LTC1840CGN Linear Technology, LTC1840CGN Datasheet - Page 6

• Manufacturer Part Number: LTC1840CGN
• Description: IC DUAL FAN CONTROLLER 16-SSOP
• Manufacturer: Linear Technology

Specifications of LTC1840CGN

• Applications: Fan Controller
• Number Of Outputs: 2
• Current - Output: 10mA
• Voltage - Supply: 2.7 V ~ 5.75 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Load: -

PI FU CTIO S
BLOCK DIAGRA
LTC1840
BLAST (Pin 13): Blast/Timer Function Input. This is a
multifunction digital input pin that controls blast and timer
operation. If this pin is in a logic high state at power-up or
is transitioned from high to low, it will “blast” the current
DAC outputs to full scale (100 A) no matter what their
previous state was and set a fault condition. In addition, if
BLAST is in a logic high state, the serial access timer is
active; this circuit measures time between serial commu-
nications to the LTC1840 and forces a blast and trips a fault
if the part hasn’t been accessed for about 1.5 minutes. This
pin has a 1V logic threshold.
I
impedance output with a sinking current output of 0 A to
TI I G DIAGRA
6
DACOUTB
U
W
U
(Pin 14): Current DAC Output B. This is a high
U
SDA
SCL
A1
A0
SDA
t
SCL
hD, STA
1
2
3
4
CONDITION
START
U
INTERFACE
SERIAL
8
t
LOW
W
t
GND
r
W
t
HIGH
t
su, DAT
I
DACOUTA
REF
15
INTERFACE
COUNTER
IDACs
GPI/O
8-BIT
8-BIT
I
t
f
I
DACOUTB
t
14
hD, DAT
OSC
I
8, 16
2, 4,
DETECT
FAULT
FAULT
REPEATED START
5
CONDITION
TACHB
12
BLAST
13
t
100 A. This current can be programmed to one of 256
values through the serial interface or it can be “blasted”
immediately to full scale using the BLAST pin or by the
serial access timer if it is enabled and the LTC1840 is not
accessed for about 1.5 minutes. This pin will maintain the
programmed current to a very tight tolerance from as low
as 1.1V to at least 0.75V above V
guaranteed to be monotonic over its full 8-bit range.
I
V
decoupled to ground (pin 8). A 10 F tantalum and a 0.1 F
ceramic capacitor in parallel are recommended.
su, STA
DACOUTA
CC
COUNTER
TACHA
8-BIT
11
(Pin 16): Positive Supply. This pin must be closely
t
hD, STA
(Pin 15): Current DAC Output A. See I
t
su, STO
CONDITION
STOP
t
BUF
CONDITION
CC
START
1840 BD
. The current DAC is
1840 TD01
10
6
7
9
GPIO1
GPIO2
GPIO3
GPIO4
DACOUTB
1840f