Pin description – Rainbow Electronics MAX786 User Manual
Page 7
MAX786
Dual-Output Power-Supply
Controller for Notebook Computers
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7
PIN
NAME
FUNCTION
1
CS3
Current-sense input for +3.3V; +100mV = current limit level referenced to FB3.
2
SS3
Soft-start input for +3.3V. Ramp time to full current limit is 1ms/nF of capacitance to GND.
3
ON3
ON/OFF control input disables the +3.3V PWM. Tie directly to VL for automatic start-up.
4
D1
#1 level-translator/comparator noninverting input, threshold = +1.650V. Controls Q1. Tie to GND if unused.
5
D2
#2 level-translator/comparator noninverting input (see D1)
6
VH
External positive supply-voltage input for the level translators/comparators
7
Q2
#2 level-translator/comparator output. Sources 20µA from VH when D2 is high. Sinks 500µA to GND
when D2 is low, even with VH = 0V.
8
Q1
#1 level translator/comparator output (see Q2)
9
GND
Low-current analog ground
10
REF
3.3V reference output. Sources up to 5mA for external loads. Bypass to GND with 1µF/mA of load or
0.22µF minimum.
11
SYNC
Oscillator control/synchronization input. Connect to VL or GND for 200kHz; connect to REF for
300kHz. For external clock synchronization in the 240kHz to 350kHz range, a high-to-low transition
causes a new cycle to start.
12
SHDN
Shutdown control input, active low. Tie to VL for automatic start-up. The 5V VL supply stays active in
shutdown, but all other circuitry is disabled. Do not force SHDN higher than VL + 0.3V.
13
ON5
ON/OFF control input disables the +5V PWM supply. Tie to VL for automatic start-up.
14
SS5
Soft-start control input for +5V. Ramp time to full current limit is 1ms/nF of capacitance to GND.
15
CS5
Current-sense input for +5V; +100mV = current-limit level referenced to FB5.
16
DH5
Gate-drive output for the +5V high-side MOSFET
17
LX5
Inductor connection for the +5V supply
18
BST5
Boost capacitor connection for the +5V supply (0.1µF)
19
DL5
Gate-drive output for the +5V low-side MOSFET
20
PGND
Power ground
21
FB5
Feedback and current-sense input for the +5V PWM
22
VL
5V logic supply voltage for internal circuitry. VL is always on and can source 5mA for external loads.
23
V+
Supply voltage input from battery, 5.5V to 30V
24
DL3
Gate-drive output for the +3.3V low-side MOSFET
25
BST3
Boost capacitor connection for the +3.3V supply (0.1µF)
26
LX3
Inductor connection for the +3.3V supply
27
DH3
Gate-drive output for the +3.3V high-side MOSFET
28
FB3
Feedback and current-sense input for the +5V PWM
_______________________________________________________________________Pin Description