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ZHCSNP8 November 2021 TPS7H1210-SEP

PRODUCTION DATA

8.1.1 Adjustable Operation

The TPS7H1210-SEP has an output voltage range of V_REF to –15.5 V. The nominal output voltage of the device is set by two external resistors, as shown in Figure 8-2.

R_{FB_TOP} and R_{FB_BOT} can be calculated for any output voltage range using Equation 2. To ensure stability under no-load conditions at |V_OUT| > |V_REF|, this resistive network must provide a current equal to or greater than 5 μA.

Equation 2.

R_{F B_T O P} = R_{F B_B O T} \times (\frac{V_{O U T}}{V_{R E F}} - 1), w h e r e \frac{(V_{R E F})}{R_{F B_B O T}} > 5 µ A

Table 8-1 shows the resistor combinations to achieve a few of the most common rails using commercially available, 1%-tolerance resistors. If greater voltage accuracy is required, consider the output voltage offset contributions because of the feedback pin current and use 0.1%-tolerance resistors.

Table 8-1 Example 1% Tolerance Resistors for Common Voltage Rails

V_OUT (V)	R_{FB_TOP} (kΩ)	R_{FB_BOT} (kΩ)	RESISTOR NETWORK BIAS CURRENT (µA)	RESISTOR ERROR CONTRIBUTION⁽¹⁾
–1.182	0	∞	N/A	N/A
–1.8	7.32	14	84.4	+0.001%
–2.5	11.3	10.2	115.9	+0.341%
–3.3	19.1	10.7	110.5	–0.245%
–5	34	10.5	112.6	–0.189%
–9	115	17.4	67.9	+0.066%
–10	445	15.4	76.8	–0.086%
–12	137	15	78.8	+0.187%
–15	133	11.3	104.6	–0.627%

(1) This is the error contribution due to the mismatch between the ideal resistor ratio and the actual resistor ratio (using the indicated resistor values). It does not include the error contribution due to the resistor tolerance itself. More accurate ratios are possible by using 0.1% tolerance resistors.