(Note 2) ................................................... –40°C to 85°C
Junction Temperature (Note 3) ............................. 125°C
Storage Temperature Range
SSOP ................................................. –65°C to 150°C
QFN.................................................... –65°C to 125°C
QFN Reflow Peak Body Temperature .................... 260°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
TOP VIEW
DPRSLPVR
V
FB
DPRSLPVR
FREQSET
PSIB
V
OA
+
TOP VIEW
MCH_PG
BOOST1
PGOOD
SW1
31 NC
30 BOOST2
29 TG2
28 SW2
27 PV
CC
39
26 BG1
25 PGND
24 BG2
23 VID5
22 VID4
21 VID3
20 VID2
VID1
TG1
VID0
1
2
3
4
5
6
7
8
9
36 MCH_PG
35 PGOOD
34 BOOST1
33 TG1
32 SW1
31 BOOST2
30 TG2
29 SW2
28 PV
CC
27 BG1
26 PGND
25 BG2
24 VID5
23 VID4
22 VID3
21 VID2
20 VID1
19 VID0
FREQSET 1
PSIB 2
V
OA+
3
V
OA–
4
OAOUT 5
STP_CPUB 6
SGND 7
SENSE1
+
38 37 36 35 34 33 32
V
OA–
OAOUT
STP_CPUB
SGND
SENSE1
+
10
SENSE1
–
11
SENSE2
+
12
SENSE2
–
13
RDPRSLP 14
RDPSLP 15
RUN/SS 16
I
TH
17
RBOOT 18
8
9
10
11
13 14 15 16 17 18 19
RDPSLP
RUN/SS
RBOOT
I
TH
NC
SENSE1
–
SENSE2
+
SENSE2
–
RDPRSLP 12
G PACKAGE
36-LEAD PLASTIC SSOP
UHF PACKAGE
38-LEAD (7mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 85°C/W
T
JMAX
= 125°C,
θ
JA
= 34°C/W
EXPOSED PAD (PIN 39) IS SIGNAL GROUND, MUST BE CONNECTED TO PCB AND SGND
ORDER INFORMATION
LEAD FREE FINISH
LTC3735EG#PBF
LTC3735EUHF#PBF
TAPE AND REEL
LTC3735EG#TRPBF
LTC3735EUHF#TRPBF
PART MARKING*
LTC3735
LTC3735
PACKAGE DESCRIPTION
36-Lead Plastic SSOP
38-Lead (7mm
×
5mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°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/
3735fa
2
V
FB
LTC3735
ELECTRICAL CHARACTERISTICS
SYMBOL
Reference
V
SENSEMAX
V
LOADREG
V
REFLNREG
V
PSIB
I
PSIB
V
OVL
g
m
g
mOL
V
ACTIVE
I
Q
UVR
I
RUN/SS
VRUN/SS
V
RUN/SSLO
I
SCL
I
SDLHO
I
SENSE
DF
MAX
TG1, 2 t
r
TG1, 2 t
f
BG1, 2 t
r
BG1, 2 t
f
TG/BG t
1D
BG/TG t
2D
t
ON(MIN)
R
ATTEN
ATTEN
ERR
VID
THLOW
VID
THHIGH
VID
LEAK
PARAMETER
Regulated Feedback Voltage
Maximum Current Sense Threshold
Output Voltage Load Regulation
Main Control Loop
I
TH
Voltage = 0.5V; Measured at V
FB
(Note 4)
I
TH
Voltage = Max; V
CM
= 1.7V
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
PVCC
= 5V, V
RUN/SS
= 5V unless otherwise noted.
CONDITIONS
MIN
TYP
0.600
59
72
0.1
–0.1
0.02
0.57
V
PSIB
= 0V
Measured with Respect to V
FB
= 0.6V
I
TH
= 1.2V, Sink/Source 25µA (Note 4)
I
TH
= 1.2V, (g
m
• Z
L
; No Ext Load) (Note 4)
VID = 010110, I
TH
= 0.5V (0°C to 85°C)
VID = 010110, I
TH
= 0.5V (Note 2)
(Note 5)
V
RUN/SS
= 0V
PV
CC
Lowered Until the RUN/SS Pin is Pulled Low
V
RUN/SS
= 1.9V
V
RUN/SS
Rising
V
RUN/SS
Rising from 3V
V
RUN/SS
, Ramping Negative
Soft-Short Condition V
FB
= 0.375V, V
RUN/SS
= 4.5V
V
FB
= 0.375V, V
RUN/SS
= 4.5V
Each Channel: V
SENSE1–, 2–
= V
SENSE1+, 2+
= 0V
In Dropout, V
SENSEMAX
≤ 45mV
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
(Note 6)
C
LOAD
= 3300pF
C
LOAD
= 3300pF
–85
95
–5
3.2
–2.3
1.0
l
l
MAX
UNITS
V
85
0.5
–0.5
0.1
0.63
–1
0.68
7.5
1.370
1.376
3
100
4.2
–0.8
1.9
mV
%
%
%/V
V
µA
V
mmho
V/mV
V
V
mA
µA
V
µA
V
V
V
µA
(Note 4)
Measured in Servo Loop, ∆I
TH
Voltage: 1.2V to 0.7V
l
l
Measured in Servo Loop, ∆I
TH
Voltage: 1.2V to 2V
V
PVCC
= 4.5V to 7V
Reference Voltage Line Regulation
Forced Continuous Threshold
Forced Continuous Current
Output Overvoltage Threshold
Transconductance Amplifier g
m
Transconductance Amplifier Gain
Output Voltage in Active Mode
Input DC Supply Current
Normal Mode
Shutdown
Undervoltage RUN/SS Reset
Soft-Start Charge Current
RUN/SS Pin ON Threshold
RUN/SS Pin Latchoff Threshold
RUN/SS Discharge Current
Shutdown Latch Disable Current
Total Sense Pins Source Current
Maximum Duty Factor
Top Gate Transition Time:
Rise Time
Fall Time
Bottom Gate Transition Time:
Rise Time
Fall Time
0.6
–0.5
0.66
6
3
1.356
1.356
2
20
3.7
–1.5
1.5
3.9
3.2
–1.5
1.5
–60
98.5
30
40
60
50
50
60
100
5.33
0.64
4.5
1.342
1.336
V
RUN/SSARM
RUN/SS Pin Latchoff Arming
5
µA
µA
%
90
90
90
90
ns
ns
ns
ns
ns
ns
ns
kΩ
Top Gate Off to Bottom Gate On Delay C
LOAD
= 3300pF Each Driver (Note 6)
Synchronous Switch-On Delay Time
Bottom Gate Off to Top Gate On Delay C
LOAD
= 3300pF Each Driver (Note 6)
Top Switch-On Delay Time
Minimum On-Time
VID Top Resistance
Resistive Divider Error
VID0 to VID5 Logic Threshold Low
VID0 to VID5 Logic Threshold High
VID0 to VID5 Leakage
0.7
(Note 8)
l
Tested with a Square Wave (Note 7)
VID Parameters
–0.25
0.25
0.3
±1
%
V
V
µA
3735fa
3
LTC3735
ELECTRICAL CHARACTERISTICS
SYMBOL
Oscillator
I
FREQSET
f
NOM
f
LOW
f
HIGH
V
PGL
I
PGOOD
V
PG
t
MASK
t
DELAY
I
B
V
OS
CM
CMRR
I
CL
A
VOL
GBP
SR
V
O(MAX)
FREQSET Input Current
Nominal Frequency
Lowest Frequency
Highest Frequency
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Thresholds
V
FREQSET
= 0V
V
FREQSET
= 1.2V
V
FREQSET
= 0V
V
FREQSET
≥ 2.4V
I
PGOOD
= 2mA
V
PGOOD
= 5V
V
FB
with Respect to Set Output Voltage
V
FB
Ramping Negative
V
FB
Ramping Positive
–7
7
100
–10
11
110
15
15
V
OA
+ = V
OA
– 1.2V, I
OUT
= 1mA
0
I
OUT
= 1mA
I
OUT
= 1mA
I
OUT
= 1mA
R
L
= 2k
I
OUT
= 1mA
46
10
70
35
30
2
5
P
VCC
– 1.2 P
VCC
– 0.9
0.8
200
5
P
VCC
– 1.4
320
190
490
–2
355
210
550
0.1
–1
390
240
610
0.3
±1
–13
13
120
µA
kHz
kHz
kHz
V
µA
%
%
µs
cycles
nA
mV
V
dB
mA
V/mV
MHz
V/µs
V
PARAMETER
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
PVCC
= 5V, V
RUN/SS
= 5V unless otherwise noted.
CONDITIONS
MIN
TYP
MAX
UNITS
PGOOD Output
PGOOD Mask Timer
MCH_PG Delay Time
Input Bias Current
Input Offset Voltage Magnitude
Common Mode Input Voltage Range
Common Mode Rejection Ratio
Output Source Current
Open-Loop DC Gain
Gain-Bandwidth Product
Slew Rate
Maximum High Output Voltage
Operational Amplifier
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 LTC3735E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the – 40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC3735EG: T
J
= T
A
+ (P
D
• 85°C/W)
LTC3735EUHF: T
J
= T
A
+ (P
D
• 34°C/W)
Note 4:
The LTC3735 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
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 corresponds to the on inductor
peak-to-peak ripple current
≥40%
I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
Note 8:
The ATTEN
ERR
specification is in addition to the output voltage
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