MAX1669 Datasheet, PDF (6/20 Pages) Maxim Integrated Products – Fan Controller and Remote Temperature Sensor with SMBus Serial Interface

Fan Controller and Remote Temperature Sensor
with SMBus Serial Interface
Typical Operating Characteristics (continued)
(Temperature error = measured - actual, T_A = +25°C, unless otherwise noted.)
PWM DUTY FACTOR vs. CODE (D3D2D1D0)
100
V_CC = +3.3V OR +5V
80
60
40
20
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CODE (D3D2D1D0)
DAC OUTPUT vs. CODE (D3D2D1D0)
5.0
4.5
I_LOAD = +10mA TO -10mA
V_CC = +5V
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
CODE (D3D2D1D0)
Pin Description
PIN
NAME
FUNCTION
1
I/O1
General-Purpose Open-Drain Logic Input/Output 1. I/O1 is intended for driving LEDs, driving power-plane
switching MOSFETs, or detecting fan presence or chassis intrusion.
2
I/O2
General-Purpose Open-Drain Logic Input/Output 2. I/O2 is intended for driving LEDs, driving power-plane
switching MOSFETs, or detecting fan presence or chassis intrusion.
3
ADD0
SMBus Address Select Pin 0. See Table 11.
4
ADD1
SMBus Address Select Pin 1. See Table 11.
5
ADD2
SMBus Address Select Pin 2. See Table 11.
6
AGND
Analog Ground
7
DXN
Combined Current Sink and ADC Negative Input from Remote Diode. DXN is normally biased to a diode
voltage above ground.
8
DXP
Combined Current Source and ADC Positive Input from Remote Diode. Place a 2200pF capacitor
between DXP and DXN for noise filtering.
9
V_CC
Supply Voltage Input, +3V to +5.5V. Bypass to AGND with a 0.1µF capacitor.
Oscillator Synchronization Input. Connect to AGND to use internal clock. Capture range is 140kHz to
10
SYNC
400kHz. The synchronization signal is internally applied to the FAN PWM clock. See Table 5 for synchro-
nized frequencies.
11
FAN
Fan-Control Logic Output. Swings from PGND to V_CC in PWM mode, or PGND to 0.94 · V_CC in DAC mode.
12
PGND
Power Ground
13
SMBCLK SMBus Serial-Clock Input
14 SMBDATA Open-Drain SMBus Serial-Data Input/Output
15
ALERT
Active-Low, Open-Drain SMBus Alert (interrupt) Output
16
OVERT
Active-Low, Open-Drain Thermostat Output. Activated by T_CRIT threshold
6 _______________________________________________________________________________________