BOOST1, BOOST2 Voltages ....................... –0.3V to 46V
SW1, SW2 Voltages ...................................... –5V to 40V
INTV
CC
, DRV
CC1
, DRV
CC2
, EXTV
CC
, PGOOD, RUN,
(BOOST1-SW1), (BOOST2-SW2), MODE/PLLIN
Voltages ....................................................... –0.3V to 6V
V
OUTSENSE1+
, V
OUTSENSE1–
, SENSE1
+
, SENSE1
–
,
SENSE2
+
, SENSE2
–
Voltages ....................... –0.6V to 6V
TRACK/SS1 Voltage ..................................... –0.3V to 5V
DTR1, CVCC, PHASMD, RT, V
RNG1
, V
RNG2
, VTTSNS,
VDDQSNS, VTTR, ITH1, ITH2
Voltages ................................ ..–0.3V to (INTV
CC
+ 0.3V)
Operating Junction Temperature Range
(Notes 2, 3, 4) ....................................... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
FE Package ...................................................... 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
PHASMD
SENSE2
+
SENSE2
–
BOOST2
VTTSNS
V
RNG2
CVCC
CVCC
SENSE2
–
SENSE2
+
PHASMD
31 TG2
30 SW2
29 BG2
28 DRV
CC2
27 EXTV
CC
PGND
39
26 INTV
CC
25 PGND
24 V
IN
23 DRV
CC1
22 BG1
21 SW1
20 TG1
13 14 15 16 17 18 19
RUN
V
OUTSENSE1–
SENSE1
+
SENSE1
–
PGOOD
DTR1
BOOST1
ITH2
VDDQSNS
VTTR
VTTRVCC
MODE/PLLIN
1
2
3
4
5
6
7
8
9
PGND
39
38 V
RNG2
37 VTTSNS
36 BOOST
35 TG2
34 SW2
33 BG2
32 DRV
CC
31 EXTV
CC
30 INTV
CC
29 PGND
28 V
IN
27 DRV
CC1
26 BG1
25 SW1
24 TG1
23 BOOST1
22 PGOOD
21 RUN
20 DTR1
38 37 36 35 34 33 32
ITH2 1
VDDQSNS 2
VTTR 3
VTTRVCC 4
MODE/PLLIN 5
CLKOUT 6
SGND 7
RT 8
V
RNG1
9
ITH1 10
TRACK/SS1 11
V
OUTSENSE1+
12
CLKOUT 10
SGND 11
RT 12
V
RNG1
13
ITH1 14
TRACK/SS1 15
V
OUTSENSE1+
16
V
OUTSENSE1–
17
SENSE1
+
18
SENSE1
–
19
UHF PACKAGE
38-LEAD (5mm × 7mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB PGND
FE PACKAGE
38-LEAD PLASTIC TSSOP
T
JMAX
= 125°C,
θ
JA
= 28°C/W
EXPOSED PAD (PIN 39) IS PGND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3876EUHF#PBF
LTC3876IUHF#PBF
LTC3876EFE#PBF
LTC3876IFE#PBF
TAPE AND REEL
LTC3876EUHF#TRPBF
LTC3876IUHF#TRPBF
LTC3876EFE#TRPBF
LTC3876IFE#TRPBF
PART MARKING*
3876
3876
LTC3876FE
LTC3876FE
PACKAGE DESCRIPTION
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead Plastic TSSOP
38-Lead Plastic TSSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–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.
Consult LTC Marketing for information on non-standard lead based finish parts.
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/
3876f
2
LTC3876
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
VDDQ(REG)
VTTR(REG)
VTTSNS(REG)
I
Q
PARAMETER
Input Voltage Operating Range
VDDQ Regulated Operating Range
VTTR Regulated Operating Range
VTTSNS Regulated Operating Range
Input DC Supply Current
Both Channels Enabled
Shutdown Supply Current
VDDQ Regulates Differentially with Respect
to V
OUTSENSE1–
, VTTSNS and VTTR Regulate
Differentially to One-Half VDDQ with Respect to
V
OUSTSENSE1–
MODE/PLLIN = 0V, No Load
RUN1 = RUN2 = 0V
0.5985
0.596
0.594
Main Control Loop
4.5
1.0
0.5
0.5
38
2.5
1.25
1.25
V
V
V
V
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted. (Note 3)
CONDITIONS
MIN
TYP
MAX
UNITS
5000
20
0.6015
0.604
0.606
μA
μA
V
V
V
V
DFB1(REG)
Regulated Differential Feedback Voltage on ITH1 = 1.2V (Note 5)
Channel 1, VDDQ
T
A
= 25°C
(V
OUTSENSE1+
– V
OUTSENSE1–
)
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
Regulated Differential Feedback Voltage
on Channel 1, VDDQ Over Line, Load and
Common Mode
V
IN
= 4.5V to 38V, ITH1 = 0.5V to 1.9V,
V
OUTSENSE1–
= ±500mV (Notes 5, 7)
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
ITH2 = 1.4V (Note 5)
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
V
IN
= 4.5V to 38V, ITH1 = 0.5V to 1.9V,
(Notes 5, 7)
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
V
DFB1
[V
OUTSENSE1+
– V
OUTSENSE1–
] = 0.6V
V
DFB1
[V
OUTSENSE1+
– V
OUTSENSE1–
] = 0.6V
I
VTTSNS
= 750mV
ITH = 1.2V (Note 3)
V
IN
= 38V, R
T
= 20k, VDDSNS = 1.2V, V
SENSE–
= 0.6V
l
l
0.6
0.6
l
l
l
l
0.594
0.591
–10
–15
0.6
0.6
0.606
0.609
10
15
V
V
mV
mV
VTTSNS(REG)
Regulated Voltage Error on Channel 2,
VTTSNS (Referenced to VTTR)
Regulated Voltage Error on Channel 2,
VTTSNS Over Line, Load and Common
Mode. (Referenced to VTTR)
l
l
–15
–20
±5
–25
±5
1.7
30
90
15
20
±25
–50
±50
mV
mV
nA
μA
nA
mS
ns
ns
I
VOUTSENSE1+
I
VOUTSENSE1–
I
VTTSNS
g
m(EA)1,2
t
ON(MIN)1,2
t
OFF(MIN)1,2
Current Sensing
V
SENSE1(MAX)
V
OUTSENSE1+
Input Bias Current
V
OUTSENSE1–
Input Bias Current
I
VTTSNS
Input Bias Current
Error Amplifier Transconductance
Minimum On-Time
Minimum Off-Time
Maximum Valley Current Sense Threshold V
RNG
= 2V, V
DFB1
= 0.57V, V
SENSE1–
= 1.5V
(V
SENSE1+
– V
SENSE1–
)
V
RNG
= 0V, V
DFB1
= 0.57V, V
SENSE1–
= 1.5V
V
RNG
= INTV
CC
, V
DFB1
= 0.57V, V
SENSE1–
= 1.5V
Minimum Valley Current Sense Threshold
(V
SENSE1+
– V
SENSE1–
)
(Forced Continuous Mode)
V
RNG
= 2V, V
DFB1
= 0.63V, V
SENSE1–
= 1.5V
V
RNG
= 0V, V
DFB1
= 0.63V, V
SENSE1–
= 1.5V
V
RNG
= INTV
CC
, V
DFB1
= 0.63V, V
SENSE1–
= 1.5V
l
l
l
80
21
39
100
30
50
–50
–15
–25
120
40
61
mV
mV
mV
mV
mV
mV
V
SENSE1(MIN)
V
SENSE2(MAX)
Maximum Valley Current Sense Threshold V
RNG
= 2V, VTTSNS = 0.72V, V
SENSE2–
= 0.75V
(V
SENSE2+
– V
SENSE2–
)
V
RNG
= 0V, VTTSNS = 0.72V, V
SENSE2–
= 0.75V
V
RNG
= INTV
CC
, VTTSNS = 0.72V, V
SENSE2–
= 0.75V
Minimum Valley Current Sense Threshold
(V
SENSE1+
– V
SENSE1–
)
(Forced Continuous Mode)
SENSE1,2
+
Pins Input Bias Current
SENSE2
–
Pins Input Bias Current
(Internal 500k Resistor to SGND)
V
RNG
= 2V, VTTSNS = 0.78V, V
SENSE2–
= 0.75V
V
RNG
= 0V, VTTSNS = 0.78V, V
SENSE2–
= 0.75V
V
RNG
= INTV
CC
, VTTSNS = 0.78V, V
SENSE2–
= 0.75V
V
SENSE+
= 0.6V
V
SENSE+
= 2.5V
V
SENSE1–
= 0.6V
V
SENSE1–
= 2.5V
l
l
l
80
21
39
100
30
50
–120
–36
–60
±5
1
1.2
5
120
40
61
mV
mV
mV
mV
mV
mV
V
SENSE2(MIN)
I
SENSE1,2+
I
SENSE1,2–
±50
±2
nA
μA
μA
μA
3876f
3
LTC3876
ELECTRICAL CHARACTERISTICS
SYMBOL
V
RUN(TH)
V
RUN(HYS)
I
RUN(OFF)
I
RUN(HYS)
V
UVLO(INTVCC)
I
TRACK/SS
f
CLKOUT
φ
VTT
φ
CLKOUT
PARAMETER
RUN Pin On Threshold
RUN Pin On Hysteresis
RUN Pin Pull-Up Current When Off
RUN Pin Pull-Up Current Hysteresis
INTV
CC
Undervoltage Lockout
Soft-Start Pull-Up Current
Clock Output Frequency
(Steady-State Switching Frequency)
VTT Channel 2 Phase
(Relative to Channel 1)
CLKOUT Phase
(Relative to Channel 1)
Clock Output Voltage High
Clock Output Voltage Low
Clock Input Voltage High
Clock Input Voltage Low
MODE/PLLIN Input DC Resistance
TG Driver Pull-Up On-Resistance
TG Driver Pull-Down On-Resistance
BG Driver 1 Pull-Up On-Resistance
BG Driver 2 Pull-Up On-Resistance
BG Driver Pull-Down On-Resistance
TG High
TG Low
BG1 High
BG2 High
BG Low
Start-Up and Shutdown
V
RUN
Rising
V
RUN
Falling from V
RUN(TH)
RUN = SGND
I
RUN(HYS)
= I
RUN(ON)
– I
RUN(OFF)
INTV
CC
Falling
INTV
CC
Rising
0V < TRACK/SS < 0.6V
R
T
= 205k
R
T
= 80.6k
R
T
= 18.2k
V
PHASMD
= SGND
V
PHASMD
= Floating
V
PHASMD
= INTV
CC
V
PHASMD
= SGND
V
PHASMD
= Floating
V
PHASMD
= INTV
CC
Pulling to INTV
CC
Pulling to SGND
f
MODE/PLLIN
>100kHz
f
MODE/PLLIN
>100kHz
600
2.5
1.2
2.5
1.6
0.8
20
15
0
2
–0.5
l
l
l
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted. (Note 3)
CONDITIONS
MIN
1.15
TYP
1.2
100
2.5
10
3.3
3.7
4.2
1
200
500
2000
180
180
240
60
90
120
V
INTVCC
4.5
MAX
1.25
UNITS
V
mV
μA
μA
V
V
μA
kHz
kHz
kHz
Deg
Deg
Deg
Deg
Deg
Deg
V
V
V
V
kΩ
Ω
Ω
Ω
Ω
Ω
ns
ns
Frequency and Clock Synchronization
450
550
V
CLKOUT(H)
V
CLKOUT(L)
V
PLLIN(H)
V
PLLIN(L)
R
MODE/PLLIN
Gate Drivers
R
TG(UP)1,2
R
TG(DOWN)1,2
R
BG(UP)1
R
BG(UP)2
R
BG(DOWN)1,2
T
D(TG/BG)1,2
T
D(BG/TG)1,2
VTT Reference
VTTR(I
VTTR
)
Top Gate Off to Bottom Gate On Delay Time (Note 6)
Bottom Gate Off to Top Gate On Delay Time (Note 6)
VTTR Load Regulation
–50mA < I
VTTR
< 50mA; T
A
= –40°C to 125°C
(VTTR(I
VTTR
) is Measured Through an
1.5 < VDDQ < 2.5
1.0 < VDDQ < 1.5
Internal Kelvin Connection to the VTTR Pin
and is Specified as the Ratio (VTTR(I
VTTR
)/
VDDQ)
Internal Regulated DRV
CC1
Voltage
DRV
CC1
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Switchover Hysteresis
EXTV
CC
to DRV
CC2
Voltage Drop
V
EXTVCC
= 5V, I
DRVCC2
= 100mA
6V < V
IN
< 38V
I
CC
= 0mA to 100mA
EXTV
CC
Rising
4.4
l
l
0.4940
0.4930
0.5060
0.5070
V/V
V/V
Internal V
CC
Regulator
V
DRVCC1
∆V
DRVCC1
V
EXTVCC(TH)
V
EXTVCC(HYS)
∆V
DRVCC2
5.0
5.3
–1.5
4.6
200
200
5.6
–3
4.8
V
%
V
mV
mV
3876f
4
LTC3876
ELECTRICAL CHARACTERISTICS
SYMBOL
PGood Output
PGD
OV
PGD
UV
PGD
HYS
V
PGD(LO)
t
PGD(FALL)
t
PGD(RISE)
PGOOD Overvoltage Threshold
PGOOD Undervoltage Threshold
PGOOD Threshold Hysteresis
PGOOD Low Voltage
Delay from OV/UV Fault to PGOOD Falling
Delay from OV/UV Recovery to PGOOD
Rising
V
OUTSENSE
, VTTSNS Rising, with Respect to
Reference Voltage
V
OUTSENSE
, VTTSNS Falling, with Respect to
Reference Voltage
V
OUTSENSE
, VTTSNS Returning to Reference
Voltage
I
PGOOD
= 2mA
5
–5
7.5
–7.5
2.0
0.1
50
20
0.3
10
–10
%
%
%
V
μs
μs
PARAMETER
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V unless otherwise noted. (Note 3)
CONDITIONS
MIN
TYP
MAX
UNITS
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:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC3876UHF: T
J
= T
A
+ (P
D
• 34°C/W)
LTC3876FE: T
J
= T
A
+ (P
D
• 28°C/W)
Note 3:
The LTC3876 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3876E is guaranteed to meet performance specifications
from 0°C to 85°C. Specifications over the –40°C to 125°C operating
junction temperature range are assured by design, characterization
and correlation with statistical process controls. The LTC3876I 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 specific
operating conditions in conjunction with board layout, the package thermal
impedance and other environmental factors.
Note 4:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair the device reliability or permanently
damage the device.
Note 5:
The LTC3876 is tested in a feedback loop that adjusts
(V
OUTSENSE1+
V
OUTSENSE1–
) and VTTSNS to achieve specified error
amplifier output voltages (ITH1,2).
Note 6:
Delay times are measured using 50% levels.
Note 7:
In order to simplify the total system error computation, the
regulated voltage is defined in one combined specification which includes
the effects of line, load and common mode variation. The combined
regulated voltage specification is tested by independently varying line,
load, and common mode, which by design do not significantly affect one
another. For any combination of line, load, and common mode variation,
the regulated voltage should be within the limits specified that are tested in
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