MAX8717ETI Maxim Integrated, MAX8717ETI Datasheet - Page 11

• Manufacturer Part Number: MAX8717ETI
• Description: Current & Power Monitors & Regulators
• Manufacturer: Maxim Integrated

MAX8716
Interleaved High-Efficiency, Dual Power-Supply
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10
11
12
13
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5
1
2
3
4
6
7
8
9
PIN
MAX8717/
MAX8756/
MAX8757
10
11
12
13
14
15
1
2
3
4
5
7
8
9
6
______________________________________________________________________________________
PGOOD2
NAME
ILIM2
CSH2
Controllers for Notebook Computers
CSL2
BST2
FSEL
ON1
ON2
DH2
REF
FB2
V
LX2
CC
Analog Supply Input. Connect to the system supply voltage (+4.5V to +5.5V) through a
series 20 resistor. Bypass V
Low-Noise Mode Control for SMPS1. Connect
(pulse-skipping) operation or to V
for low-noise mode.
2.0V Reference Voltage Output. Bypass REF to AGND with a 0.1μF or greater ceramic
capacitor. The reference can source up to 50μA. Loading REF degrades output voltage
accuracy according to the REF load-regulation error (see the Typical Operating
Characteristics). The reference shuts down when both ON1 and ON2 are low.
Low-Noise Mode Control for SMPS2. Connect
(pulse-skipping) operation or to V
for low-noise mode.
Frequency Select Input. This four-level logic input sets the controller’s switching
frequency.
SMPS2 Enable Input. Drive ON2 high to enable SMPS2. Drive ON2 low to shut down
SMPS2.
SMPS2 Peak Current-Limit Threshold Adjustment. Connect ILIM2 to V
default 50mV current-limit threshold. In adjustable mode, the current-limit threshold across
CSH2 and CSL2 is precisely 1/10 the voltage seen at ILIM2 over a 500mV to 2.0V range.
The logic threshold for switchover to the 50mV default value is approximately V
SMPS2 Open-Drain Power-Good Output. PGOOD2 is low when SMPS2 is more than 10%
below its regulation threshold, during soft-start, and in shutdown.
Feedback Input for SMPS2. Connect FB2 to V
MAX8716/MAX8717/MAX8757, or a fixed 1.8V for the MAX8756. In adjustable mode,
FB2 regulates to 1V.
Negative Current-Sense Input for SMPS2. Connect to the negative terminal of the
current-sense element. Figure 8 describes two different current-sensing options.
Positive Current-Sense Input for SMPS2. Connect to the positive terminal of the current-
sense element. Figure 8 describes two different current-sensing options.
Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor and
diode as shown in Figure 1. An optional resistor in series with BST2 allows the DH2
turn-on current to be adjusted.
High-Side Gate-Driver Output for SMPS2. DH2 swings from LX2 to BST2.
Inductor Connection for SMPS2. Connect LX2 to the switched side of the inductor. LX2
is the lower supply rail for the DH2 high-side gate driver.
SMPS1 Enable Input. Drive ON1 high to enable SMPS1. Drive ON1 low to shut down
SMPS1.
FSEL
GND
V
REF
CC
CC
MAX8717/MAX8757 (kHz)
to AGND with a 1μF or greater ceramic capacitor.
CC
CC
for PWM mode (fixed frequency). Connect to REF
for PWM mode (fixed frequency). Connect to REF
FUNCTION
500
300
200
CC
for fixed 5V output for the
to GND for normal Idle Mode
to GND for normal Idle Mode
Pin Description
CC
MAX8756 (kHz)
to enable the
400
300
250
CC
- 1V.
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