参数资料
型号: LTC2912ITS8-1
厂商: LINEAR TECHNOLOGY CORP
元件分类: 电源管理
英文描述: 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8
封装: PLASTIC, MO-193, TSOT-23, 8 PIN
文件页数: 11/12页
文件大小: 168K
代理商: LTC2912ITS8-1
LTC2912
8
2912fa
APPLICATIONS INFORMATION
Power-Up/Power-Down
As soon as VCC reaches 1V during power up, the UV output
asserts low and the OV output weakly pulls to VCC.
The LTC2912 is guaranteed to assert UV low, OV high
(LTC2912-1, LTC2912-2) and OV low (LTC2912-3) under
conditions of low VCC, down to VCC = 1V. Above VCC = 2V
(2.1V maximum), the VH and VL inputs take control.
Once the VH input and VCC become valid an internal timer
is started. After an adjustable delay time, UV weakly pulls
high.
Threshold Accuracy
Reset threshold accuracy is important in a supply-sensitive
system. Ideally, such a system resets only if supply voltages
fall outside the exact thresholds for a specied margin.
Both LTC2912 inputs have a relative threshold accuracy
of ±1.5% over the full operating temperature range.
For example, when the LTC2912 is programmed to moni-
tor a 5V input with a 10% tolerance, the desired UV trip
point is 4.5V. Because of the ±1.5% relative accuracy of
the LTC2912, the UV trip point can be anywhere between
4.433V and 4.567V which is 4.5V ±1.5%.
Likewise, the accuracy of the resistances chosen for RA,
RB and RC can affect the UV and OV trip points as well.
Using the example just given, if the resistances used to
set the UV trip point have 1% accuracy, the UV trip range
is between 4.354V and 4.650V. This is illustrated in the
following calculations.
The UV trip point is given as:
VUV = 0.5V 1+
RC
RA + RB
The two extreme conditions, with a relative accuracy of
1.5% and resistance accuracy of 1%, result in:
VUV(MIN) = 0.5V 0.985 1+
RC 0.99
RA + RB
() 1.01
and
VUV(MAX) = 0.5V 1.015 1+
RC 1.01
RA + RB
() 0.99
For a desired trip point of 4.5V,
RC
RA + RB
= 8
Therefore,
VUV(MIN) = 0.5V 0.985 1+ 8
0.99
1.01
= 4.354V
and
VUV(MAX) = 0.5V 1.015 1+ 8
1.01
0.99
= 4.650V
Glitch Immunity
In any supervisory application, noise riding on the moni-
tored DC voltage causes spurious resets. To solve this
problem without adding hysteresis, which causes a new
error term in the trip voltage, the LTC2912 lowpass lters
the output of the rst stage comparator at each input. This
lter integrates the output of the comparator before as-
serting the UV or OV logic. A transient at the input of the
comparator of sufcient magnitude and duration triggers
the output logic. The Typical Performance Characteristics
show a graph of the Transient Duration vs Comparator
Overdrive.
UV/OV Timing
The LTC2912 has an adjustable timeout period (tUOTO) that
holds OV, OV or UV asserted after each fault has cleared.
This delay assures a minimum reset pulse width allowing
settling time for the monitored voltage after it has entered
the “valid” region of operation.
相关PDF资料
PDF描述
LT1076HVIT-5#TR 3.2 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PZFM5
LK1001-9EPD2T 1-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE
LK1001-9EPD9B1 1-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE
LK1001-9EPV2B1 1-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE
LK1301-9ERD1T 1-OUTPUT 150 W AC-DC REG PWR SUPPLY MODULE
相关代理商/技术参数
参数描述
LTC2912ITS8-1#PBF 制造商:Linear Technology 功能描述:MONITOR 29uA 6V TSOT-23-8 制造商:Linear Technology 功能描述:MONITOR, 29uA, 6V, TSOT-23-8; No. of Supervisors / Monitors:1; Supply Voltage Min:2.3V; Supply Voltage Max:6V; Reset Type:Active-High, Active-Low; Digital IC Case Style:TSOT-23; No. of Pins:8; Supply Current:29A; Delay Time:8.5ms ;RoHS Compliant: Yes
LTC2912ITS8-1#TR 制造商:Linear Technology 功能描述:Volt Supervisor Monitor 3.3V 8-Pin TSOT-23 T/R
LTC2912ITS8-1#TRMPBF 功能描述:IC VOLT MONITOR SNGL TSOT23-8 RoHS:是 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:100 系列:- 类型:简单复位/加电复位 监视电压数目:1 输出:开路漏极,开路漏极 复位:高有效/低有效 复位超时:最小为 250 ms 电压 - 阀值:4.37V,4.62V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:管件 产品目录页面:1337 (CN2011-ZH PDF)
LTC2912ITS8-1#TRPBF 功能描述:IC VOLT MONITOR SNGL TSOT23-8 RoHS:是 类别:集成电路 (IC) >> PMIC - 监控器 系列:- 标准包装:400 系列:- 类型:备用电池电路 监视电压数目:1 输出:开路漏极,推挽式 复位:高有效/低有效 复位超时:最小为 35 ms 电压 - 阀值:4.65V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-SOIC(0.295",7.50mm 宽) 供应商设备封装:16-SOIC W 包装:带卷 (TR) 其它名称:ADM691ARZ-REEL7TR
LTC2912ITS8-2#PBF 制造商:Linear Technology 功能描述:Volt Supervisor Monitor 3.3V 8-Pin TSOT-23 制造商:Linear Technology 功能描述:MONITOR 29uA 6V TSOT-23-8 制造商:Linear Technology 功能描述:MONITOR, 29uA, 6V, TSOT-23-8; No. of Supervisors / Monitors:1; Supply Voltage Min:2.3V; Supply Voltage Max:6V; Reset Type:Active-High, Active-Low; Digital IC Case Style:TSOT-23; No. of Pins:8; Supply Current:29A; Delay Time:8.5ms ;RoHS Compliant: Yes