LTC3830/LTC3830-1
High Power Step-Down
Synchronous DC/DC Controllers
for Low Voltage Operation
FEATURES
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DESCRIPTIO
High Power Switching Regulator Controller
for 3.3V-5V to 1.xV-3.xV Step-Down Applications
No Current Sense Resistor Required
Low Input Supply Voltage Range: 3V to 8V
Maximum Duty Cycle > 91% Over Temperature
All N-Channel External MOSFETs
Excellent Output Regulation:
±1%
Over Line, Load
and Temperature Variations
High Efficiency: Over 95% Possible
Adjustable or Fixed 3.3V Output (16-Pin Version)
Programmable Fixed Frequency Operation: 100kHz to
500kHz
External Clock Synchronization
Soft-Start (16-Pin Version and LTC3830-1)
Low Shutdown Current: <10µA
Overtemperature Protection
Available in S8, S16 and SSOP-16 Packages
The LTC
®
3830/LTC3830-1 are high power, high effi-
ciency switching regulator controllers optimized for
3.3V-5V to 1.xV-3.xV step-down applications. A preci-
sion internal reference and feedback system provide
±1%
output regulation over temperature, load current
and line voltage variations. The LTC3830/LTC3830-1 use
a synchronous switching architecture with N-channel
MOSFETs. Additionally, the chip senses output current
through the drain-source resistance of the upper
N-channel FET, providing an adjustable current limit
without a current sense resistor.
The LTC3830/LTC3830-1 operate with an input supply
voltage as low as 3V and with a maximum duty cycle of
>91% over temperature. They include a fixed frequency
PWM oscillator for low output ripple operation. The 200kHz
free-running clock frequency can be externally adjusted or
synchronized with an external signal from 100kHz to 500kHz.
In shutdown mode, the LTC3830 supply current drops to
<10µA. The LTC3830-1 differs from the LTC3830 S8 ver-
sion by replacing shutdown with a soft-start function.
For a similar, pin compatible DC/DC converter with an
output voltage as low as 0.6V, please refer to the LTC3832.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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CPU Power Supplies
Multiple Logic Supply Generator
Distributed Power Applications
High Efficiency Power Conversion
TYPICAL APPLICATIO
4.7µF
V
IN
3V TO 6V
5.1Ω
Efficiency and Power Loss vs Load Current
+
4.0
100
90
80
0.1µF
0.01µF
15k
220µF
10V
3.5
3.0
G1
COMP
0.1µF
GND PV
CC1
M1
Si7806DN
L
3.2µH
1.8V
9A
M2
Si7806DN
B320A
POWER LOSS (W)
LTC3830-1
PV
CC2
SS
MBR0520T1
2.5
2.0
1.5
1.0
0.5
0
0
1
2
12.7k 1%
FB
5.36k 1%
3.3nF
G2
+
C
OUT
270µF
2V
3830 F01
L: SUMIDA CDEP105-3R2MC-88
C
OUT
: PANASONIC EEFUEOD271R
Figure 1. High Efficiency 3V-6V to 1.8V Power Converter
U
EFFICIENCY (%)
70
60
50
40
30
V
IN
= 3.3V
V
OUT
= 1.8V
20
3 4 5 6 7 8 9 10
LOAD CURRENT (A)
3830 TA02
U
U
3830fa
1
LTC3830/LTC3830-1
ABSOLUTE
AXI U
RATI GS
Supply Voltage
V
CC
....................................................................... 9V
PV
CC1,2
................................................................ 14V
Input Voltage
I
FB
, I
MAX
............................................... – 0.3V to 14V
SENSE
+
, SENSE
–
, FB,
SHDN, FREQSET ....................... – 0.3V to V
CC
+ 0.3V
PACKAGE/ORDER I FOR ATIO
TOP VIEW
G1 1
PV
CC1
2
GND 3
FB 4
8
7
6
5
G2
V
CC
/PV
CC2
COMP
SHDN
ORDER PART
NUMBER
LTC3830ES8
G1
1
2
3
4
5
6
7
8
TOP VIEW
16 G2
15 PV
CC2
14 V
CC
13 I
FB
12 I
MAX
11 FREQSET
10 COMP
9
SS
S8 PACKAGE
8-LEAD PLASTIC SO
S8
PART MARKING
3830
ORDER PART
NUMBER
LTC3830-1ES8
S8
PART MARKING
38301
T
JMAX
= 125°C,
θ
JA
= 130°C/ W
TOP VIEW
G1 1
PV
CC1
2
GND 3
FB 4
8
7
6
5
G2
V
CC
/PV
CC2
COMP
SS
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 130°C/ W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
●
denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. V
CC
, PV
CC1
, PV
CC2
= 5V, unless otherwise noted. (Note 2)
SYMBOL
V
CC
PV
CC
V
UVLO
V
FB
V
OUT
∆V
OUT
PARAMETER
Supply Voltage
PV
CC1
, PV
CC2
Voltage
Undervoltage Lockout Voltage
Feedback Voltage
Output Voltage
Output Load Regulation
Output Line Regulation
V
COMP
= 1.25V
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
●
(Note 7)
V
COMP
= 1.25V
●
I
OUT
= 0A to 10A (Note 6)
V
CC
= 4.75V to 5.25V
2
U
U
W
W W
U
W
(Note 1)
Junction Temperature (Note 11) ........................... 125°C
Operating Temperature Range (Note 9) .. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC3830EGN
LTC3830ES
GN PART
MARKING
3830
PV
CC1
PGND
GND
SENSE
–
FB
SENSE
+
SHDN
GN PACKAGE
S PACKAGE
16-LEAD PLASTIC SSOP 16-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 130°C/ W (GN)
T
JMAX
= 125°C,
θ
JA
= 100°C/ W (S)
MIN
3
3
●
TYP
5
2.4
MAX
8
13.2
2.9
1.275
1.278
3.350
3.365
UNITS
V
V
V
V
V
V
V
mV
mV
3830fa
1.255
1.252
3.250
3.235
1.265
1.265
3.3
3.3
2
0.1
LTC3830/LTC3830-1
The
●
denotes specifications that apply over the full operating temperature
range, otherwise specifications are at T
A
= 25°C. V
CC
, PV
CC1
, PV
CC2
= 5V, unless otherwise noted. (Note 2)
SYMBOL
I
VCC
I
PVCC
f
OSC
V
SAWL
V
SAWH
V
COMPMAX
A
V
g
m
I
COMP
I
MAX
PARAMETER
Supply Current
PV
CC
Supply Current
Internal Oscillator Frequency
V
COMP
at Minimum Duty Cycle
V
COMP
at Maximum Duty Cycle
Maximum V
COMP
Error Amplifier Open-Loop DC Gain
Error Amplifier Transconductance
Error Amplifier Output Sink/Source Current
I
MAX
Sink Current
I
MAX
Sink Current Tempco
V
IH
V
IL
I
IN
I
SS
I
SSIL
R
SENSE
R
SENSEFB
t
r
, t
f
t
NOV
DC
MAX
SHDN Input High Voltage
SHDN Input Low Voltage
SHDN Input Current
Soft-Start Source Current
Maximum Soft-Start Sink Current
In Current Limit
SENSE Input Resistance
SENSE to FB Resistance
Driver Rise/Fall Time
Driver Nonoverlap Time
Maximum G1 Duty Cycle
Figure 3, PV
CC1
= PV
CC2
= 5V (Note 5)
Figure 3, PV
CC1
= PV
CC2
= 5V (Note 5)
Figure 3, V
FB
= 0V (Note 5), PV
CC1
= 8V
●
●
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
Figure 2, V
SHDN
= V
CC
V
SHDN
= 0V
Figure 2, V
SHDN
= V
CC
(Note 3)
V
SHDN
= 0V
FREQSET Floating
●
●
●
●
●
MIN
TYP
0.7
1
14
0.1
MAX
1.6
10
20
10
250
UNITS
mA
µA
mA
µA
kHz
V
V
V
kHz/µA
dB
160
200
1.2
2.2
V
FB
= 0V, PV
CC1
= 8V
Measured from FB to COMP,
SENSE
+
and SENSE
–
Floating, (Note 4)
Measured from FB to COMP,
SENSE
+
and SENSE
–
Floating, (Note 4)
V
IMAX
= V
CC
(Note 10)
V
IMAX
= V
CC
(Note 6)
●
●
●
●
2.85
10
46
520
55
650
100
●
∆f
OSC
/∆I
FREQSET
Frequency Adjustment
780
µmho
µA
9
4
2.4
12
12
3300
15
20
µA
µA
ppm/°C
V
0.8
0.1
–8
–12
1.6
29.2
18
80
25
91
120
95
250
250
1
–16
V
µA
µA
mA
kΩ
kΩ
ns
ns
%
V
SHDN
= V
CC
V
SS
= 0V, V
IMAX
= 0V, V
IFB
= V
CC
V
IMAX
= V
CC
, V
IFB
= 0V,
V
SS
= V
CC
(Note 8), PV
CC1
= 8V
●
●
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3:
Supply current in normal operation is dominated by the current
needed to charge and discharge the external FET gates. This will vary with
the LTC3830 operating frequency, operating voltage and the external FETs
used.
Note 4:
The open-loop DC gain and transconductance from the SENSE
+
and SENSE
–
pins to COMP pin will be (A
V
)(1.265/3.3) and (g
m
)(1.265/3.3)
respectively.
Note 5:
Rise and fall times are measured using 10% and 90% levels. Duty
cycle and nonoverlap times are measured using 50% levels.
Note 6:
Guaranteed by design, not subject to test.
Note 7:
PV
CC1
must be higher than V
CC
by at least 2.5V for G1 to operate
at 95% maximum duty cycle and for the current limit protection circuit to
be active.
Note 8:
The current limiting amplifier can sink but cannot source current.
Under normal (not current limited) operation, the output current will be
zero.
Note 9:
The LTC3830E/LTC3830-1E are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 10:
The minimum and maximum limits for I
MAX
over temperature
includes the intentional temperature coefficient of 3300ppm/°C. This
induced temperature coefficient counteracts the typical temperature
coefficient of the external power MOSFET on-resistance. This results in a
relatively flat current limit over temperature for the application.
Note 11:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating temperature
may impair device reliability.
3830fa
3
LTC3830/LTC3830-1
TYPICAL PERFOR A CE CHARACTERISTICS
Load Regulation
3.34
3.33
3.32
T
A
= 25°C
REFER TO FIGURE 12
1.275
1.273
1.271
1.269
T
A
= 25°C
10
8
6
4
ERROR AMPLIFIER TRANSCONDUCTANCE (µmho)
V
OUT
(V)
3.31
3.30
3.29
3.28
3.27
3.26
–15
–10
5
0
OUTPUT CURRENT (A)
–5
10
15
3830 G02
V
FB
(V)
Output Voltage Temperature Drift
ERROR AMPLIFIER SINK/SOURCE CURRENT (µA)
3.34
3.33
3.32
V
OUT
(V)
30
20
10
0
–10
–20
–30
∆V
OUT
(mV)
180
160
140
120
100
80
60
40
–50 –25
0
50
75
25
TEMPERATURE (°C)
100
125
ERROR AMPLIFIER OPEN-LOOP GAIN (dB)
REFER TO FIGURE 12
OUTPUT = NO LOAD
3.31
3.30
3.29
3.28
3.27
3.26
–50 –25
0
50
75
25
TEMPERATURE (°C)
100
Oscillator Frequency
vs Temperature
250
240
OSCILLATOR FREQUENCY (kHz)
OSCILLATOR FREQUENCY (kHz)
600
FREQSET FLOATING
500
400
300
200
100
0
–40
230
220
210
200
190
180
170
160
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
V
SAWH
– V
SAWL
(V)
4
U W
3830 G04
Line Regulation
800
750
700
650
600
550
Error Amplifier Transconductance
vs Temperature
∆V
FB
(mV)
1.267
1.265
1.263
1.261
1.259
1.257
1.255
3
4
6
7
5
SUPPLY VOLTAGE (V)
8
3830 G03
2
0
–2
–4
–6
–8
–10
500
–50 –25
50
25
75
0
TEMPERATURE (˚C)
100
125
3830 G05
Error Amplifier Sink/Source
Current vs Temperature
40
200
Error Amplifier Open-Loop Gain
vs Temperature
60
55
50
45
–40
125
40
–50 –25
75
0
25
50
TEMPERATURE (°C)
100
125
3830 G06
2830 G07
Oscillator Frequency
vs FREQSET Input Current
1.5
Oscillator (V
SAWH
– V
SAWL
)
vs External Sync Frequency
T
A
= 25°C
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
T
A
= 25°C
10
–20
–10
0
–30
FREQSET INPUT CURRENT (µA)
20
3830 G09
0.5
100
300
200
400
EXTERNAL SYNC FREQUENCY (kHz)
500
3831 G08
3830 G10
3830fa
LTC3830/LTC3830-1
TYPICAL PERFOR A CE CHARACTERISTICS
Maximum G1 Duty Cycle
vs Temperature
100
99
MAXIMUM G1 DUTY CYCLE (%)
V
FB
= 0V
REFER TO FIGURE 3
I
MAX
SINK CURRENT (µA)
98
97
96
95
94
93
92
91
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
OUTPUT VOLTAGE (V)
Output Current Limit Threshold
vs Temperature
16
SOFT-START SOURCE CURRENT (µA)
12
10
8
6
4
REFER TO FIGURE 12 AND NOTE 10 OF
2 THE ELECTRICAL CHARACTERISTICS
R
IMAX
= 5k
0
50
25
0
75 100
–50 –25
TEMPERATURE (°C)
–10
–11
–12
–13
–14
–15
–16
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
100
125
SOFT-START SINK CURRENT (mA)
14
OUTPUT CURRENT LIMIT (A)
UNDERVOLTAGE LOCKOUT THRESHOLD VOLTAGE (V)
Undervoltage Lockout Threshold
Voltage vs Temperature
3.0
1.6
V
CC
OPERATING SUPPLY CURRENT (mA)
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
PV
CC
SUPPLY CURRENT (mA)
U W
3830 G11
3830 G14
3830 G17
I
MAX
Sink Current
vs Temperature
20
18
16
14
12
10
8
6
4
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
100
125
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Output Overcurrent Protection
T
A
= 25°C
0.5 REFER TO FIGURE 12
R
IMAX
= 5k
0
2
4
6
8
10
0
OUTPUT CURRENT (A)
12
14
3830 G12
3830 G13
Soft-Start Source Current
vs Temperature
–8
–9
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
Soft-Start Sink Current
vs (V
IFB
– V
IMAX
)
T
A
= 25°C
125
0
–150
–125
–100
–50
–75
V
IFB
– V
IMAX
(mV)
–25
0
3830 G16
3830 G15
V
CC
Operating Supply Current
vs Temperature
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
–50
–25
50
25
0
75
TEMPERATURE (°C)
100
125
FREQSET FLOATING
90
80
70
60
50
40
30
20
10
0
PV
CC
Supply Current
vs Oscillator Frequency
T
A
= 25°C
G1 AND G2 LOADED
WITH 6800pF,
PV
CC1,2
= 12V
G1 AND G2
LOADED
WITH 1000pF,
PV
CC1,2
= 5V
G1 AND G2
LOADED
WITH 6800pF,
PV
CC1,2
= 5V
0
400
100
300
200
OSCILLATOR FREQUENCY (kHz)
500
3830 G19
3830 G18
3830fa
5
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