MAX786CAI+T Maxim Integrated Products, MAX786CAI+T Datasheet - Page 8

• Manufacturer Part Number: MAX786CAI+T
• Description: IC CNTRLR PWR SUP DL 28SSOP
• Manufacturer: Maxim Integrated Products
• Type: Step-Down (Buck)r

Specifications of MAX786CAI+T

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 3.3V, 5V
• Current - Output: 3A
• Frequency - Switching: 200kHz, 300kHz
• Voltage - Input: 5.5 ~ 30 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Power - Output: 762mW
• Output Voltage: 3.3 V, 3.45 V, 3.6 V
• Input Voltage: 5.5 V to 30 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Dual-Output Power-Supply
Controller for Notebook Computers
The MAX786 converts a 5.5V to 30V input to four outputs
(Figure 1). It produces two high-power, PWM, switch-
mode supplies, one at +5V and the other at +3.3V. The
two supplies operate at either 300kHz or 200kHz,
allowing for small external components. Output current
capability depends on external components, and can
exceed 6A on each supply. An internal 5V, 5mA supply
(VL) and a 3.3V, 5mA reference voltage are also gener-
ated via linear regulators, as shown in Figure 2. Fault
protection circuitry shuts off the PWMs when the inter-
nal supplies lose regulation.
Two precision voltage comparators are also included.
Their output stages permit them to be used as level
translators for driving external N-channel MOSFETs in
load-switching applications, or for more conventional
logic signals.
Figure 1. MAX786 Application Circuit
8
_________________Detailed Description
_______________________________________________________________________________________
+3.3V
150 F
AT
3A
C7
NOTE 1:
NOTE 2:
150 F
C12
INPUT VOLTAGE RANGE 6.5V TO 30V
AS SHOWN. SEE LOW-VOLTAGE
(6-CELL) OPERATION SECTION FOR
DETAILS.
USE SHORT, KELVIN-CONNECTED PC
BOARD TRACES PLACED VERY CLOSE
TO ONE ANOTHER.
5.5V TO 30V
(NOTE 1)
+3.3V ON/OFF
25m
+5V ON/OFF
SHUTDOWN
INPUT
OSC SYNC
R1
33 F
C1
1N5819
D1
10 H
L1
(NOTE 2)
N1
N3
0.01 F
C9
0.1 F
C5
1N4148
D2A
28
25
27
26
24
13
12
11
1
2
3
BST3
DH3
LX3
DL3
CS3
FB3
SS3
ON3
ON5
SHDN
SYNC
GND
9
V+
MAX786
23
REF
10
C3
1 F
The MAX786 has two close relatives: the MAX782 and
the MAX783. The MAX782 and MAX783 each include
an extra flyback winding regulator and linear regulators
for dual, +12V/programmable PCMCIA VPP outputs.
The MAX782/MAX783 data sheet contains extra appli-
cations information on the MAX786 not found in this
data sheet.
The +3.3V supply is generated by a current-mode,
PWM step-down regulator using two N-channel
MOSFETs, a rectifier, and an LC output filter (Figure 1).
The gate-drive signal to the high-side MOSFET, which
must exceed the battery voltage, is provided by
a boost circuit that uses a 100nF capacitor connected
to BST3.
VL
PGND
BST5
DH5
LX5
CS5
SS5
DL5
FB5
22
VH
D1
Q1
D2
Q2
20
18
16
17
19
15
21
14
6
4
8
5
7
D2B
1N4148
C4
0.1 F
C8
0.01 F
(NOTE 2)
N4
+3.3V Switch-Mode Supply
N2
10 H
COMPARATOR SUPPLY INPUT
IN
OUT
IN
OUT
L2
D3
1N5819
+3.3V AT 5mA
COMPARATOR 2
COMPARATOR 1
4.7 F
C10
33 F
25m
R2
+5V AT 5mA
+5V
AT
3A
C6
330 F