MAX1714BEEE+ Maxim Integrated Products, MAX1714BEEE+ Datasheet - Page 19

• Manufacturer Part Number: MAX1714BEEE+
• Description: IC CNTRLR STP DWN HS 16-QSOP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX1714BEEE+

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 2.5V, 3.3V, Adj
• Current - Output: 8A
• Frequency - Switching: 200kHz, 300kHz, 600kHz
• Voltage - Input: 2 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Power - Output: 667mW
• Output Voltage: 1 V to 5.5 V
• Output Current: 3000 mA
• Mounting Style: SMD/SMT
• Switching Frequency: 600 KHz
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Synchronous Pin: No
• Topology: Buck
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 5. Approximate K-Factor Errors
and bulk output capacitance must often be added (see
the V
Dropout Design Example: V
f = 300kHz. The required duty is (V
V
case on-time is (V
3.35µs-V · 90% = 2.08µs. The IC duty-factor limitation is:
which meets the required duty.
Figure 7. All-Ceramic-Capacitor Application
DUTY
SETTING
SW
(kHz)
TON
200
300
450
600
) = (2V + 0.1V) / (3.0V - 0.1V) = 72.4%. The worst-
SAG
* FOR HIGHER MINIMUM INPUT VOLTAGE,
*
=
LESS OUTPUT CAPACITANCE IS ACCEPTABLE.
t
equation in Transient Response section).
ON(MIN)
FACTOR
(µs)
3.3
2.2
1.7
K
5
t
V
ON(MIN)
IN
= 7V TO 24V*
+
OUT
______________________________________________________________________________________
t
OFF(MAX)
APPROXIMATE
+ 0.075) / V
ERROR (%)
K-FACTOR
ON/OFF
±12.5
±12.5
0.22µF
±10
±10
=
IN
1µF
2.08 s 500ns
= 3V min, V
IN
SHDN
SKIP
REF
TON
High-Speed Step-Down Controller
V+
OUT
2.08 s
µ
· K = 2.075V / 3V ·
ILIM
+
µ
( ) ARE FOR THE MAX1714B ONLY.
+ V
MAX1714
AT V
V
CC
MIN V
SW
PGND (GND)
AGND (GND)
OUT
OUT
2.6
2.9
3.2
3.6
(V)
20Ω
=
) / (V
IN
80.6%,
= 2V
= 2V,
OUT
BST
V
DH
LX
FB
DL
DD
IN
-
0.1µF
for Notebook Computers
5Ω
Remember to include inductor resistance and MOSFET
on-state voltage drops (V
dropout duty-factor calculations.
Ceramic capacitors have advantages and disadvan-
tages. They have ultra-low ESR, are noncombustible, are
relatively small, and are nonpolarized. On the other
hand, they’re expensive and brittle, and their ultra-low
ESR characteristic can result in excessively high ESR
zero frequencies (affecting stability). In addition, their rel-
atively low capacitance value can cause output over-
shoot when going abruptly from full-load to no-load
conditions, unless there are some bulk tantalum or elec-
trolytic capacitors in parallel to absorb the stored energy
in the inductor. In some cases, there may be no room for
electrolytics, creating a need for a DC-DC design that
uses nothing but ceramics.
The all-ceramic-capacitor application of Figure 7
replaces the standard, typical tantalum output capacitors
with ceramics in a 7A circuit. This design relies on hav-
ing a minimum of 5mΩ parasitic PC board trace resis-
tance in series with the capacitor in order to reduce the
ESR zero frequency. This small amount of resistance is
easily obtained by locating the MAX1714 circuit 2 or 3
inches away from the CPU, and placing all the ceramic
+5V
1µF
C1 = 2 x 10µF/25V TAIYO YUDEN (1812) (TMK432BJ106AM)
C2 = 6 x 47µF/6.3V TAIYO YUDEN (1812) (JMK432BJ476MN)
R1 + R2 = 5mΩ MINIMUM OF PCB TRACE RESISTANCE (TOTAL)
1k
Q1
Q2
All-Ceramic-Capacitor Application
0.5µH
C1
R1
R2
SW
) when doing worst-case
C2
2.5V AT 7A
CPU
19