(Notes 2, 3) ............................................ –40°C to 150°C
Storage Temperature Range .................. –65°C to 150°C
pin conFiguraTion
TOP VIEW
TOP VIEW
MODE
TEMP
EN1
EN2
EN7
EN8
V
CC
TEMP
EN2
EN1
31 FB8
30 V
IN8
29 SW8
28 SW7
27 V
IN7
39
GND
26 FB7
25 FB6
24 V
IN6
23 SW6
22 SW5
21 V
IN5
20 FB5
13 14 15 16 17 18 19
EN4
EN3
SYNC
RT
EN6
PGOOD_ALL
EN5
FB1
V
IN1
SW1
SW2
V
IN2
FB2
1
2
3
4
5
6
7
8
9
39
GND
38 V
CC
37 MODE
36 EN7
35 EN8
34 FB8
33 V
IN8
32 SW8
31 SW7
30 V
IN7
29 FB7
28 FB6
27 V
IN6
26 SW6
25 SW5
24 V
IN5
23 FB5
22 EN5
21 EN6
20 RT
38 37 36 35 34 33 32
FB1 1
V
IN1
2
SW1 3
SW2 4
V
IN2
5
FB2 6
FB3 7
V
IN3
8
SW3 9
SW4 10
V
IN4
11
FB4 12
FB3 10
V
IN3
11
SW3 12
SW4 13
V
IN4
14
FB4 15
EN4 16
EN3 17
PGOOD_ALL 18
SYNC 19
UHF PACKAGE
38-LEAD (5mm
×
7mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
FE PACKAGE
38-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 25°C/W
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
http://www.linear.com/product/LTC3374A#orderinfo
LEAD FREE FINISH
LTC3374AEUHF#PBF
LTC3374AIUHF #PBF
LTC3374AHUHF #PBF
LTC3374AEFE #PBF
LTC3374AIFE #PBF
LTC3374AHFE #PBF
TAPE AND REEL
LTC3374AEUHF#TRPBF
LTC3374AIUHF#TRPBF
LTC3374AHUHF#TRPBF
LTC3374AEFE#TRPBF
LTC3374AIFE#TRPBF
LTC3374AHFE#TRPBF
PART MARKING*
3374A
3374A
3374A
LTC3374AFE
LTC3374AFE
LTC3374AFE
PACKAGE DESCRIPTION
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead Plastic TSSOP
38-Lead Plastic TSSOP
38-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–40°C to 125°C
–40°C to 125°C
–40°C to 150°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.
2
3374af
For more information
www.linear.com/LTC3374A
LTC3374A
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
CC
= V
IN1-8
= 3.3V, unless otherwise specified.
SYMBOL PARAMETER
V
CC
V
CC
Voltage Range
Undervoltage Lockout (UVLO)
Threshold on V
CC
I
CC
V
CC
Input Supply Current
V
CC
Voltage Falling
V
CC
Voltage Rising
All Switching Regulators in Shutdown
One or More Bucks Active
SYNC = 0V, All Enabled Bucks Sleeping
One Buck Enabled, Not Sleeping, SYNC = 0V
All Bucks Enabled, Not Sleeping, SYNC = 2MHz
f
OSC
Internal Oscillator Frequency
V
RT
= V
CC
, SYNC = 0V
V
RT
= V
CC
, SYNC = 0V
R
T
= 400k, SYNC = 0V
t
LOW
, t
HIGH
> 40ns
l
l
l
l
l
elecTrical characTerisTics
CONDITIONS
MIN
l
l
l
TYP
2.45
2.55
0
45
155
200
MAX
5.5
2.55
2.65
1
75
230
300
2.1
2.25
2.15
3
0.4
UNITS
V
V
V
µA
µA
µA
µA
MHz
MHz
MHz
MHz
V
V
mV
V
V
V
V
µA
µA
µA
µA
A
A
A
A
mV
mV
mV
nA
%
mΩ
mΩ
mΩ
mΩ
2.7
2.35
2.45
1.9
1.75
1.85
1
1.2
780
2.25
1.95
2.05
V
FB
2
2
2
Synchronization Frequency
V
SYNC
V
RT
V
IN
SYNC Level High
SYNC Level Low
RT Servo Voltage
Buck Input Voltage Range
Undervoltage Lockout (UVLO)
Threshold on V
IN
V
OUT
I
VIN
Buck Output Voltage Range
Shutdown Input Current
Burst Mode
®
Operation
Burst Mode Operation
Forced Continuous Mode Operation
PMOS Current Limit
R
T
= 400k
l
800
820
5.5
1A Buck Regulators
l
V
IN
Voltage Falling
V
IN
Voltage Rising
l
l
l
2.05
2.15
0
20.5
400
400
2.15
2.25
V
IN
2
35
550
550
2.2
Buck in Regulation, Sleeping
Buck in Regulation, Not Sleeping, I
SW
= 0µA (Note 4)
I
SW
= 0µA, V
FB
= 0V (Note 4)
1 Buck Converter (Note 5)
2 Buck Converters Combined (Note 5)
3 Buck Converters Combined (Note 5)
4 Buck Converters Combined (Note 5)
Buck 1
Buck 1
Bucks 2 to 8
V
FB
= 0V
I
SW
= 100mA, V
IN
= 5.0V
I
SW
= 100mA, V
IN
= 3.3V
I
SW
= 100mA, V
IN
= 5.0V
I
SW
= 100mA, V
IN
= 3.3V
EN = 0
EN = 0
(Note 6)
Buck 1, as a Percentage of the Regulated V
OUT
Bucks 2 to 8, as a Percentage of the Regulated V
OUT
As a Percentage of the Regulated V
OUT
As a Percentage of the Regulated V
OUT
As a Percentage of the Regulated V
OUT
l
l
l
l
l
l
I
LIM
1.4
1.8
3.6
5.4
7.2
800
800
800
0
205
245
125
135
V
FB1
V
FB2-8
Feedback Regulation Voltage
Feedback Regulation Voltage
Feedback Pin Leakage Current
Maximum Duty Cycle
796
792
784
–50
100
804
808
816
50
l
R
PMOS
R
NMOS
PMOS On-Resistance
NMOS On-Resistance
PMOS Leakage Current
NMOS Leakage Current
Soft-Start Time
Rising PGOOD Threshold Voltage
PGOOD Hysteresis
Overvoltage Indication
Overvoltage Hysteresis
–100
–100
0.25
97
94
0.5
106
2
0
0
1.3
98
95
1
107.5
3
100
100
3
99
96
1.5
109
4
nA
nA
ms
%
%
%
%
%
3374af
For more information
www.linear.com/LTC3374A
3
LTC3374A
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
CC
= V
IN1-8
= 3.3V, unless otherwise specified.
SYMBOL PARAMETER
Temperature Monitor
V
TEMP
OT
TEMP Voltage at 25°C
V
TEMP
Slope
Overtemperature Shutdown (Note 3)
Temperature Rising
Hysteresis
5.5V at the PGOOD_ALL Pin
3mA into the PGOOD_ALL Pin
MODE Pin
MODE Pin
MODE, EN
1-8
MODE, EN
1-8
First Regulator Turning On
One Regulator Already in Use
l
l
l
l
l
elecTrical characTerisTics
CONDITIONS
MIN
200
TYP
220
7
170
10
MAX
240
UNITS
mV
mV/°C
°C
°C
Interface Logic Pins
I
OH
V
OL
V
IH
V
IL
I
IH
I
IL
Output High Leakage Current
Output Low Voltage
Input High Threshold
Input Low Threshold
Input High Leakage Current
Input Low Leakage Current
EN Rising Threshold
EN Falling Threshold
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 LTC3374A is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3374AE is guaranteed to meet specifications from
0°C to 85°C 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
LTC3374AI is guaranteed over the –40°C to 125°C operating junction
temperature range and the LTC3374AH is guaranteed over the –40°C to
150°C operating junction temperature range. High junction temperatures
degrade operating lifetimes; operating lifetime is derated for junction
temperatures greater than 125°C. Note that the maximum ambient
temperature consistent with these specifications is determined by specific
operating conditions in conjunction with board layout, the rated package
thermal impedance, and other environmental factors. The junction
temperature (T
J
in °C) is calculated from ambient temperature (T
A
in °C)
and power dissipation (P
D
in Watts) according to the formula:
T
J
= T
A
+ (P
D
•
θ
JA
)
where
θ
JA
(in °C/W) is the package thermal impedance.
–1
1.2
0.4
–100
–100
400
380
300
0
0
730
400
320
100
100
1200
420
340
0
0.1
1
0.4
µA
V
V
V
nA
nA
mV
mV
mV
Note 3:
The LTC3374A includes overtemperature protection which
protects the device during momentary overload conditions. Junction
temperatures will exceed 150°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may impair device reliability.
Note 4:
Static current, switches not switching. Actual current may be
higher due to gate charge losses at the switching frequency.
Note 5:
The current limit features of this part are intended to protect the
IC from short term or intermittent fault conditions. Continuous operation
above the maximum specified pin current rating may result in device
degradation over time.
Note 6:
The Soft-Start Time is the time from the start of switching until the
FB pin reaches 775mV. When a buck is enabled there is a 100μs (typical)
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