MAX771ESA+ Maxim Integrated Products, MAX771ESA+ Datasheet - Page 9

• Manufacturer Part Number: MAX771ESA+
• Description: IC CNTRLR DC-DC 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Step-Up (Boost)r

Specifications of MAX771ESA+

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 12V, Adj
• Current - Output: 1A
• Frequency - Switching: 300kHz
• Voltage - Input: 2 ~ 16.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Power - Output: 471mW
• Output Voltage: 12 V or 3 V (Min)
• Output Current: 1 A (Max)
• Input Voltage: 2 V to 16.5 V
• Supply Current: 110 uA
• Switching Frequency: 300 KHz
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 1. Block Diagram
Floating the shunt-regulator ground (SGND) disables
the shunt regulator. To enable it, connect SGND to
GND. The shunt regulator requires 1mA minimum cur-
rent for proper operation; the maximum current must
not exceed 20mA. The MAX773 operates in non-boot-
strapped mode when the shunt regulator is used, and
EXT swings between the 6V shunt-regulator voltage
and GND.
When using the shunt regulator, use an N-channel pow-
er FET instead of an NPN power transistor as the power
switch. Otherwise, excessive base drive will collapse
the shunt regulator.
REF
LBI
ONE-SHOT
TRIG
5V/12V/15V or Adjustable, High-Efficiency,
Q
_______________________________________________________________________________________
LBO V15
S
REFERENCE
ONE-SHOT
Q
N
1.5V
F/F
R
V+
TRIG
Q
MAX773 ONLY
V12
COMPARATOR
LOW-VOLTAGE
OSCILLATOR
Low I
ERROR
V5
CURRENT-SENSE
N
AMPLIFIER
Q
, Step-Up DC-DC Controllers
FB
The MAX770–MAX773 use a proprietary current-limited
PFM control scheme to provide high efficiency over a
wide range of load currents. This control scheme com-
bines the ultra-low supply current of PFM converters (or
pulse skippers) with the high full-load efficiency of
PWM converters.
Unlike traditional PFM converters, the MAX770–
MAX773 use a sense resistor to control the peak induc-
tor current. They also operate with high switching
200mV
CONTROL
EXT
0.2V
DUAL-MODE
COMPARATOR
0.1V
N
MAX770–MAX773
2.5V
MAX770
MAX771
MAX772
External Power-Transistor
PFM Control Scheme
Control Circuitry
CIRCUITRY
BIAS
6V
SHDN
V+
SGND
EXTH
MAX773
ONLY
EXTL
EXT
MAX770
MAX771
MAX772
CS
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