LTC2930HDD#PBF Linear Technology, LTC2930HDD#PBF Datasheet - Page 7

• Manufacturer Part Number: LTC2930HDD#PBF
• Description: IC 6 POWER SUPPLY MONITOR 12DFN
• Manufacturer: Linear Technology

Specifications of LTC2930HDD#PBF

• Applications: Six Power Supply Monitor
• Voltage - Supply: 1 V ~ 7 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 12-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Voltage - Input: -

APPLICATIONS INFORMATION
Supply Monitoring
The LTC2930 is a low power, high accuracy confi gurable six
supply monitoring circuit with a common reset output. An
external capacitor sets the reset timeout period. An external
resistive divider between VREF , VPG and GND selects 1 of
16 possible input voltage monitor combinations. All six volt-
age inputs must be above their predetermined thresholds
for the reset not to be activated. The LTC2930 asserts the
reset output during power-up, power-down and brownout
conditions on any one of the voltage inputs.
Power-Up
The greater of V1 and V2 serves as the internal supply
voltage (V
for the RST pin. This ensures that the RST output will be
low as soon as either V1 or V2 reaches 1V. The RST output
remains low until the part is confi gured. Once voltage
thresholds are set, if any of the supply monitor inputs is
below its confi gured threshold, RST will be a logic low.
Once all the monitor inputs rise above their thresholds,
an internal timer is started and RST is released after the
delay time. If V
input impedance will be low (10kΩ typical).
Threshold Accuracy
Consider a 5V system with ±5% tolerance. The 5V supply
may vary between 4.75V to 5.25V. System ICs powered by
this supply must operate reliably within this band (and a
little more as explained below). A perfectly accurate su-
Figure 1. 1.5% Threshold Accuracy Improves System Reliability
THRESHOLD
±1.5%
BAND
CC
4.675V
4.75V
). On power-up, V
4.6V
5V
CC
< (V3 – 1.0V) and V
MINIMUM
RELIABLE
VOLTAGE
SYSTEM
REGION OF POTENTIAL MALFUNCTION
SUPPLY TOLERANCE
CC
powers the drive circuits
SUPERVISOR
THRESHOLD
IDEAL
CC
< 2.4V, the V3
NOMINAL
SUPPLY
VOLTAGE
–5%
–6.5%
–8%
Table 1. Voltage Threshold Modes*
*V5 and V6 are always adjustable (ADJ).
pervisor for this supply generates a reset at exactly 4.75V,
however no supervisor is this perfect. The actual reset
threshold of a supervisor varies over a specifi ed band;
the LTC2930 varies ±1.5% around its nominal threshold
voltage (see Figure 1) over temperature.
The reset threshold band and the power supply tolerance
bands should not overlap. This prevents false or nuisance
resets when the power supply is actually within its speci-
fi ed tolerance band.
The LTC2930 has a ±1.5% reset threshold accuracy, so a
“5%” threshold is typically set to 6.5% below the nominal
input voltage. Therefore, a typical 5V, “5%” threshold is
4.675V. The threshold is guaranteed to lie in the band be-
tween 4.750V and 4.600V over temperature. The powered
system must work reliably down to the low end of the
threshold band, or risk malfunction before a reset signal
is properly issued.
A less accurate supervisor increases the required system
voltage margin and increases the probability of system
malfunction. The LTC2930 ±1.5% specifi cation improves
the reliability of the system over supervisors with wider
threshold tolerances.
MODE V1 (V) V2 (V) V3 (V) V4 (V) R1 (kΩ) R2 (kΩ)
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
5.0
5.0
3.3
3.3
3.3
5.0
5.0
5.0
5.0
5.0
3.3
3.3
3.3
5.0
5.0
5.0
3.3
3.3
2.5
2.5
2.5
3.3
3.3
3.3
3.0
3.0
2.5
2.5
2.5
3.3
3.3
3.0
ADJ
ADJ
ADJ
ADJ
ADJ
1.5
2.5
2.5
2.5
2.5
1.8
1.8
1.8
1.8
1.8
1.8
–ADJ
–ADJ
–ADJ
–ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
1.8
1.5
1.5
Short
Open
93.1
86.6
78.7
71.5
66.5
59.0
53.6
47.5
40.2
34.8
28.0
22.1
16.2
9.53
LTC2930
Short
Open
9.53
16.2
22.1
28.0
34.8
40.2
47.5
53.6
59.0
66.5
71.5
78.7
86.6
93.1
0.000
0.094
0.156
0.219
0.281
0.344
0.406
0.469
0.531
0.594
0.656
0.719
0.781
0.844
0.906
1.000
V
V
REF
PG
2930fa
7