LT3463EDD#TRPBF Linear Technology, LT3463EDD#TRPBF Datasheet - Page 4

• Manufacturer Part Number: LT3463EDD#TRPBF
• Description: IC CONV DC/DC DUAL MICRPWR 10DFN
• Manufacturer: Linear Technology
• Type: Invertingr

Specifications of LT3463EDD#TRPBF

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 2
• Voltage - Output: 1.25 ~ 40 V
• Current - Output: 250mA
• Voltage - Input: 2.4 ~ 15 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Frequency - Switching: -

PI FU CTIO S
BLOCK DIAGRA
OPERATIO
LT3463/LT3463A
SHDN1 (Pin 9): Shutdown Pin for Switcher 1. Pull this pin
above 1.5V to enable Switcher 1. Pull below 0.3V to turn
it off. Do not leave this pin floating.
FB1 (Pin 10): Feedback Pin for Switcher 1. Set the output
voltage by selecting values for R1 and R2.
The LT3463 uses a constant off-time control scheme to
provide high efficiency over a wide range of output cur-
rent. Operation can be best understood by referring to the
block diagram in Figure 1. When the voltage at the FB1 pin
is slightly above 1.25V, comparator A1 disables most of
the internal circuitry. Output current is then provided by
capacitor C2, which slowly discharges until the voltage at
the FB1 pin goes below the hysteresis point of A1 (typical
hysteresis at the FB1 pin is 8mV). A1 then enables the
internal circuitry, turns on power switch Q1, and the
4
SHDN1
V
U
OUT1
R2
R1
10
9
LT3463: R
LT3463A: R
V
1.25V
IN
U
FB1
SHDN1
V
3
IN
S1
S1
–
+
= R
= 0.1 , R
U
S2
U
= 0.1
A1
S2
C1
= 0.063
SWITCHER 1
W
ONE-SHOT
300ns
L1
A2
2
SW1
+
–
V
OUT1
25mV
Figure 1. Block Diagram
C2
1
Q1
V
V
R
OUT2
OUT1
D1
S1
C3
D3
11
GND
GND (Pin 11): Exposed Pad. Solder this exposed pad
directly to the local ground plane. This pad must be
electrically connected for proper operation.
current in inductor L1 begins ramping up. Once the switch
current reaches 250mA, comparator A2 resets the one-
shot, which turns off Q1 for 300ns. Q1 turns on again and
the inductor currents ramp back up to 250mA, then A2
again resets the one-shot. This switching action continues
until the output voltage is charged up (until the FB1 pin
reaches 1.25V), then A1 turns off the internal circuitry and
the cycle repeats. The second switching regulator is an
inverting converter (which generates a negative output)
but the basic operation is the same.
5
D2
D2
C4
R
S2
Q2
4
SW2
25mV
L2
+
–
V
IN
A4
SWITCHER 2
ONE-SHOT
300ns
A3
1.25V
+
–
SHDN2
V
REF
FB2
3463 F01
8
7
6
V
OUT2
SHDN2
R3
R4
3463f