参数资料
型号: S-8521C25MC-BTKT2G
元件分类: 稳压器
英文描述: 0.05 A SWITCHING CONTROLLER, 72 kHz SWITCHING FREQ-MAX, PDSO5
封装: LEAD FREE, SOT-23, 5 PIN
文件页数: 16/44页
文件大小: 511K
代理商: S-8521C25MC-BTKT2G
STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_00
S-8520/8521 Series
Seiko Instruments Inc.
23
Application Circuits
1.
External adjustment of output voltage
In the S-8550/8521 Series, by adding external resistors (RA, RB) and a capacitor (CFB), the output voltage can be
adjusted or be set freely in the range of 1.5 to 6.0 V, as shown in Figure 14. Temperature gradient can be given by
inserting a thermistor in series to RA and RB.
S-8520/8521 Series
CC
RA
RB
D1
VOUT
VSS
+
VIN
OUT
EXT
+
R2
R1
Oscillation
Circuit
PWM control or PWM /
PFM switching control unit
Reference voltage
source with soft start
ON/OFF
______
Figure 14
Caution
The above connection diagram and constant will not guarantee successful operation. Perform
through evaluation using the actual application to set the constant.
The S-8520/8521 Series have an internal impedance of R1 and R2 between the VOUT pin and the VSS pin, as
shown in Figure 14.
Therefore, OUT (the output voltage) is determined by the output voltage value (VOUT) of the S-8520/8521 Series,
and the ratio of the parallel resistance value of external resistance (RB) and internal resistances (R1 + R2) of the IC,
to external resistance (RA). The output voltage is expressed by the following equation:
OUT = VOUT + VOUT × RA ÷ (RB //
*1(R
1 + R2))
*1.
// shows the combined resistance in parallel.
The voltage accuracy of the OUT set by resistances (RA and RB) is not only affected by the IC’s output voltage
accuracy (VOUT ±2.4 %), but also by the absolute precision of external resistances (RA and RB) in use and the
absolute value deviations of internal resistances (R1 and R2) in the IC.
Let us designate the maximum deviations of the absolute value of RA and RB by RA max. and RB max., respectively,
the minimum deviations by RA min. and RB min., respectively, and the maximum and minimum deviations of the
absolute value of R1 and R2 in the IC by (R1 + R2) max. and (R1 + R2) min., respectively. Then, the minimum
deviation value OUT min. and the maximum deviation value OUT max. of the OUT are expressed by the following
equations:
OUT min. = VOUT × 0.976 + VOUT × 0.976 × RA min. ÷ (RB max. // (R1 + R2) max.)
OUT max. = VOUT × 1.024 + VOUT × 1.024 × RA max. ÷ (RB min. // (R1 + R2) min.)
相关PDF资料
PDF描述
S-8520A31MC-AVQT2G 0.05 A SWITCHING CONTROLLER, 207 kHz SWITCHING FREQ-MAX, PDSO5
S-90N0113SMA-TFG 1000 mA, 30 V, N-CHANNEL, Si, SMALL SIGNAL, MOSFET
S-93C46AFJ-TB-SG 64 X 16 MICROWIRE BUS SERIAL EEPROM, PDSO8
S-I6498#21 15A, 125VAC, FEMALE, MAINS POWER CONNECTOR, SOLDER
S-I6519#01 15A, 125VAC, FEMALE, MAINS POWER CONNECTOR, SOLDER
相关代理商/技术参数
参数描述
S-8521C25MC-BXK-T2 制造商:SII 制造商全称:Seiko Instruments Inc 功能描述:PWM CONTROL & PWM/PFM CONTROL STEP-DOWN SWITCHING REGULATOR-CONTROLLERS
S-8521C27MC-BTM-T2 功能描述:DC/DC 开关控制器 2.7V Step-Dn PWM/PFM RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
S-8521C27MC-BTMT2G 功能描述:DC/DC 开关控制器 2.7V Step-Dn PWM/PFM RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
S-8521C27MC-BXM-T2 制造商:SII 制造商全称:Seiko Instruments Inc 功能描述:PWM CONTROL & PWM/PFM CONTROL STEP-DOWN SWITCHING REGULATOR-CONTROLLERS
S-8521C28MC-BTN-T2 功能描述:DC/DC 开关控制器 2.8V Step-Dn PWM/PFM RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK