mV
mA
mA
mA
mA
V
V
μA
μA
μA
V
V
Switch Current Limit
BOOST Pin Current
Minimum Boost Voltage (Note 3)
Switch Leakage Current
SHDN
Pin Current
SHDN
Input Voltage High
SHDN
Input Voltage Low
400
120
8.5
6.0
1.8
1.7
0.5
1.5
5
0.25
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:
The LT1934E and LT1934E-1 are guaranteed to meet performance
specifications from 0°C to 85°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls. The LT1934I and LT1934I-1
specifications are guaranteed over the –40°C to 125°C temperature range.
Note 3:
This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
1934fe
3
LT1934/LT1934-1
TYPICAL PERFORMANCE CHARACTERISTICS
LT1934 Efficiency, V
OUT
= 5V
100
LT1934
V
OUT
= 5V
L = 47μH
90
T
A
= 25°C
80
100
LT1934 Efficiency, V
OUT
= 3.3V
LT1934
V
OUT
= 3.3V
L = 47μH
90
T
A
= 25°C
80
V
IN
= 24V
V
IN
= 12V
70
100
LT1934-1 Efficiency, V
OUT
= 5V
LT1934-1
V
OUT
= 5V
L = 150μH
T
A
= 25°C
V
IN
= 12V
80
V
IN
= 24V
70
90
V
IN
= 5V
EFFICIENCY (%)
V
IN
= 12V
V
IN
= 24V
EFFICIENCY (%)
EFFICIENCY (%)
70
60
60
60
50
0.1
1
10
100
LOAD CURRENT (mA)
1934 G01
50
0.1
50
1
10
100
LOAD CURRENT (mA)
1934 G02
0.1
1
10
100
1934 G03
LOAD CURRENT (mA)
LT1934-1 Efficiency, V
OUT
= 3.3V
100
500
LT1934-1
V
OUT
= 3.3V
L = 100μH
T
A
= 25°C
V
IN
= 12V
V
IN
= 24V
70
Current Limit vs Temperature
3.0
LT1934
SWITCH CURRENT LIMIT (mA)
400
OFF TIME (μs)
2.5
2.0
1.5
1.0
0.5
Off Time vs Temperature
90
EFFICIENCY (%)
80
300
200
LT1934-1
100
60
50
0.1
1
10
100
1934 G04
0
–50
–25
LOAD CURRENT (mA)
50
25
0
75
TEMPERATURE (°C)
100
125
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
1934 G05
1934 G06
Frequency Foldback
16
14
T
A
= 25 C
1.27
V
FB
vs Temperature
2.0
SHDN
Bias Current
vs
SHDN
Voltage
T
A
= 25°C
SHDN
PIN CURRENT (μA)
1.26
10
8
6
4
2
0
0
0.2
0.8
1.0
0.6
FEEDBACK PIN VOLTAGE (V)
0.4
1.2
1934 G07
FEEDBACK VOLTAGE (V)
SWITCH OFF TIME (μs)
12
1.5
1.25
1.0
1.24
0.5
1.23
1.22
–50
0
–25
50
25
0
75
TEMPERATURE (°C)
100
125
0
2
4
6
8
SHDN
PIN VOLTAGE (V)
10
12
1934 G09
1934 G08
1934fe
4
LT1934/LT1934-1
TYPICAL PERFORMANCE CHARACTERISTICS
Quiescent Current
vs Temperature
20
4.0
Undervoltage Lockout
vs Temperature
QUIESCENT CURRENT (μA)
15
UVLO (V)
75
0
25
50
TEMPERATURE (°C)
100
125
3.5
10
3.0
5
2.5
0
–50
–25
2.0
–50
–25
75
0
25
50
TEMPERATURE (°C)
100
125
1934 G10
1934 G11
Minimum Input Voltage
V
OUT
= 3.3V
6.0
LT1934
V
OUT
= 3.3V
5.5 T
A
= 25°C
BOOST DIODE TIED TO OUTPUT
INPUT VOLTAGE (V)
5.0
4.5
4.0
V
IN
TO RUN
3.5
3.0
0.1
INPUT VOLTAGE (V)
V
IN
TO START
8
Minimum Input Voltage
V
OUT
= 5V
LT1934
V
OUT
= 5V
T
A
= 25°C
7 BOOST DIODE TIED TO OUTPUT
V
IN
TO START
6
V
IN
TO RUN
5
1
10
100
LOAD CURRENT (mA)
1934 G12
4
0.1
1
10
100
LOAD CURRENT (mA)
1934 G13
PIN FUNCTIONS
(TSOT-23/DFN)
BOOST (Pin 1/Pin 1):
The BOOST pin is used to provide a
drive voltage, higher than the input voltage, to the internal
bipolar NPN power switch.
GND (Pin 2/Pin 5):
Tie the GND pin to a local ground plane
below the LT1934 and the circuit components. Return the
feedback divider to this pin.
FB (Pin 3/Pin 6):
The LT1934 regulates its feedback pin
to 1.25V. Connect the feedback resistor divider tap to this
pin. Set the output voltage according to V
OUT
= 1.25V
(1 + R1/R2) or R1 = R2 (V
OUT
/1.25 – 1).
SHDN
(Pin 4/Pin 4):
The
SHDN
pin is used to put the LT1934
in shutdown mode. Tie to ground to shut down the LT1934.
Apply 2.3V or more for normal operation. If the shutdown
feature is not used, tie this pin to the V
IN
pin.
VIN (Pin 5/Pin 3):
The V
IN
pin supplies current to the
LT1934’s internal regulator and to the internal power
switch. This pin must be locally bypassed.
SW (Pin 6/Pin 2):
The SW pin is the output of the internal
power switch. Connect this pin to the inductor, catch diode
程序为顶层程序。如下：
library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity system is
port (clk,fin,en,d,c,b,a:in std_logic;
n:in std_logi ......
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