regulator controller that can directly step-down voltages
from up to 60V, making it ideal for telecom and automo-
tive applications. The LTC3810-5 uses a constant on-time
valley current control architecture to deliver very low duty
cycles with accurate cycle-by-cycle current limit, without
requiring a sense resistor.
A precise internal reference provides 0.5% DC accuracy. A
high bandwidth (25MHz) error amplifier provides very fast
line and load transient response. Large 1Ω gate drivers
allow the LTC3810-5 to drive multiple MOSFETs for higher
current applications. The operating frequency is selected
by an external resistor and is compensated for variations
in V
IN
and can also be synchronized to an external clock
for switching-noise sensitive applications. A shutdown
pin allows the LTC3810-5 to be turned off, reducing the
supply current to 240μA.
Integrated bias control generates gate drive power from
the input supply during start-up or when an output short-
circuit occurs, with the addition of a small external SOT23
MOSFET. When in regulation, power is derived from the
output for higher efficiency.
High Voltage Operation: Up to 60V
Large 1Ω Gate Drivers
No Current Sense Resistor Required
Dual N-Channel MOSFET Synchronous Drive
Extremely Fast Transient Response
±0.5% 0.8V Voltage Reference
Programmable Output Voltage Tracking/Soft-Start
Generates 5.5V Driver Supply from Input Supply
Synchronizable to External Clock
Selectable Pulse Skip Mode Operation
Power Good Output Voltage Monitor
Adjustable On-Time/Frequency: t
ON(MIN)
< 100ns
Adjustable Cycle-by-Cycle Current Limit
Programmable Undervoltage Lockout
Output Overvoltage Protection
Thermally Enhanced 32-Pin QFN Package
APPLICATIONS
n
n
n
48V Telecom and Base Station Power Supplies
Networking Equipment, Servers
Automotive and Industrial Control Systems
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 5481178, 5847554, 6304066, 6476589, 6580258, 6677210, 6774611.
TYPICAL APPLICATION
High Efficiency High Voltage Step-Down Converter
274k
I
ON
PGOOD
V
RNG
1000pF
NDRV
BOOST
TG
0.1μF
SW
EXTV
CC
DRV
CC
INTV
CC
SENSE
+
BG
SENSE
–
SGND
BGRTN
1μF
1k
Si7450DP
MBR1100
14k
Si7450DP
100k
ZXMN10A07F
EFFICIENCY (%)
95
V
IN
= 42V
Efficiency vs Load Current
100
V
IN
= 24V
+
V
IN
13V TO 60V
22μF
LTC3810-5
10μH
V
OUT
12V/6A
MODE/SYNC
SS/TRACK
SHDN
I
TH
200k
V
FB
90
+
270μF
85
0
1
5pF
2
3
4
LOAD CURRENT (A)
5
6
38105 TA01b
47pF
38105 TA01
38105fc
1
LTC3810-5
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
BOOST
SW
24 SENSE
+
23 NC
22 NC
33
21 NC
20 SENSE
–
19 BGRTN
18 BG
17 DRV
CC
9 10 11 12 13 14 15 16
EXTV
CC
SS/TRACK
INTV
CC
NC
NC
SHDN
UVIN
NDRV
I
ON
NC
NC
NC
NC
TG
Supply Voltages
INTV
CC
, DRV
CC
....................................... –0.3V to 14V
(DRV
CC
– BGRTN), (BOOST – SW) ........ –0.3V to 14V
BOOST (Continuous) ............................. –0.3V to 85V
BOOST (≤400ms) .................................. –0.3V to 95V
BGRTN ........................................................ –5V to 0V
EXTV
CC
.................................................. –0.3V to 15V
(EXTV
CC
– INTV
CC
).................................. –12V to 12V
(NDRV – INTV
CC
) Voltage........................... –0.3V to 10V
SW, SENSE
+
Voltage (Continuous) ................ –1V to 70V
SW, SENSE
+
Voltage (400ms) ....................... –1V to 80V
I
ON
Voltage (Continuous) ........................... –0.3V to 70V
I
ON
Voltage (400ms) .................................. –0.3V to 80V
SS/TRACK Voltage ....................................... –0.3V to 5V
PGOOD Voltage ............................................ –0.3V to 7V
V
RNG
, V
ON
, MODE/SYNC,
SHDN,
UVIN Voltages ............................................ –0.3V to 14V
PLL/LPF FB Voltages................................. –0.3V to 2.7V
,
TG, BG, INTV
CC
, EXTV
CC
RMS Currents .................50mA
Operating Temperature Range (Note 2)
LTC3810E-5 ......................................... –40°C to 85°C
LTC3810I-5 ........................................ –40°C to 125°C
Junction Temperature (Notes 3, 7)........................ 125°C
Storage Temperature Range................... –65°C to 125°C
32 31 30 29 28 27 26 25
NC 1
V
ON
2
V
RNG
3
PGOOD 4
MODE/SYNC 5
I
TH
6
V
FB
7
PLL/LPF 8
UH PACKAGE
32-LEAD (5mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 33) IS SGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3810EUH-5#PBF
LTC3810EUH-5#TRPBF
38105
32-Lead (5mm
×
5mm) Plastic QFN
–40°C to 85°C
LTC3810IUH-5#PBF
LTC3810IUH-5#TRPBF
38105
32-Lead (5mm
×
5mm) Plastic QFN
–40°C to 125°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3810EUH-5
LTC3810EUH-5#TR
38105
32-Lead (5mm
×
5mm) Plastic QFN
–40°C to 85°C
LTC3810IUH-5
LTC3810IUH-5#TR
38105
32-Lead (5mm
×
5mm) Plastic QFN
–40°C to 125°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/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
38105fc
2
LTC3810-5
ELECTRICAL CHARACTERISTICS
SYMBOL
Main Control Loop
INTV
CC
I
Q
I
BOOST
V
FB
PARAMETER
INTV
CC
Supply Voltage
INTV
CC
Supply Current
INTV
CC
Shutdown Current
BOOST Supply Current
Feedback Voltage
The
l
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, INTV
CC
= DRV
CC
= V
BOOST
= V
ON
= V
RNG
=
SHDN
= UV
IN
= V
EXTVCC
= V
NDRV
= 5V, V
MODE/SYNC
= V
SENSE
+
= V
SENSE
–
= V
BGRTN
= V
SW
= 0V, unless otherwise specified.
CONDITIONS
l
MIN
4.35
TYP
MAX
14
6
600
400
5
0.804
0.806
0.806
0.808
0.02
384
120
260
UNITS
V
mA
μA
μA
μA
V
V
V
V
%/V
mV
mV
mV
mV
mV
mV
nA
dB
MHz
V
μA
V
μA
V
V
V
V
V
V
V
μs
ns
ns
ns
μs
μs
μA
μA
A
Ω
A
Ω
38105fc
ΔV
FB,LINE
V
SENSE(MAX)
Feedback Voltage Line Regulation
Maximum Current Sense Threshold
V
SENSE(MIN)
Minimum Current Sense Threshold
I
VFB
A
VOL
(EA)
f
U
V
MODE/SYNC
I
MODE/SYNC
V
SHDN
I
SHDN
V
UVIN
Feedback Current
Error Amplifier DC Open Loop Gain
Error Amp Unity-Gain Crossover
Frequency
MODE/SYNC Threshold
MODE/SYNC Current
Shutdown Threshold
SHDN
Pin Input Current
UVIN Undervoltage Lockout
SHDN
> 1.5V (Notes 4, 5)
SHDN
= 0V
SHDN
> 1.5V (Note 5)
SHDN
= 0V
(Note 4)
0°C to 85°C
–40°C to 85°C
–40°C to 125°C (I-Grade)
5V < INTV
CC
< 14V (Note 4)
V
RNG
= 2V, V
FB
= 0.76V
V
RNG
= 0V, V
FB
= 0.76V
V
RNG
= INTV
CC
, V
FB
= 0.76V
V
RNG
= 2V, V
FB
= 0.84V
V
RNG
= 0V, V
FB
= 0.84V
V
RNG
= INTV
CC
, V
FB
= 0.84V
V
FB
= 0.8V
(Note 6)
V
MODE/SYNC
Rising
MODE/SYNC = 5V
l
l
l
l
0.796
0.794
0.792
0.792
256
70
170
65
3
240
270
0
0.800
0.800
0.800
0.800
0.002
320
95
215
–300
–85
–200
20
100
25
0.8
0
1.5
0
0.89
0.80
0.10
4.2
4.2
9
3.7
1.85
605
250
150
0.75
1.2
UVIN Rising
UVIN Falling
Hysteresis
INTV
CC
Rising, I
NDRV
= 100μA
INTV
CC
Rising, NDRV = INTV
CC
= EXTV
CC
INTV
CC
Rising, NDRV = INTV
CC
, EXTV
CC
= 0
INTV
CC
Falling
I
ON
= 100μA
I
ON
= 300μA
I
ON
= 2000μA
l
l
0.86
0.78
0.07
4.05
4.05
8.70
0.85
1
2
1
0.92
0.82
0.12
4.35
4.35
9.30
V
VCCUV
INTV
CC
Undervoltage Lockout
Linear Regulator Mode
External Supply Mode
Trickle-Charge Mode
l
l
l
Oscillator and Phase-Locked Loop
t
ON
On-Time
t
ON(MIN)
t
OFF(MIN)
t
ON(PLL)
Minimum On-Time
Minimum Off-Time
t
ON
Modulation Range by PLL
Down Modulation
Up Modulation
Phase Detector Output Current
Sinking Capability
Sourcing Capability
BG Driver Peak Source Current
BG Driver Pull-Down R
DS(ON)
TG Driver Peak Source Current
TG Driver Pull-Down R
DS(ON)
1.55
515
2.15
695
100
350
5
1.8
I
ON
= 100μA, V
PLL/LPF
= 0.6V
I
ON
= 100μA, V
PLL/LPF
= 1.8V
f
PLLIN
< f
SW
f
PLLIN
> f
SW
V
BG
= 0V
V
TG
– V
SW
= 0
2.2
0.6
3.6
1.2
15
–25
I
PLL/LPF
Driver
I
BG,PEAK
R
BG,SINK
I
TG,PEAK
R
TG,SINK
0.7
0.7
1
1
1
1
1.5
1.5
3
LTC3810-5
ELECTRICAL CHARACTERISTICS
SYMBOL
PGOOD Output
ΔV
FBOV
ΔV
FB,HYST
V
PGOOD
I
PGOOD
PG Delay
Tracking
I
SS/TRACK
V
FB,TRACK
V
CC
Regulators
V
EXTVCC
PARAMETER
PGOOD Upper Threshold
PGOOD Lower Threshold
PGOOD Hysterisis
PGOOD Low Voltage
PGOOD Leakage Current
PGOOD Delay
SS/TRACK Source Current
Feedback Voltage at Tracking
The
l
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, INTV
CC
= DRV
CC
= V
BOOST
= V
ON
= V
RNG
=
SHDN
= UV
IN
= V
EXTVCC
= V
NDRV
= 5V, V
MODE/SYNC
= V
SENSE
+
= V
SENSE
–
= V
BGRTN
= V
SW
= 0V, unless otherwise specified.
CONDITIONS
V
FB
Rising
V
FB
Falling
V
FB
Returning
I
PGOOD
= 5mA
V
PGOOD
= 5V
V
FB
Falling
V
SS/TRACK
> 0.5V
V
TRACK
= 0V, I
TH
= 1.2V (Note 4)
V
TRACK
= 0.5V, I
TH
= 1.2V (Note 4)
MIN
7.5
–7.5
TYP
10
–10
1.5
0.3
0
120
1.4
–0.018
0.5
MAX
12.5
–12.5
3
0.6
2
UNITS
%
%
%
V
μA
μs
μA
V
V
0.7
0.48
2.5
0.52
V
INTVCC,1
ΔV
EXTVCC,1
ΔV
LOADREG,1
V
INTVCC,2
ΔV
LOADREG,2
I
NDRV
I
NDRVTO
V
CCSR
I
CCSR
EXTV
CC
Switchover Voltage
EXTV
CC
Rising
EXTV
CC
Hysterisis
INTV
CC
Voltage from EXTV
CC
V
EXTVCC
- V
INTVCC
at Dropout
INTV
CC
Load Regulation from EXTV
CC
INTV
CC
Voltage from NDRV Regulator
INTV
CC
Load Regulation from NDRV
Current into NDRV Pin
Linear Regulator Timeout Enable
Threshold
Maximum Supply Voltage
Maximum Current into NDRV/INTV
CC
l
6V < V
EXTVCC
< 15V
I
CC
= 20mA, V
EXTVCC
= 5V
I
CC
= 0mA to 20mA, V
EXTVCC
= 10V
Linear Regulator in Operation
I
CC
= 0mA to 20mA, V
EXTVCC
= 0
V
NDRV
– V
INTVCC
= 3V
4.45
0.1
5.2
5.2
20
210
4.7
0.25
5.5
75
0.01
5.5
0.01
40
270
15
0.4
5.8
150
5.8
60
350
V
V
V
mV
%
V
%
μA
μA
V
mA
Trickle Charger Shunt Regulator
Trickle Charger Shunt Regulator,
INTV
CC
≤ 16.7V (Note 8)
10
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 LTC3810E-5 is 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 LTC3810I-5 is guaranteed to meet
performance specifications over the full –40°C to 125°C operating
temperature range.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3810-5: T
J
= T
A
+ (P
D
• 34°C/W)
PARAMETER
Maximum V
IN
MOSFET Gate Drive
INTV
CC
UV
+
INTV
CC
UV
–
LTC3810
100V
6.35V to 14V
6.2V
6V
Note 4:
The LTC3810-5 is tested in a feedback loop that servos V
FB
to the
reference voltage with the I
TH
pin forced to a voltage between 1V and 2V.
Note 5:
The dynamic input supply current is higher due to the power
MOSFET gate charging being delivered at the switching frequency
(Q
G
• f
OSC
).
Note 6:
Guaranteed by design. Not subject to test.
Note 7:
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 junction
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