參數(shù)資料
型號(hào): LTC1875EGN
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: 15mA Quiescent Current 1.5A Monolithic Synchronous Step-Down Regulator
中文描述: 3 A SWITCHING REGULATOR, 605 kHz SWITCHING FREQ-MAX, PDSO16
封裝: 0.150 INCH, PLASTIC, SSOP-16
文件頁(yè)數(shù): 12/20頁(yè)
文件大小: 257K
代理商: LTC1875EGN
12
LTC1875
1875f
APPLICATIOU
W
U
U
filter network on the PLL_LPF pin. The relationship be-
tween the voltage on the PLL_LPF pin and operating
frequency is shown in Figure 5. A simplified block diagram
is shown in Figure 6.
If the external frequency (V
SYNC/MODE
) is greater than
550kHz, the center frequency, current is sourced continu-
ously, pulling up the PLL_LPF pin. When the external
frequency is less than 550kHz, current is sunk continu-
ously, pulling down the PLL_LPF pin. If the external and
internal frequencies are the same but exhibit a phase
difference, the current sources turn on for an amount of
time corresponding to the phase difference. Thus the
voltage on the PLL_LPF pin is adjusted until the phase and
frequency of the external and internal oscillators are
identical. At this stable operating point the phase com-
parator output is open and the filter capacitor C
LP
holds the
voltage.
The loop filter components C
LP
and R
LP
smooth out the
current pulses from the phase detector and provide a
stable input to the voltage controlled oscillator. The filter
components C
LP
and R
LP
determine how fast the loop
acquires lock. Typically R
LP
= 10k and C
LP
is 2200pF to
0.01
μ
F. When not synchronized to an external clock, the
internal connection to the VCO is disconnected. This
disallows setting the internal oscillation frequency by a DC
voltage on the V
PLLLPF
pin.
Figure 5. Relationship Between Oscillator Frequency
and Voltage at PLL_LPF Pin
DIGITAL
PHASE/
FREQUENCY
DETECTOR
SYNC/
MODE
PLL_LPF
2.4V
C
LP
1875 F06
R
LP
VCO
Figure 6. Phase-Locked Loop Block Diagram
Phase-Locked Loop and Frequency Synchronization
The LTC1875 has an internal voltage-controlled oscillator
and phase detector comprising a phase-locked loop. This
allows the MOSFET turn-on to be locked to the rising edge
of an external frequency source. The frequency range of
the voltage-controlled oscillator is 350kHz to 750kHz. The
phase detector used is an edge sensitive digital type that
provides zero degrees phase shift between the external
and internal oscillators. This type of phase detector will not
lock up on input frequencies close to the harmonics of the
VCO center frequency. The PLL hold-in range
f
H
is equal
to the capture range,
f
H
=
f
C
=
±
200kHz.
The output of the phase detector is a pair of complemen-
tary current sources charging or discharging the external
V
FB
LTC1875
0.8V
V
OUT
6V
SGND
R2
1875 F04
R1
Figure 4. Setting the LTC1875 Output Voltage
V
PLLLPF
(V)
0
O
1000
900
800
700
600
500
400
300
200
100
0
1875 F05
0.5
1
1.5
2
相關(guān)PDF資料
PDF描述
LTC1877 High Efficiency Monolithic Synchronous Step-Down Regulator(高效率,單片同步步降穩(wěn)壓器)
LTC1878 High Efficiency Monolithic Synchronous Step-Down Regulator(高效率,單片同步步降穩(wěn)壓器)
LTC1911-15 Low Noise, High Efficiency, Inductorless Step-Down DC/DC Converter
LTC1911EMS8-1.5 Low Noise, High Efficiency, Inductorless Step-Down DC/DC Converter
LTC1911EMS8-1.8 Low Noise, High Efficiency, Inductorless Step-Down DC/DC Converter
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC1875EGN#PBF 功能描述:IC REG BUCK SYNC ADJ 1.5A 16SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開(kāi)關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON(1.45x1) 產(chǎn)品目錄頁(yè)面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2
LTC1875EGN#TR 功能描述:IC REG BUCK SYNC ADJ 1.5A 16SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤(pán) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤(pán)
LTC1875EGN#TRPBF 功能描述:IC REG BUCK SYNC ADJ 1.5A 16SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤(pán) 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤(pán)
LTC1876EG 功能描述:IC REG CTRLR BST PWM CM 36-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤(pán) 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1876EG#PBF 功能描述:IC REG CTRLR BST PWM CM 36-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤(pán) 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX