LT1761ES5-1.8#TRMPBF Linear Technology, LT1761ES5-1.8#TRMPBF Datasheet - Page 15

• Manufacturer Part Number: LT1761ES5-1.8#TRMPBF
• Description: IC LDO REG 100MA 1.8V TSOT23-5
• Manufacturer: Linear Technology

Specifications of LT1761ES5-1.8#TRMPBF

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.8V
• Voltage - Input: Up to 20V
• Voltage - Dropout (typical): 0.3V @ 100mA
• Number Of Regulators: 1
• Current - Output: 100mA
• Current - Limit (min): 110mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-5, TSOT-5, TSOP-5
• Primary Input Voltage: 2.8V
• Output Voltage Fixed: 1.8V
• Dropout Voltage Vdo: 300mV
• No. Of Pins: 5
• Output Current: 100mA
• Voltage Regulator Case Style: SOT-23
• Operating Temperature Range: -40°C To
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LT1761ES5-1.8#TRMPBFTR

APPLICATIO S I FOR ATIO
Output Capacitance and Transient Response
The LT1761 regulators are designed to be stable with a
wide range of output capacitors. The ESR of the output
capacitor affects stability, most notably with small
capacitors. A minimum output capacitor of 1μF with an
ESR of 3Ω or less is recommended to prevent oscilla-
tions. The LT1761-X is a micropower device and output
transient response will be a function of output capaci-
tance. Larger values of output capacitance decrease the
peak deviations and provide improved transient response
for larger load current changes. Bypass capacitors, used
to decouple individual components powered by the
LT1761-X, will increase the effective output capacitor
value. With larger capacitors used to bypass the refer-
ence (for low noise operation), larger values of output
capacitors are needed. For 100pF of bypass capacitance,
2.2μF of output capacitor is recommended. With a 330pF
Figure 3. Ceramic Capacitor DC Bias Characteristics
–100
–20
–40
–60
–80
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
20
0
0
0
1
C
BYP
C
2
BYP
= 0
U
OUTPUT CAPACITANCE (μF)
= 100pF
Figure 2. Stability
4
C
DC BIAS VOLTAGE (V)
BYP
2
STABLE REGION
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
6
= 330pF
U
C
BYP
3
8
Y5V
> 3300pF
X5R
10
4
5 6 7 8 9
W
12
14
1761 F03
1761 F02
16
10
U
bypass capacitor or larger, a 3.3μF output capacitor is
recommended. The shaded region of Figure 2 defines the
region over which the LT1761 regulators are stable. The
minimum ESR needed is defined by the amount of bypass
capacitance used, while the maximum ESR is 3Ω.
Extra consideration must be given to the use of ceramic
capacitors. Ceramic capacitors are manufactured with a
variety of dielectrics, each with different behavior across
temperature and applied voltage. The most common
dielectrics used are specified with EIA temperature charac-
teristic codes of Z5U, Y5V, X5R and X7R. The Z5U and Y5V
dielectrics are good for providing high capacitances in a
small package, but they tend to have strong voltage and
temperature coefficients as shown in Figures 3 and 4.
When used with a 5V regulator, a 16V 10μF Y5V capacitor
can exhibit an effective value as low as 1μF to 2μF for the
DC bias voltage applied and over the operating tempera-
ture range. The X5R and X7R dielectrics result in more
stable characteristics and are more suitable for use as the
output capacitor. The X7R type has better stability across
temperature, while the X5R is less expensive and is avail-
able in higher values. Care still must be exercised when
using X5R and X7R capacitors; the X5R and X7R codes
only specify operating temperature range and maximum
capacitance change over temperature. Capacitance change
due to DC bias with X5R and X7R capacitors is better than
Y5V and Z5U capacitors, but can still be significant enough
to drop capacitor values below appropriate levels. Capaci-
tor DC bias characteristics tend to improve as component
case size increases, but expected capacitance at operating
voltage should be verified.
Figure 4. Ceramic Capacitor Temperature Characteristics
–100
–20
–40
–60
–80
40
20
0
–50
BOTH CAPACITORS ARE 16V,
1210 CASE SIZE, 10μF
–25
0
TEMPERATURE (°C)
25
50
Y5V
LT1761 Series
75
X5R
100
1761 F04
125
15
1761sfc