Datasheet

LTC3876
3
3876f
ELECTRICAL CHARACTERISTICS
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)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Main Control Loop
V
IN
Input Voltage Operating Range 4.5 38 V
VDDQ(REG)
VTTR(REG)
VTTSNS(REG)
VDDQ Regulated Operating Range
VTTR Regulated Operating Range
VTTSNS Regulated Operating Range
VDDQ Regulates Differentially with Respect
to V
OUTSENSE1
–
, VTTSNS and VTTR Regulate
Differentially to One-Half VDDQ with Respect to
V
OUSTSENSE1
–
1.0
0.5
0.5
2.5
1.25
1.25
V
V
V
I
Q
Input DC Supply Current
Both Channels Enabled
Shutdown Supply Current
MODE/PLLIN = 0V, No Load
RUN1 = RUN2 = 0V
5000
20
µA
µA
V
DFB1(REG)
Regulated Differential Feedback Voltage on
Channel 1, VDDQ
(V
OUTSENSE1
+
– V
OUTSENSE1
–
)
ITH1 = 1.2V (Note 5)
T
A
= 25°C
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
l
l
0.5985
0.596
0.594
0.6
0.6
0.6015
0.604
0.606
V
V
V
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
l
l
0.594
0.591
0.6
0.6
0.606
0.609
V
V
VTTSNS(REG) Regulated Voltage Error on Channel 2,
VTTSNS (Referenced to VTTR)
ITH2 = 1.4V (Note 5)
T
A
= 0°C to 85°C
T
A
= –40°C to 125°C
l
l
–10
–15
10
15
mV
mV
Regulated Voltage Error on Channel 2,
VTTSNS Over Line, Load and Common
Mode. (Referenced to VTTR)
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
l
l
–15
–20
15
20
mV
mV
I
VOUTSENSE1
+
V
OUTSENSE1
+
Input Bias Current V
DFB1
[V
OUTSENSE1
+
– V
OUTSENSE1
–
] = 0.6V ±5 ±25 nA
I
VOUTSENSE1
–
V
OUTSENSE1
–
Input Bias Current V
DFB1
[V
OUTSENSE1
+
– V
OUTSENSE1
–
] = 0.6V –25 –50 µA
I
VTTSNS
I
VTTSNS
Input Bias Current I
VTTSNS
= 750mV ±5 ±50 nA
g
m(EA)1,2
Error Amplifier Transconductance ITH = 1.2V (Note 3) 1.7 mS
t
ON(MIN)1,2
Minimum On-Time V
IN
= 38V, R
T
= 20k, VDDSNS = 1.2V, V
SENSE
–
= 0.6V 30 ns
t
OFF(MIN)1,2
Minimum Off-Time 90 ns
Current Sensing
V
SENSE1(MAX)
Maximum Valley Current Sense Threshold
(V
SENSE1
+
– V
SENSE1
–
)
V
RNG
= 2V, V
DFB1
= 0.57V, V
SENSE1
–
= 1.5V
V
RNG
= 0V, V
DFB1
= 0.57V, V
SENSE1
–
= 1.5V
V
RNG
= INTV
CC
, V
DFB1
= 0.57V, V
SENSE1
–
= 1.5V
l
l
l
80
21
39
100
30
50
120
40
61
mV
mV
mV
V
SENSE1(MIN)
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
–50
–15
–25
mV
mV
mV
V
SENSE2(MAX)
Maximum Valley Current Sense Threshold
(V
SENSE2
+
– V
SENSE2
–
)
V
RNG
= 2V, VTTSNS = 0.72V, V
SENSE2
–
= 0.75V
V
RNG
= 0V, VTTSNS = 0.72V, V
SENSE2
–
= 0.75V
V
RNG
= INTV
CC
, VTTSNS = 0.72V, V
SENSE2
–
= 0.75V
l
l
l
80
21
39
100
30
50
120
40
61
mV
mV
mV
V
SENSE2(MIN)
Minimum Valley Current Sense Threshold
(V
SENSE1
+
– V
SENSE1
–
)
(Forced Continuous Mode)
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
–120
–36
–60
mV
mV
mV
I
SENSE1,2
+
SENSE1,2
+
Pins Input Bias Current V
SENSE
+
= 0.6V
V
SENSE
+
= 2.5V
±5
1
±50
±2
nA
µA
I
SENSE1,2
–
SENSE2
–
Pins Input Bias Current
(Internal 500k Resistor to SGND)
V
SENSE1
–
= 0.6V
V
SENSE1
–
= 2.5V
1.2
5
µA
µA