参数资料
型号: LTC1436AIGN-PLL
厂商: Linear Technology
文件页数: 18/28页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM CM 24-SSOP
标准包装: 55
PWM 型: 电流模式
输出数: 1
频率 - 最大: 138kHz
占空比: 99%
电源电压: 3.5 V ~ 30 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 24-SSOP(0.154",3.90mm 宽)
包装: 管件
LTC1436A
LTC1436-PLL-A/LTC1437A
APPLICATIO N S I N FOR M ATIO N
The output of the phase detector is a complementary pair
of current sources charging or discharging the external
filter network on the PLL LPF pin. The relationship
between the PLL LPF pin and operating frequency is
shown in Figure 7. A simplified block diagram is shown in
Figure 8.
If the external frequency (f PLLIN ) is greater than the oscil-
lator frequency (f), current is sourced continuously, pull-
ing up the PLL LPF pin. When the external frequency is less
than f OSC , current is sunk continuously, 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 comparator 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 0.01 μ F to
0.1 μ F. Be sure to connect the low side of the filter to SGND.
The PLL LPF pin can be driven with external logic to obtain
a 1:1.9 frequency shift. The circuit shown in Figure 9 will
provide a frequency shift from f O to 1.9f O as the voltage
and V PLLLPF increases from 0V to 2.4V. Do not exceed 2.4V
on V PLLLPF .
1.3f O
3.3V OR 5V
f O
PLL LPF
2.4V MAX
18k
0.7f O
1436 F09
Figure 9. Directly Driving PLL LPF Pin
0
0.5
1.0
1.5
2.0
2.5
V PLLLPF (V)
EXTERNAL
1436 F07
Figure 7. Operating Frequency vs V PLLLPF
Low-Battery Comparator
The LTC1436A/LTC1437A have an on-chip low-battery
comparator which can be used to sense a low-battery
condition when implemented as shown in Figure 10. The
FREQUENCY
R LP
resistive divider R3, R4 sets the comparator trip point as
PHASE
2.4V
C LP
C OSC
follows:
V LBTRIP = 1 . 19 V ? 1 +
PLLIN
DETECTOR
PLL LPF
C OSC
?
?
R4 ?
R 3 ? ?
DIGITAL
PHASE/
FREQUENCY
OSC
V IN
50k
DETECTOR
R4
LBI
LTC1436A
LTC1437A
LBO
R3
+
1436 F08
SGND
1.19V REFERENCE
1436 F10
Figure 8. Phase-Locked Loop Block Diagram
Figure 10. Low-Battery Comparator
14367afb
18
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LTC1436AIGN-PLL#PBF 功能描述:IC REG CTRLR BUCK PWM CM 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1436AIGN-PLL#TR 功能描述:IC REG CTRLR BUCK PWM CM 24-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1436AIGN-PLL#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 24-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1436CGN 功能描述:IC REG CTRLR BUCK PWM CM 24-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1436CGN#PBF 制造商:Linear Technology 功能描述:Step-Down Switching Regulators