MAX1714AEEP Ver la hoja de datos (PDF) - Maxim Integrated
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MAX1714AEEP Datasheet PDF : 24 Pages
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High-Speed Step-Down Controller
for Notebook Computers
Table 1. Component Selection for Standard Applications
COMPONENT
Input Range
Frequency
Q1 High-Side
MOSFET
2.5V AT 4A
7V to 20V
300kHz
Fairchild Semiconductor
1/2 FDS6982A
1.6V AT 8A
7V to 20V
300kHz
International Rectifier
IRF7811
Q2 Low-Side
MOSFET
Fairchild Semiconductor
1/2 FDS6982A
Fairchild Semiconductor
FDS6670A
D2 Rectifier
Nihon EP10QY03
Motorola MBRS340T3
L1 Inductor
6.8µH
Coilcraft DO3316P-682
1.5µH
Sumida CEP1251R5MC
C1 Input Capacitor
10µF, 25V
Taiyo Yuden TMK432BJ106KM
(2) 10µF, 25V
Taiyo Yuden TMK432BJ106KM
C2 Output Capacitor
470µF, 6V
Kemet T510X477108M006AS
(2) 470µF 6V
Kemet T510X477108M006AS
2.5V AT 1.5A
4.5V to 5.5V
600kHz
International Rectifier
1/2 IRF7301
International Rectifier
1/2 IRF7301
Motorola MBR0520LT1
3.3µH
Coiltronics UP1B-3R3
100µF, 10V
Sanyo POSCAP 10TPA100M
100µF, 10V
Sanyo POSCAP 10TPA100M
Table 2. Component Suppliers
MANUFACTURER
AVX
Central Semiconductor
Coilcraft
Coiltronics
Fairchild
International Rectifier
Kemet
Matsuo
Motorola
USA PHONE
803-946-0690
516-435-1110
847-639-6400
561-241-7876
408-822-2181
310-322-3331
408-986-0424
714-969-2491
602-303-5454
FACTORY FAX
[Country Code]
[1] 803-626-3123
[1] 516-435-1824
[1] 847-639-1469
[1] 561-241-9339
[1] 408-721-1635
[1] 310-322-3332
[1] 408-986-1442
[1] 714-960-6492
[1] 602-994-6430
Murata
814-237-1431
800-831-9172
[1] 814-238-0490
NIEC (Nihon)
Sanyo
805-867-2555* [81] 3-3494-7414
619-661-6835 [81] 7-2070-1174
Siliconix
408-988-8000
800-554-5565
[1] 408-970-3950
Sprague
Sumida
Taiyo Yuden
TDK
603-224-1961
847-956-0666
408-573-4150
847-390-4461
[1] 603-224-1430
[81] 3-3607-5144
[1] 408-573-4159
[1] 847-390-4405
*Distributor
+5V Bias Supply (VCC and VDD)
The MAX1714 requires an external +5V bias supply in
addition to the battery. Typically, this +5V bias supply is
the notebook’s 95% efficient +5V system supply.
Keeping the bias supply external to the IC improves effi-
ciency and eliminates the cost associated with the +5V
linear regulator that would otherwise be needed to sup-
ply the PWM circuit and gate drivers. If stand-alone
capability is needed, the +5V supply can be generated
with an external linear regulator such as the MAX1615.
The battery and +5V bias inputs can be tied together if
the input source is a fixed +4.5V to +5.5V supply. If the
+5V bias supply is powered up prior to the battery sup-
ply, the enable signal (SHDN) must be delayed until the
battery voltage is present in order to ensure startup. The
+5V bias supply must provide VCC and gate-drive
power, so the maximum current drawn is:
IBIAS = ICC + f (QG1 + QG2) = 5mA to 30mA (typ)
where ICC is 600µA typical, f is the switching frequency,
and QG1 and QG2 are the MOSFET data sheet total
gate-charge specification limits at VGS = 5V.
Free-Running, Constant-On-Time PWM
Controller with Input Feed-Forward
The Quick-PWM control architecture is a pseudo-fixed-fre-
quency, constant-on-time current-mode type with voltage
feed-forward (Figure 2). This architecture relies on the out-
put filter capacitor’s ESR to act as the current-sense resis-
tor, so the output ripple voltage provides the PWM ramp
signal. The control algorithm is simple: the high-side
switch on-time is determined solely by a one-shot whose
period is inversely proportional to input voltage and direct-
ly proportional to output voltage. Another one-shot sets a
minimum off-time (400ns typical). The on-time one-shot is
triggered if the error comparator is low, the low-side switch
current is below the current-limit threshold, and the mini-
mum off-time one-shot has timed out.
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