MAX1760ETB+T Maxim Integrated Products, MAX1760ETB+T Datasheet - Page 10

• Manufacturer Part Number: MAX1760ETB+T
• Description: IC DC-DC CONV STP UP 10-TDFN
• Manufacturer: Maxim Integrated Products
• Type: Step-Up (Boost)r

Specifications of MAX1760ETB+T

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 3.3V, 2.5 ~ 5.5 V
• Current - Output: 800mA
• Frequency - Switching: 1MHz
• Voltage - Input: 0.7 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TDFN Exposed Pad
• Power - Output: 1.48W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

time constant is:
where R
Placing a capacitor across the lower resistor of the cur-
rent-limiting resistive divider provides both current-limit
and soft-start features simultaneously (Figures 4 and 5).
The MAX1760’s high switching frequency allows the
use of a small 3.3µH surface-mount inductor. The cho-
sen inductor should generally have a saturation current
rating exceeding the N-channel switch current limit;
however, it is acceptable to bias the inductor current
into saturation by as much as 20% if a slight reduction
in efficiency is acceptable. Lower current-rated induc-
tors may be used if ISET is employed to reduce the
peak inductor current (see the Setting the Switch
Current Limit and Soft-Start section). For high efficien-
cy, choose an inductor with a high-frequency ferrite
core material to reduce core losses. To minimize radiat-
ed noise, use a toroid or shielded inductor. See Table 3
for suggested components and Table 4 for a list of
component suppliers. Connect the inductor from the
battery to the LX pin as close to the IC as possible.
0.8A, Low-Noise, 1MHz,
Step-Up DC-DC Converter
Table 3. Component Selection Guide
Table 4. Component Suppliers
Note: Please indicate that you are using the MAX1760 when
contacting these component suppliers.
10
PRODUCTION METHOD
SUPPLIER
______________________________________________________________________________________
Motorola
Sumida
Kemet
TOKO
AVX
Surface mount
EIC
SS
470k .
USA: 843-448-9411
USA: 916-941-0712
USA: 810-287-2536
USA: 408-629-4789
Japan: 81-45-474-7030
USA: 847-956-0666
Japan: 011-81-3-3667-3302
USA: 847-297-0070
t
SS
R C
SS
Inductor Selection
SS
PHONE
TOKO type D518LC
Sumida CDRH5D18
Sumida CDRH4D28
TOKO type D52LC
INDUCTORS
For output voltages greater than 4V, an external
Schottky diode must be connected from LX to POUT, in
parallel with the on-chip synchronous rectifier (Figure
6). The diode should be rated for 0.5A. Representative
devices are Motorola MBR0520L, Nihon EP05Q03L, or
generic 1N5817. This external diode is also recom-
mended for applications that must start with input volt-
ages at or below 1.8V. The Schottky diode carries
current during startup and after the synchronous rectifi-
er turns off; thus, its current rating only needs to be
500mA. Connect the diode as close to the IC as possi-
ble. Do not use ordinary rectifier diodes; their slow
switching speeds and long reverse-recovery times ren-
der them unacceptable. For circuits that do not require
startup with inputs below 1.8V and have an output of 4V
or less, no external diode is needed.
Choose input and output filter capacitors that will ser-
vice the input and output peak currents with accept-
able voltage ripple. Choose input capacitors with
working voltage ratings over the maximum input volt-
Figure 6. Connection with External Schottky Diode for Output
Voltages Greater than 4V, or to Assist Low-Voltage Startup
V
TO VOUT
IN
Sanyo POSCAP series
= 0.7V
Kemet T510 series
AVX TPS series
CAPACITORS
0.22 F
Input and Output Filter Capacitors
—
33 F
ISET
REF
ON
CLK/SEL
PGND GND
MAX1760
3.3 H
POUT
FB
OUT
LX
Motorola MBR0520L
EIC SB series
External Diode
MRB0520L
DIODES
4.7
0.68 F
—
—
100 F
V
OUT