High Efficiency Dual Phase 1.5V/60A Step-Down Converter
RUN1, 2
ILIM1, 2
HIZB1
HIZB2
PWM1
PWMEN1
V
OSNS1–
SNSA1
+
SNS1
–
SNSD1
+
V
OSNS1+
I
TH1
TK/SS1
V
IN
PHSMD
CLKOUT
PGOOD1,2
MODE/PLLIN
PWM2
PWMEN2
GND
V
OSNS2–
SNSA2
+
SNS2
–
SNSD2
+
FREQ
V
OSNS2+
I
TH2
37.5k
330µF
4V
22µF
50V
f
IN
500kHz
DRMOS
0.33µH
(0.32mΩ DCR)
V
IN
4.5V TO 20V
1/4 INTV
CC
0.33µH
(0.32mΩ DCR)
DRMOS
LTC3774
15k
300µF
4V
+
10k
2200pF
15k
TK/SS2
INTV
CC
V
OUT
1.5V
60A
+
0.1µF
4.7µF
3774 TA01a
3774fc
For more information
www.linear.com/LTC3774
1
LTC3774
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
MODE/PLLIN
CLKOUT
V
IN
Voltage ................................................. –0.3V to 40V
HIZB Voltage .............................................. –0.3V to 40V
RUN, PGOOD, INTV
CC
Voltage ..................... –0.3V to 6V
SNSA1
+
, SNSA2
+
, SNSD1
+
,
SNSD2
+
, SNS1
–
, SNS2
–
........................ –0.3V to INTV
CC
INTV
CC
Peak Output Current ..................................20mA
All Other Pin Voltages ........................... –0.3V to INTV
CC
Operating Junction Temperature Range
(Note 2).................................................. –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
PHSMD
SNS1
–
INTV
CC
ILIM2
36 35 34 33 32 31 30 29
ITEMP2 1
ITH2 2
V
OSNS2
–
ILIM1
28 ITEMP1
27 ITH1
26 V
OSNS1–
25 V
OSNS1+
24 TK/SS1
23 HIZB1
22 PWMEN1
21 PWM1
20 RUN1
19 GND
SNSD1
+
3
V
OSNS2+
4
TK/SS2 5
HIZB2 6
PWMEN2 7
PWM2 8
RUN2 9
GND 10
11 12 13 14 15 16 17 18
PGOOD2
PGOOD1
SNSD2
+
SNS2
–
SNSA2
+
SNSA1
+
37
GND
UHE PACKAGE
36-LEAD (5mm × 6mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 37) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3774EUHE#PBF
LTC3774IUHE#PBF
TAPE AND REEL
LTC3774EUHE#TRPBF
LTC3774IUHE#TRPBF
http://www.linear.com/product/LTC3774#orderinfo
PART MARKING*
3774
3774
PACKAGE DESCRIPTION
36-Lead (5mm
×
6mm) Plastic QFN
36-Lead (5mm
×
6mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 125°C
–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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
FREQ
V
IN
2
3774fc
For more information
www.linear.com/LTC3774
LTC3774
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V unless otherwise specified.
SYMBOL
V
IN
V
OUT
V
OSNS+
I
OSNS+
V
REFLNREG
V
LOADREG
g
m
f
0dB
V
OVL
I
Q
DF
MAX
UVLO
UVLO
HYS
I
SNSA+
I
SNSD+
I
SNS–
A
VT_SNS
I
TEMP
I
TK/SS
t
SS(INTERNAL)
V
HIZB
V
HIZB_HYS
V
RUN
V
RUN_HYS
I
RUN
V
SENSE(MAX)
PARAMETER
Input Voltage Range
Output Voltage Range
Regulated Feedback Voltage
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
Transconductance Amplifier g
m
DA Unity-Gain Crossover Frequency
Feedback Overvoltage Lockout
Input DC Supply Current
Normal Mode
Shutdown
Maximum Duty Factor
Undervoltage Lockout
UVLO Hysteresis
Sense Pin Bias Currents
Sense Pin Bias Currents
Sense Pin Bias Currents
Total Sense Signal Gain to Current
Comparator
DCR Tempco Compensation Current
Soft-Start Charge Current
Internal Soft-Start Time
HIZB Pin On Threshold
HIZB Pin On Hysteresis
RUN Pin On Threshold
RUN Pin On Hysteresis
RUN Pin Pull-Up Current
RUN < On Threshold
RUN > On Threshold
Maximum Current Sense Threshold
RUN < 1.1V
RUN > 1.34V
I
TH
= 2V, V
SNS
– = 3.3V
I
LIM
= 0V
I
LIM
= 1/4 INTV
CC
I
LIM
= Float
I
LIM
= 3/4 INTV
CC
I
LIM
= INTV
CC
l
l
l
l
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
4.5
0.6
595.5
TYP
MAX
38
3.5
UNITS
V
V
mV
nA
%/V
%
%
mmho
MHz
Main Control Loop/Whole System
I
TH
= 1.2V (Note 3)
V
IN
= 4.5V to 38V
∆I
TH
= 1.2V to 0.7V
∆I
TH
= 1.2V to 1.6V
I
TH
= 1.2V, Sink/Source 5µA
(Note 5)
Measured at V
OSNS+
(Note 4)
V
RUN
= 0V
In Dropout
V
INTVCC
Falling
V
SNSA+
= 3.3V
V
SNSD+
= 3.3V
V
SNS–
= 3.3V
l
600
–30
0.002
604.5
–100
0.01
0.1
0.1
l
l
0.01
0.01
2
4
l
5
7.5
9
40
10
%
mA
µA
%
V
mV
µA
nA
µA
V/V
60
4.0
±2
96
3.5
98
3.75
500
±0.5
30
10
5
V
ITEMP
= 0.5V
V
TK/SS
= 0V
V
TK/SS
= 5V
V
HIZB
Rising
V
RUN
Rising
l
l
27
1
30
1.25
600
2.2
600
33
1.5
µA
µA
µs
V
mV
l
1.1
1.22
80
1
5
1.34
V
mV
µA
µA
9.25
14
19
24
28.25
10.25
15
20
25
29.75
90
11.25
16
21
26
31.25
200
2
mV
mV
mV
mV
mV
Ω
µA
µs
Power Good
V
PGOOD(ON)
I
PGOOD(OFF)
t
PGOOD
V
PGOOD
PGOOD Pull-Down Resistance
PGOOD Leakage Current
V
PGOOD
High to Low Delay
PGOOD Trip Level
V
OSNS
+ with Respect to Set Output Voltage
V
OSNS
+ Ramping Up
V
OSNS
+ Ramping Down
5
–5
V
PGOOD
= 5V
–2
45
7.5
–7.5
10
–10
%
%
3774fc
For more information
www.linear.com/LTC3774
3
LTC3774
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V unless otherwise specified.
SYMBOL
V
PG(HYST)
V
INTVCC
V
LDO
INT
f
OSC
PARAMETER
PGOOD Trip Level Hysteresis
Linear Regulator Voltage
INTV
CC
Load Regulation
Oscillator Frequency
V
PHSMD
= 0V
6V < V
IN
< 38V
I
CC
= 0mA to 20mA
R
FREQ
< 23.2kΩ
R
FREQ
= 30.1kΩ
R
FREQ
= 47.5kΩ
R
FREQ
= 54.9kΩ
R
FREQ
= 75.0kΩ
Maximum Frequency
Minimum Frequency
V
FREQ
= 0.8V
V
MODE/PLLIN
Rising
V
MODE/PLLIN
Falling
I
LOAD
= –500µA
I
LOAD
= 500µA
V
PHSMD
= 0V
V
PHSMD
= 1/4 INTV
CC
V
PHSMD
= Float
V
PHSMD
= 3/4 INTV
CC
V
PHSMD
= INTV
CC
V
PHSMD
= 0V
V
PHSMD
= 1/4 INTV
CC
V
PHSMD
= Float
V
PHSMD
= 3/4 INTV
CC
V
PHSMD
= INTV
CC
V
PHSMD
= 0V
V
PHSMD
= 1/4 INTV
CC
V
PHSMD
= Float
V
PHSMD
= 3/4 INTV
CC
V
PHSMD
= INTV
CC
I
LOAD
= 500µA
I
LOAD
= –500µA
I
LOAD
= 500µA
l
l
l
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
TYP
2
MAX
UNITS
%
INTV
CC
Linear Regulator
5.3
5.5
0.5
150
250
600
750
1.05
5.7
2
V
%
kHz
kHz
kHz
kHz
MHz
MHz
MHz
µA
kΩ
V
V
V
V
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
Deg
V
0.5
–5
5.0
5
V
µA
V
Oscillator and Phase-Locked Loop
540
l
l
660
1.2
19
0.2
20
250
2
1.2
0.2
5.2
180
180
180
180
120
60
60
90
45
240
0
90
0
0
0
21
I
FREQ
R
MODE/PLLIN
V
MODE/PLLIN
V
CLKOUT
θ
2
–
θ
1
FREQ Pin Output Current
MODE/PLLIN Input Resistance
PLLIN Input Threshold
Low Output Voltage
High Output Voltage
Channel 1-2 Phase Delay
θ
CLKOUT
–
θ
1
CLKOUT to Channel 1
Phase Delay
θ
1
–
θ
CLKIN
Channel 1 to CLKIN Phase Delay
PWM/PWMEN Outputs
PWM
PWM Output High Voltage
PWM Output Low Voltage
PWM Output Current in Hi-Z State
PWMEN
PWMEN Output High Voltage
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 LTC3774 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3774E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC3774I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range. The maximum
ambient temperature consistent with these specifications is determined by
5.0
specific operating conditions in conjunction with board layout, the package
thermal impedance and other environmental factors.
T
J
is calculated from the ambient temperature, T
A
, and power dissipation,
P
D
, according to the following formula:
LTC3774UHE: T
J
= T
A
+ (P
D
• 43°C/W)
Note 3:
The LTC3774 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 4:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
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