EXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCB
UFD PACKAGE
28-LEAD (4mm 5mm) PLASTIC QFN
GN PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 125°C, θ
JA
= 90°C/W
orDer inForMaTion
LEAD FREE FINISH
LTC3858EUFD-1#PBF
LTC3858IUFD-1#PBF
LTC3858EGN-1#PBF
LTC3858IGN-1#PBF
TAPE AND REEL
LTC3858EUFD-1#TRPBF
LTC3858IUFD-1#TRPBF
LTC3858EGN-1#TRPBF
LTC3858IGN-1#TRPBF
PART MARKING*
38581
38581
LTC3858GN-1
LTC3858GN-1
PACKAGE DESCRIPTION
28-Lead (4mm × 5mm) Plastic QFN
28-Lead (4mm × 5mm) Plastic QFN
28-Lead Plastic SSOP
28-Lead Plastic SSOP
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/
38581fb
LTC3858-1
elecTrical characTerisTics
SYMBOL
V
IN
V
FB1,2
I
FB1,2
V
REFLNREG
V
LOADREG
PARAMETER
Input Supply Operating Voltage Range
Regulated Feedback Voltage
(Note 4) I
TH1,2
= 1.2V
–40°C to 125°C
–40°C to 85°C
(Note 4)
(Note 4) V
IN
= 4.5V to 38V
(Note4)
Measured in Servo Loop,
∆I
TH
Voltage = 1.2V to 0.7V
(Note4)
Measured in Servo Loop,
∆I
TH
Voltage = 1.2V to 2V
g
m1,2
I
Q
Transconductance Amplifier g
m
Input DC Supply Current
Pulse Skip or Forced Continuous Mode
(One Channel On)
Pulse Skip or Forced Continuous Mode
(Both Channels On)
Sleep Mode (One Channel On)
(Note 4) I
TH1,2
= 1.2V, Sink/Source = 5µA
(Note 5)
RUN1 = 5V and RUN2 = 0V or
RUN1 = 0V and RUN2 = 5V,
V
FB1
= 0.83V (No Load)
RUN1,2 = 5V, V
FB1,2
= 0.83V (No Load)
RUN1 = 5V and RUN2 = 0V or
RUN1 = 0V and RUN2 = 5V,
V
FB1
= 0.83V (No Load)
RUN1,2 = 5V, V
FB1,2
= 0.83V (No Load)
RUN1,2 = 0V
INTV
CC
Ramping Up
INTV
CC
Ramping Down
Measured at V
FB1,2
, Relative to Regulated V
FB1,2
Each Channel
Each Channel
V
OUT1,2
< INTV
CC
– 0.5
V
OUT1,2
> INTVCC + 0.5
In Dropout, FREQ = 0V
V
SS1,2
= 0V
V
RUN1
, V
RUN2
Rising
V
SS1
, V
SS2
Rising from 1V
V
SS1
, V
SS2
Rising from 2V
Short-Circuit Condition V
FB1,2
= 0.5V
V
SS1,2
= 4.5V
V
FB1,2
= 0.7V, V
SENSE1
–,
2
– = 3.3V
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
CONDITIONS
MIN
4
0.788
0.792
0.800
0.800
±5
0.002
0.01
–0.01
2
1.3
2
170
300
8
3.6
7
4.0
3.8
10
540
98
0.7
1.23
1.9
1.3
7
43
99.4
1.0
1.28
50
2
1.5
10
50
2.1
1.7
13
57
1.4
1.33
250
450
20
4.2
4.0
13
±1
±1
700
TYP
MAX
38
0.812
0.808
±50
0.02
0.1
–0.1
UNITS
V
V
V
nA
%/V
%
%
mmho
mA
mA
µA
µA
µA
V
V
%
µA
µA
µA
%
µA
V
mV
V
V
µA
mV
Feedback Current
Reference Voltage Line Regulation
Output Voltage Load Regulation
l
Sleep Mode (Both Channels On)
Shutdown
UVLO
V
OVL
Undervoltage Lockout
Feedback Overvoltage Protection
SENSE
+
Pin Current
SENSE
–
Pins Current
I
SENSE+
I
SENSE–
DF
MAX
I
SS1,2
V
RUN1,2
On
V
SS1,2
LA
V
SS1,2
LT
I
DSC1,2
LT
V
SENSE(MAX)
Gate Driver
TG1,2
BG1,2
Maximum Duty Factor
Soft-Start Charge Current
RUN Pin On Threshold Voltage
SS Pin Latch-Off Arming Threshold
Voltage
SS Pin Latch-Off Threshold Voltage
SS Discharge Current
Maximum Current Sense Threshold
Voltage
Pull-Up On-Resistance
Pull-Down On-Resistance
Pull-Up On-Resistance
Pull-Down On-Resistance
V
RUN1,2
Hyst RUN Pin Hysteresis Voltage
2.5
1.5
2.4
1.1
Ω
Ω
Ω
Ω
38581fb
LTC3858-1
elecTrical characTerisTics
SYMBOL
TG1,2 t
r
TG1,2 t
f
BG1,2 t
r
BG1,2 t
f
TG/BG t
1D
BG/TG t
1D
t
ON(MIN)
V
INTVCCVIN
V
LDOVIN
V
INTVCCEXT
V
LDOEXT
V
EXTVCC
V
LDOHYS
f
25kΩ
f
65kΩ
f
105kΩ
f
LOW
f
HIGH
f
SYNC
V
PGL
I
PGOOD
V
PG
PARAMETER
TG Transistion Time:
Rise Time
Fall Time
BG Transistion Time:
Rise Time
Fall Time
Top Gate Off to Bottom Gate On Delay
Synchronous Switch-On Delay Time
Bottom Gate Off to Top Gate On Delay
Top Switch-On Delay Time
Minimum On-Time
Internal V
CC
Voltage
INTV
CC
Load Regulation
Internal V
CC
Voltage
INTV
CC
Load Regulation
EXTV
CC
Switchover Voltage
EXTV
CC
Hysteresis Voltage
Programmable Frequency
Programmable Frequency
Programmable Frequency
Low Fixed Frequency
High Fixed Frequency
Synchronizable Frequency
PGOOD1 Voltage Low
PGOOD1 Leakage Current
PGOOD1 Trip Level
R
FREQ
= 25k, PLLIN/MODE = DC Voltage
R
FREQ
= 65k, PLLIN/MODE = DC Voltage
R
FREQ
= 105k, PLLIN/MODE = DC Voltage
V
FREQ
= 0V, PLLIN/MODE = DC Voltage
V
FREQ
= INTV
CC
, PLLIN/MODE = DC Voltage
PLLIN/MODE = External Clock
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Negative
Hysteresis
V
FB
with Respect to Set Regulated Voltage
V
FB
Ramping Positive
Hysteresis
t
PG
Delay for Reporting a Fault (PGOOD Low)
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Ratings for extended periods may affect device reliability and
lifetime.
Note 2: The LTC3858E-1 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 LTC3858I-1 is guaranteed
over the full –40°C to 125°C operating junction temperature range.
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
T
J
= T
A
+ (P
D
• θ
JA
)
where θ
JA
= 43°C/W for the QFN package and θ
JA
= 90°C/W for the SSOP
package.
–13
7
–10
2.5
10
2.5
25
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 12V, V
RUN1,2
= 5V, EXTV
CC
= 0V unless otherwise noted.
CONDITIONS
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
C
LOAD
= 3300pF Each Driver
C
LOAD
= 3300pF Each Driver
(Note 7)
6V < V
IN
< 38V, V
EXTVCC
= 0V
I
CC
= 0mA to 50mA, V
EXTVCC
= 0V
6V < V
EXTVCC
< 13V
I
CC
= 0mA to 50mA, V
EXTVCC
= 8.5V
EXTV
CC
Ramping Positive
4.5
4.85
4.85
MIN
TYP
25
16
28
13
30
30
95
5.1
0.7
5.1
0.6
4.7
250
105
375
320
485
75
0.2
440
835
350
535
380
585
850
0.4
±1
–7
13
505
5.35
1.1
5.35
1.1
4.9
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
V
%
V
%
V
mV
kHz
kHz
kHz
kHz
kHz
kHz
V
µA
%
%
%
%
µs
INTV
CC
Linear Regulator
Oscillator and Phase-Locked Loop
PGOOD1 Output
Note 4: The LTC3858-1 is tested in a feedback loop that servos V
ITH1,2
to
a specified voltage and measures the resultant V
FB1,2
. The specification at
85°C is not tested in production. This specification is assured by design,
characterization and correlation to production testing at 125°C.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications information.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels
Note 7: The minimum on-time condition is specified for an inductor peak-
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