LT3467AES6#TRMPBF Linear Technology, LT3467AES6#TRMPBF Datasheet - Page 10

• Manufacturer Part Number: LT3467AES6#TRMPBF
• Description: IC CONV DC/DC STEP-UP TSOT23-6
• Manufacturer: Linear Technology
• Type: Step-Up (Boost)r

Specifications of LT3467AES6#TRMPBF

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.26 ~ 40 V
• Current - Output: 1.1A
• Frequency - Switching: 2.1MHz
• Voltage - Input: 2.4 ~ 16 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-6, TSOT-6
• Primary Input Voltage: 16V
• No. Of Outputs: 1
• Output Voltage: 40V
• Output Current: 1.1A
• No. Of Pins: 6
• Operating Temperature Range: -40°C To +85°C
• Msl: MSL 1 - Unlimited
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: LT3467AES6#PBF; LT3467AES6#PBF; LT3467AES6#TRMPBF; LT3467AES6#TRMPBFTR

APPLICATIONS INFORMATION
LT3467/LT3467A
Compensation—Theory
Like all other current mode switching regulators, the
LT3467/LT3467A needs to be compensated for stable
and effi cient operation. Two feedback loops are used in
the LT3467/LT3467A: a fast current loop which does not
require compensation, and a slower voltage loop which
does. Standard Bode plot analysis can be used to under-
stand and adjust the voltage feedback loop.
As with any feedback loop, identifying the gain and phase
contribution of the various elements in the loop is critical.
Figure 6 shows the key equivalent elements of a boost
converter. Because of the fast current control loop, the
power stage of the IC, inductor and diode have been re-
placed by the equivalent transconductance amplifi er g
g
proportional to the V
output current of gmp is fi nite due to the current limit
in the IC.
10
mp
R
V
acts as a current source where the output current is
C
C
C
C
C
C
g
g
R
R
R
R1, R2: FEEDBACK RESISTOR DIVIDER NETWORK
R
C
ma
mp
C
OUT
PL
C
L
O
ESR
: COMPENSATION CAPACITOR
: COMPENSATION RESISTOR
: OUTPUT RESISTANCE DEFINED AS V
: OUTPUT RESISTANCE OF g
: PHASE LEAD CAPACITOR
: TRANSCONDUCTANCE AMPLIFIER INSIDE IC
: POWER STAGE TRANSCONDUCTANCE AMPLIFIER
R
: OUTPUT CAPACITOR
: OUTPUT CAPACITOR ESR
O
Figure 6. Boost Converter Equivalent Model
–
+
g
mp
g
ma
+
–
C
voltage. Note that the maximum
ma
REFERENCE
1.255V
OUT
C
PL
DIVIDED BY I
3467 F06
R1
R2
LOAD(MAX)
R
ESR
C
OUT
R
L
V
OUT
mp
.
From Figure 6, the DC gain, poles and zeroes can be
calculated as follows:
The current mode zero is a right-half plane zero which can
be an issue in feedback control design, but is manageable
with proper external component selection.
Output Pole: P1=
Error Amp Pole: P2=
Error Amp Zero: Z1=
DC GAIN: A=
ESR Zero: Z2 =
RHP Zero: Z3=
High Frequency Pole: P3>
Phase Lead Zero: Z4 =
Phase Lead Pole: P4 =
V
1.255
OUT
2 • π • V
2 • π • R
2 • π • R
2
V
IN
• V
2 • π • R
2 • π • R
2
2 • π • C
IN
OUT
2 • π • R1• C
ESR
• R
1
2
• g
L
L
2
f
3
• C
S
1
1
ma
• C
• L
O
C
1
OUT
PL
OUT
• C
• C
• R
1
•
C
C
O
R1+ R2
PL
R1• R2
• g
mp
• R
L
•
2
1
3467afe