ISL6353 Datasheet, PDF (4/30 Pages) Intersil Corporation – Multiphase PWM Regulator for VR12 DDR Memory Systems

Pin Configuration
ISL6353
ISL6353
(40 LD TQFN)
TOP VIEW
40 39 38 37 36 35 34 33 32 31
SDA 1
ALERT# 2
SCLK 3
VR_ON 4
PGOOD 5
IMON 6
VR_HOT# 7
NTC 8
VW 9
COMP 10
GND
(BOTTOM PAD)
30 LG2
29 VDDP
28 PWM3
27 LG1
26 GND
25 PH1
24 UG1
23 BOOT1
22 PROG1
21 VIN
11 12 13 14 15 16 17 18 19 20
Pin Descriptions
PIN NUMBER
SYMBOL
DESCRIPTION
1, 2, 3 SDA, ALERT#, SCLK Serial communication bus signals connected between the CPU and the voltage regulator.
4
VR_ON
Voltage regulator enable input. A high level logic signal on this pin enables the VR.
5
PGOOD
Open-drain output to indicate the regulator is ready to supply regulated voltage. Use an appropriate external pull-up
resistor.
6
IMON
Output current monitor pin. IMON sources a current proportional to the regulator output current. A resistor
connected from this pin to ground will set a voltage that is proportional to the load current. This voltage is sampled
with an internal ADC to produce a digital IMON signal that can be read through the serial communications bus.
7
VR_HOT#
Thermal overload output indicator.
8
NTC
Thermistor input to the VR_HOT# circuit.
9
VW
Window voltage set pin used to set the switching frequency. A resistor from this pin to COMP programs the
switching frequency (18kΩ gives approximately 300kHz).
10
COMP
This pin is the output of the error amplifier.
11
FB
This pin is the inverting input of the error amplifier.
12
FB2
This pin switches in an RC network from VOUT to FB in PS1 and PS2 modes to help improve transient performance
and phase margin when dropping phases in low power states. There is a switch between the FB2 pin and the FB
pin. The switch is off in the PS0 state and on in the PS1 and PS2 states. If this function is not needed, the pin can
be left open.
13
ISEN3
Individual current sensing input for Phase 3. Leave this pin open when ISL6353 is configured in 2-phase mode.
14
ISEN2
Individual current sensing input for Phase 2. When ISEN2 is pulled to 5V VDD, the controller will disable Phase 2,
and the controller will run in 1-phase mode.
15
ISEN1
Individual current sensing input for Phase 1.
16
VSEN
Output voltage sense pin. Connect to the output voltage (typically VDDQ) at the desired remote voltage sensing
location.
4
September 15, 2011
FN6897.0