參數(shù)資料
型號: LT3507AEFE#TRPBF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: SWITCHING REGULATOR, PDSO38
封裝: 4.40 MM, LEAD FREE, PLASTIC, TSSOP-38
文件頁數(shù): 10/28頁
文件大小: 372K
代理商: LT3507AEFE#TRPBF
LT3507A
18
3507af
APPLICATIONS INFORMATION
Figure 8. Two Different Modes of Output Voltage Tracking
Figure 9. Setup for Coincident and Ratiometric Tracking
Figure 10. Equivalent Input Circuit of Error Amplifier
outputs at start-up, they also disable the slaved channels
if the master channel falls out of regulation (due to a short
circuit or a collapsing input voltage).
Finally, be aware that the circuit in Figure 7e does not
work, because the power good comparators are disabled
in shutdown.
OUTPUT VOLTAGE TRACKING
The LT3507A allows the user to program how the output
ramps up by means of the TRK/SS pins. Through these
pins, any channel output can be set up to either coinci-
dently or ratiometrically track any other channel output.
This example will show the channel 2 output tracking the
channel 1 output, as shown in Figure 8. The TRK/SS2 pin
acts as a clamp on channel 2’s reference voltage. VOUT2
is referenced to the TRK/SS2 voltage when the TRK/SS2
< 0.8V and to the internal precision reference when TRK/
SS2 > 0.8V.
To implement the coincident tracking in Figure 8a, con-
nect an extra resistive divider to the output of channel 1
and connect its midpoint to the TRK/SS2 pin (Figure 9).
The ratio of this divider should be selected the same as
that of channel 2’s feedback divider (R5 = R3 and R6 =
R4). In this tracking mode, VOUT1 must be set higher than
VOUT2. To implement the ratiometric tracking in Figure 8b,
change the extra divider ratio to R5 = R1 and R6 = R2 +
ΔR. The extra resistance on R6 should be set so that the
TRK/SS2 voltage is ≥1V when VOUT1 is at its final value.
The need for this extra resistance is best understood with
the help of the equivalent input circuit shown in Figure 10.
Attheinputstageoftheerroramplifier,twocommonanode
diodes are used to clamp the equivalent reference voltage
and an additional diode is used to match the shifted com-
mon mode voltage. The top two current sources are of
the same amplitude. In the coincident mode, the TRK/SS2
R1
R2
=
VOUT1
0.8
– 1,
R3
R4
=
VOUT2
0.8
– 1
R5
R1
R6
R2
VOUT2
R4
R3
Tracking Setup
TO
VFB1
PIN
TO
TRK/SS2
PIN
TO
VFB2
PIN
VOUT1
COINCIDENT
R3
R4
R5 =
R6 =
RATIOMETRIC
R1
VOUT1/1V – 1
SELECTING VALUES FOR R5 AND R6
TIME
(8a) Coincident Tracking
VOUT1
VOUT2
OUTPUT
VOL
TAGE
TIME
3507A F08
(8b) Ratiometric Tracking
VOUT1
VOUT2
OUTPUT
VOL
TAGE
1.25A
+
I
D1
TRK/SS
0.8V
FB
D2
D3
3507A F10
EA2
相關(guān)PDF資料
PDF描述
LT3507AHUHF#TRPBF SWITCHING REGULATOR, PQCC38
LT3507AHFE#PBF SWITCHING REGULATOR, PDSO38
LT3507AEFE#PBF SWITCHING REGULATOR, PDSO38
LT3507AHUHF#PBF SWITCHING REGULATOR, PQCC38
LT3507AEUHF#TRPBF SWITCHING REGULATOR, PQCC38
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3507AEUHF#PBF 功能描述:IC REG QD BUCK/LINEAR 38QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507AEUHF#TRPBF 功能描述:IC REG QD BUCK/LINEAR 38QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507AHFE#PBF 功能描述:IC REG QD BUCK/LINEAR 38TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507AHFE#TRPBF 功能描述:IC REG QD BUCK/LINEAR 38TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507AHUHF#PBF 功能描述:IC REG QD BUCK/LINEAR 38QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*