MAX6620ATI+ Maxim Integrated Products, MAX6620ATI+ Datasheet - Page 7

• Manufacturer Part Number: MAX6620ATI+
• Description: IC QUAD LIN FAN-SPD CTRLR 28TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX6620ATI+

• Applications: Fan Controller
• Number Of Outputs: 4
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

12, 17, 19, 24
13, 16, 20, 23
14, 15, 21, 22
4, 10, 11, 18,
PIN
8, 9
25
26
27
28
—
1
2
3
5
6
7
S P IN U P _S TART
TACH4–TACH1 Fan Tachometer Logic Inputs. These inputs accept input voltages up to V
DAC_START
WD_START
DACOUT4–
DACOUT1
FAN_FAIL
DACFB4–
DACFB1
_______________________________________________________________________________________
NAME
X1, X2
ADDR
GND
SDA
VCC
SCL
FAN
EP
I
Open-Drain, I
circuit when V
Startup Watchdog Set Input. This input is sampled when power is first applied and sets the initial
I
connected to V
fan drive goes to 100%.
Ground
I
address. When connected to GND, the slave address will be 0x50. When unconnected, the slave
address will be 0x52. When connected to V
Startup Fan Drive DAC Set Input. This input is sampled when power is first applied and sets the
power-up value for the fan drive voltage. When connected to GND, the fan drive voltage will be
0%. When unconnected, the fan drive voltage will be 75%. When connected to V
voltage will be 100%.
Startup Spin-Up Set Input. This input is sampled when power is first applied and sets the initial
spin-up behavior. When connected to GND, spin-up is disabled. When connected to V
power-up, the fan is driven with a full-scale drive voltage until two tachometer pulses have been
detected, or 1s has elapsed. When unconnected, the fan is driven with a full-scale drive voltage
until two tachometer pulses have been detected, or 0.5s has elapsed. Spin-up behavior may be
modified by writing appropriate settings to the MAX6620’s registers.
Crystal Oscillator Inputs. Connections for a standard 32.768kHz quartz crystal. The internal
oscillator circuitry is designed for operation with a crystal having a specified load capacitance
(C
external oscillator. If no crystal or external oscillator is connected, the MAX6620 will use its
internal oscillator.
Fan Drive DAC Outputs. Connect to the gate of a p-channel MOSFET or base of a PNP bipolar
transistor.
D AC Feed b ack Inp uts. C onnect a 0.1µF cap aci tor b etw een these p i ns and GN D . C onnect to the
sup p l y p i n of the fan and to the d r ai n of a p - channel M O S FE T or col l ector of a P N P b i p ol ar tr ansi stor .
Fan Power-Supply Voltage Input. Connect to the fan power supply (V
capacitor to GND.
Power-Supply Input. 3.3V nominal. Bypass V
Active-Low, Open-Drain Fan Failure Output. Active only when fault is present; open-circuit when
V
Exposed Paddle. Internally connected to GND. Connect to a large ground plane to maximize
thermal performance. Not intended as an electrical connection point.
2
2
2
C Serial-Clock Input. Can be pulled up to 5.5V regardless of V
C watchdog behavior. When connected to GND, the watchdog function is disabled. When
C Address Set Input. This input is sampled when power is first applied and sets the I
CC
L
) of 12pF. Connect an external 32.768kHz oscillator across X1 and X2 for operation with the
Quad Linear Fan-Speed Controller
= 0V. This pin can be pulled up to 5.5V regardless of V
2
CC
C Serial-Data Input/Output. Can be pulled up to 5.5V regardless of V
CC
= 0V.
, the MAX6620 monitors SDA. If 10s elapse without a valid I
CC
FUNCTION
CC
, the slave address will be 0x54.
to GND with a 0.1µF capacitor.
CC
.
CC
. Open circuit when V
FAN
Pin Description
). Bypass with a 0.1µF
FAN
2
.
C transaction, the
CC
CC
, the fan drive
. Open
2
CC
C slave
CC
at
= 0V.
7